This document provides an overview of Java servlets technology, including:
1. What Java servlets are and their main purposes and advantages such as portability, power, and integration with server APIs.
2. Key aspects of servlet architecture like the servlet lifecycle, the HttpServletRequest and HttpServletResponse objects, and how different HTTP methods map to servlet methods.
3. Examples of simple servlets that process parameters, maintain a session counter, and examples of deploying servlets in Eclipse IDE.
Network programming in java - PPT with Easy Programs and examples of Java InetAddress Class and java socket programming example.
Learn more @ http://java2all.com/technology/network-programming
This document provides an overview of client-server networking concepts in Java. It discusses elements like network basics, ports and sockets. It explains how to implement both TCP and UDP clients and servers in Java using socket classes. Sample code is provided for an echo client-server application using TCP and a quote client-server application using UDP. Exception handling for sockets is also demonstrated.
Threads allow multiple tasks to run concurrently within a single Java program. A thread represents a separate path of execution and threads can be used to improve performance. There are two main ways to create threads: by extending the Thread class or implementing the Runnable interface. Threads transition between different states like new, runnable, running, blocked, and terminated. Synchronization is needed to prevent race conditions when multiple threads access shared resources simultaneously. Deadlocks can occur when threads wait for each other in a circular manner.
The document discusses the Model-View-Controller (MVC) design pattern. MVC separates an application's logic into three main components: the model, the view, and the controller. The model manages the application's data and logic, the view displays the data to the user, and the controller interprets user input and updates the model. MVC improves separation of concerns and makes applications more modular, extensible, and testable. It is commonly used for web applications, where the server handles the model and controller logic while the client handles the view.
Servlets are Java programs that run on a web or application server and act as a middle layer between a request coming from a web browser or other HTTP client and databases or applications on the HTTP server. Servlets receive HTTP requests and return HTTP responses by accepting request parameters, generating dynamic content, accessing databases, and performing network communications using Java. Servlets are commonly used to add dynamic content to web pages and to access backend databases. The lifecycle of a servlet involves initialization, servicing client requests, and destruction. Common servlet APIs include classes for handling HTTP requests and responses, reading request parameters, using cookies and sessions.
This document discusses ADO.NET, which is a set of classes that allows .NET applications to communicate with databases. It provides advantages over classic ADO such as supporting both connected and disconnected data access. The key components of ADO.NET are data providers, which act as bridges between applications and databases, and the DataSet, which allows storing and manipulating relational data in memory disconnected from the database.
An introduction to REST and RESTful web services.
You can take the course below to learn about REST & RESTful web services.
https://www.udemy.com/building-php-restful-web-services/
This document provides an overview of Java Server Pages (JSP) technology. Some key points:
- JSP allows separation of work between web designers and developers by allowing HTML/CSS design and Java code to be placed in the same file.
- A JSP page is compiled into a servlet, so it can take advantage of servlet features like platform independence and database-driven applications.
- JSP pages use tags like <jsp:include> and <jsp:useBean> to include content and access JavaBeans. Scriptlets, expressions, declarations, and directives are also used.
- Implicit objects like request, response, out, and session are automatically available in JSP pages
Servlets are Java programs that run on the server-side and dynamically generate web pages using Java code. Servlets provide server-side programming functionality and are an effective replacement for CGI scripts. Servlets follow a standard API and can be deployed across distributed server environments.
This document provides an introduction and overview of ASP.NET and Web Forms. It discusses the background of ASP and how ASP.NET was developed to address challenges with ASP. The key features of ASP.NET, including Web Forms, Web Services, and the .NET Framework are described. The document then covers the ASP.NET programming model based on controls and events, and how postbacks maintain page state without requiring additional code. It also introduces the ASP.NET object model and server-side controls.
Socket programming in Java allows applications to communicate over the internet. Sockets are endpoints for communication that are identified by an IP address and port number. A socket connection is established between a client and server socket. The server creates a welcoming socket to accept client connection requests, then a separate connection socket to communicate with that client. Data can be sent bidirectionally over the connected sockets as input/output streams. UDP uses datagram sockets without a connection, requiring the explicit destination address on each message.
The servlet lifecycle consists of 5 steps: (1) loading and instantiation of servlets by the servlet container, (2) initialization via the init() method, (3) processing of client requests via the service() method, (4) finalization via the destroy() method, and (5) garbage collection. The service() method handles each client request by dispatching to doGet() or doPost() depending on the request type, while init() and destroy() are called once per servlet instance.
The document discusses exception handling in Java. It defines exceptions as runtime errors that occur during program execution. It describes different types of exceptions like checked exceptions and unchecked exceptions. It explains how to use try, catch, throw, throws and finally keywords to handle exceptions. The try block contains code that might throw exceptions. The catch block catches and handles specific exceptions. The finally block contains cleanup code that always executes regardless of exceptions. The document provides examples of exception handling code in Java.
This document provides an overview of Java applets, including:
- Applets are small Java programs that can be transported over the network and embedded in HTML pages.
- The main types of Java programs are standalone programs and web-based programs like applets.
- Applets differ from applications in that they have a predefined lifecycle and are embedded in web pages rather than running independently.
- The Applet class is the superclass for all applets and defines methods corresponding to the applet lifecycle stages like init(), start(), paint(), stop(), and destroy().
- Common methods for applets include drawString() for output, setBackground()/getBackground() for colors, and showStatus() to display in
JavaScript is a scripting language used primarily for client-side web development. It is based on the ECMAScript standard but browsers support additional objects like Window and DOM objects. JavaScript can be used to create dynamic and interactive effects on web pages like menus, alerts, and updating content without reloading. It is commonly used for form validation, AJAX applications, and other interactive features. The document provides examples of basic JavaScript concepts like variables, data types, operators, and control structures and how to embed scripts in HTML.
This document provides an overview of threads in Java, including:
- Threads allow for multitasking by executing multiple processes simultaneously. They are lightweight processes that exist within a process and share system resources.
- Threads can be created by extending the Thread class or implementing the Runnable interface. The run() method defines the code executed by the thread.
- Threads transition between states like new, runnable, running, blocked, and dead during their lifecycle. Methods like start(), sleep(), join(), etc. impact the thread states.
- Synchronization is used to control access to shared resources when multiple threads access methods and data outside their run() methods. This prevents issues like inconsistent data.
The document discusses Java event handling and the delegation event model. It describes key concepts like events, sources that generate events, and listeners that handle events. It provides examples of registering components as listeners and implementing listener interfaces. The delegation event model joins sources, listeners, and events by notifying listeners when sources generate events.
- The document provides an overview of servlet technology including servlet basics, lifecycle, important classes, and Apache Tomcat implementation.
- It describes how to set up a development environment with Tomcat and IDEs like Eclipse, and covers servlet structure, deployment, mapping, and configuration using the web.xml file.
- An example basic servlet class is shown extending HttpServlet and implementing doGet and doPost methods.
This document provides an overview of web application development and servlet technology. It discusses the history and evolution of web pages to dynamic web applications. It then defines web applications and the request-response model. Common Gateway Interface (CGI) is introduced as the first technique for dynamic content, along with its limitations which led to the creation of servlets. Key servlet concepts like the servlet interface, generic servlet, HTTP servlet, and servlet lifecycle methods are covered. The document also examines the HttpServletRequest and HttpServletResponse interfaces and their various methods. Finally, it discusses session tracking approaches including cookies and the session API.
The document provides an overview of key Java concepts including classes, objects, methods, constructors, inheritance, polymorphism, abstraction, and encapsulation. It defines classes like Circle and Shape that demonstrate these concepts. Circles have fields like radius and methods like area() and circumference(). The Shape class is abstract with abstract area() and circumference() methods that concrete subclasses like Circle must implement. Access modifiers like public, private, and protected are used to control access to class members.
Introduction to Java Programming Languagejaimefrozr
The document provides an introduction and history of the Java programming language. It discusses that Java was originally developed in 1991 by Sun Microsystems to be portable for consumer electronic devices. The document then summarizes the key capabilities of Java including being a general purpose language that can develop robust applications for desktops, servers, and mobile devices. It also outlines the Java language specifications, application programming interface containing predefined classes, and development tools available. Finally, it explains how Java's use of byte code and the Java Virtual Machine allows it to be highly portable across different operating systems.
This document provides an introduction and overview of the Java programming language. It discusses that Java was developed by Sun Microsystems in the 1990s as a general-purpose, object-oriented language designed for easy web and internet applications. The key principles of object-oriented programming like encapsulation, inheritance, and polymorphism are explained. Characteristics of Java like being simple, secure, portable, and having good performance are highlighted. A brief history of Java's development is also presented.
This extensive course covers all the topics which will definitely make you a Java Superstar. You can do almost anything in Java after this course. You will surely be a better programmer and better still a Elegant programmer after this course.
The document discusses several core Java concepts including:
1) Comments in Java code can be single-line or multiline javadoc comments.
2) Classes are fundamental in Java and describe data objects and methods that can be applied to objects.
3) Variables and methods have scopes determined by curly braces and a variable is only available within its scope.
This document provides an overview of the Java programming language including how it works, its features, syntax, and input/output capabilities. Java allows software to run on any device by compiling code to bytecode that runs on a virtual machine instead of a particular computer architecture. It is an object-oriented language with features like automatic memory management, cross-platform capabilities, and a robust class library.
This presentation provides an overview of the Java programming language. It discusses what Java is, where it is used, its features, how Java programs are translated and run on the Java Virtual Machine. It also covers Java concepts like object-oriented programming, data types in Java, garbage collection, and the development phases of a Java program. Finally, it proposes a project idea of developing an intranet mailing system and concludes by thanking the audience and asking if there are any questions.
This document provides an overview of Java fundamentals including its history, key components like the JDK and JRE, how bytecode and the JVM enable platform independence, and core object-oriented programming principles. It describes how Java was created in the early 1990s to control consumer devices, the development of applets for web browsers, and how bytecode compilation allows the same code to run on any device with a Java Virtual Machine.
This document provides an introduction to object oriented programming in Java. It outlines the course objectives which are to learn Java basics, object oriented principles, Java APIs, exception handling, files, threads, applets and swings. It discusses key characteristics of Java including being portable, object oriented and having automatic memory management. It also provides an overview of Java environments and tools, and includes an example "Hello World" Java program.
This document provides an overview of Java servlets including:
- What a Java servlet is and why they are used to generate dynamic web content
- The basic servlet architecture including the servlet lifecycle and how requests are handled
- Examples of simple servlets like one that displays a greeting based on a request parameter and an image counter servlet
- How servlets are deployed and configured using the Eclipse IDE
Servlets are Java classes that extend the functionality of a web server by dynamically generating web pages. Servlets use the Java programming language and are managed by a servlet container that handles loading, unloading, and directing requests. Servlets provide advantages over older technologies like CGI scripts such as better performance, portability, security, and access to full Java features. The basic servlet lifecycle involves initialization, handling requests, and destruction. Servlets can be generic or HTTP-specific, with HTTP servlets providing specialized methods for different HTTP request types. Sessions allow servlets to maintain state across multiple requests.
The document discusses Java servlets and Java Server Pages (JSP). It provides an introduction to HTTP and web interactions, and describes how servlets and JSPs allow Java code to generate dynamic web content. It explains the request-response cycle between clients and servers, and how servlets fit into this model. It also covers servlet containers, the servlet lifecycle, deployment descriptors, and developing and running servlets.
Http Server Programming in JAVA - Handling http requests and responsesbharathiv53
This ppt contains HTML forms and CGI; HTTP; Servlet Programming; The Life Cycle of a
Servlet; Using Tomcat for Servlet Development; A simple Servlet;
deployment of simple servlets, web server (Java web server / Tomcat/ Web
logic) The Servlet API; The Javax.servlet Package; Reading Servlet
Parameter; The Javax.servlet.http package; Handling HTTP Requests and
Responses, HTTP GET and POST methods, Using Cookies; Session
Tracking
The document discusses servlets, including their life cycle, handling HTTP requests and responses, and session tracking using cookies. It provides details on:
- The init(), service(), and destroy() methods that are central to a servlet's life cycle.
- How servlets can read data from HTTP requests using the HttpServletRequest interface and write data to HTTP responses using the HttpServletResponse interface.
- How servlets can maintain session state across requests using the HttpSession interface and cookies.
- Examples of simple servlets that retrieve and display request parameters, and handle GET and POST requests.
This document provides an overview of Java servlets, including what servlets are, their advantages over other technologies like CGI scripts, their lifecycle and program structure, deploying servlets on Tomcat, HTTP request methods, accessing request data, and redirecting URLs. Servlets are Java classes that extend functionality to handle HTTP requests and responses. They have advantages like faster performance than CGI scripts and reuse of the Java platform. The servlet lifecycle involves initialization, processing requests, and destruction. Servlets are deployed on a web container like Tomcat by compiling, configuring in web.xml, and placing in the webapps folder.
This document provides an overview of Java servlets including:
- Servlets allow Java code to generate dynamic web page content in response to HTTP requests. They are hosted by a servlet container inside a web server.
- The servlet lifecycle involves initialization, processing requests, and destruction. Common methods are init(), service(), destroy().
- The javax.servlet and javax.servlet.http APIs provide interfaces and classes for building servlets and handling HTTP requests/responses.
- Servlets can collaborate by forwarding or redirecting requests between servlets using methods like RequestDispatcher and HttpServletResponse.
- Session management techniques like cookies, hidden fields, and HTTP sessions allow servlets to maintain state across
Java Servlet Programming under Ubuntu Linux by Tushar B KuteTushar B Kute
The document provides information on programming simple servlets under Ubuntu GNU/Linux. It discusses what can be built with servlets, the benefits of servlets over CGI, definitions of servlet containers and servlet architecture. It also covers the servlet lifecycle, request and response objects, and the steps to write a simple servlet class, compile it, deploy it on Tomcat, and run it.
Servlet
Common Gateway Interface (CGI), Lifecycle of a Servlet, deploying a servlet, The Servlet API, Reading Servlet parameters, Reading Initialization parameters, Handling Http Request & Responses, Using Cookies and Sessions, connecting to a database using JDBC.
The document provides information on servlet fundamentals including definitions, applications, architecture, lifecycle, and development process. Some key points include:
- Servlets are Java programs that run on web servers and interact with clients via HTTP requests and responses. They provide dynamic content and process user input.
- Common servlet applications include search engines, e-commerce sites, and intranets.
- The servlet lifecycle includes initialization, processing requests, and destruction. Servlets remain loaded in memory between requests for improved performance over CGI.
- To develop a servlet, you create a class that implements the Servlet interface, define request handling methods, compile it, deploy it in a web container
1. The document discusses objectives and concepts related to building web applications using servlets, including HTTP methods, the request and response objects, the servlet lifecycle, initialization parameters, and redirecting versus forwarding requests.
2. It provides examples of servlet configuration in web.xml and describes how the container processes requests and maps them to servlets.
3. Key aspects of the request and response objects are outlined, such as accessing headers, cookies, and input/output streams.
This document provides information on servlets including:
- Servlets allow dynamic content and interaction for web applications and can be used to build search engines, e-commerce sites, and more.
- Servlets have better performance than CGI since they remain loaded in memory between requests rather than starting a new process for each request.
- Servlets follow a request-response lifecycle and provide APIs to handle HTTP requests and responses through the Servlet, HttpServletRequest, and HttpServletResponse interfaces.
The document discusses server-side programming and Java 2 Enterprise Edition (J2EE). It explains what J2EE is, its architecture and components. It describes the lifecycle of a servlet, including initialization, request handling, and destruction. It also discusses session management techniques in servlets like using cookies, URL rewriting, and hidden form fields to track user requests across multiple pages. Exception handling using request dispatchers is also covered.
Web Component Development Using Servlet & JSP Technologies (EE6) - Chapter 4...WebStackAcademy
Setting up a servlet environment
Servlets are Java programs that run on a Web server and build Web pages. Here are a few definitions:
Servlet Development Kits
Java Servlet Development Kit (JSDK) provides Servlet API classes (servlet.jar). Place servlet.jar into CLASSPATH, so that java classes can access it.
Servlet Engines
A servlet is a Java class that needs to be executed in a Java VM by servlet engine. The servlet engine loads the servlet class the first time the servlet is requested. The servlet then stays loaded to handle multiple requests until it is explicitly unloaded or the servlet engine is shut down.
Following are few WebServers that supports servlets:
Apache Tomcat
BEA WebLogic
IBM Websphere
Sun's Java Web Server (JWS)
Apache Tomcat.
Java Servlet Development Kit (JSDK)
The document provides information on various web server software, web application servers, HTTP requests and responses, and the differences between web servers and application servers. It also discusses servlets, web applications, and the servlet API. Specifically, it lists popular web server software like Apache HTTP Server, Microsoft IIS, and Apache Tomcat. It explains how web application servers extend web servers to support dynamic content through templates, programs, and databases. It also defines the key components of HTTP requests and responses.
This document provides an introduction to servlets, including concepts of CGI, advantages of servlets over CGI, servlet life cycle, servlet deployment, and servlet API. Some key points:
- CGI enables a web server to call an external program and pass HTTP request information, but has performance and scalability disadvantages due to starting a new process for each request.
- Servlets address CGI limitations by running within a JVM on the server, allowing requests to be handled on threads rather than processes for better performance.
- The servlet life cycle includes initialization via init(), processing requests via service()/doGet()/doPost(), and cleanup via destroy().
- Servlets are deployed by placing class
- Dynamic content generation is needed to satisfy user needs that cannot be met with static content alone, such as data from databases or responses to queries. This requires server-side architectures that dynamically generate content.
- HTTP is a stateless protocol in which each client request is associated with a method like GET or POST specifying the desired action. GET retrieves information while POST submits information of unlimited length in the request body.
- A Java servlet is a pluggable program that extends server functionality. Servlets run inside a servlet container on the server and are portable across systems.
The document provides an overview of the RichFaces framework including:
- What RichFaces is and its history
- Installing and configuring RichFaces
- Ajax action components like a4j:support, a4j:commandButton, a4j:poll
- UI components like menus, calendar, trees
- Examples of using various RichFaces components
This document discusses JSP custom tags, including:
- Tag files allow defining custom tags and should be used to modularize JSP output or reuse behavior.
- There are two types of tag files: stand-alone tags and tags containing other tags/text. Both can have attributes.
- The document demonstrates creating a simple "hello" tag and using attributes, JSTL, modifying body content, and exporting variables from tags.
- Custom tags can help build reusable components, iterate/filter content, and encapsulate logic in JSPs.
JSF (JavaServer Faces) provides an event model, validation model, and conversion model to handle user input and events in web applications. The event model defines different event types like action, value change, and phase events that allow components to notify listeners of user interactions. The validation model validates user input on UI components using standard and custom validators. The conversion model converts between view data types like strings and model data types using standard and custom converters.
This document provides an overview of JavaServer Faces (JSF), including:
- An introduction to JSF and what it is
- A description of the JSF request lifecycle and faces servlet
- An explanation of JSF component models and commonly used tags
- A step-by-step guide for creating a basic "Hello World" JSF application
- Details about JSP architectures (Model 1 and Model 2) that provide context for JSF
The Unified Expression Language (EL) provides a simplified way to access objects in JSP and JSF, allowing values to be retrieved from or assigned to JavaBeans properties and elements in collections, and supporting implicit objects, operators, and conditional evaluation. EL was created to unify the different expression languages used in JSP and JSF and addresses issues with earlier technologies like JSTL and JSP by providing a more powerful yet concise syntax. EL evaluates expressions and returns values or references to support both immediate and deferred access of data in web applications.
- JavaServer Pages (JSP) is a technology for generating dynamic web content that allows Java code to be embedded within HTML pages. The Java code is executed on the server to produce HTML that is then sent to the client.
- JSP pages make it easy to create dynamic web applications using simple scripting elements like expressions, scriptlets, and directives that are translated into Java servlets. They provide many predefined variables like request, response, and session to access data.
- JSP pages are compiled into Java servlet classes that operate in a request/response lifecycle like servlets. The servlet classes are stored and executed by the web container to handle requests and generate the HTML responses.
The document provides an overview of Java web applications and deployment using Apache Tomcat web application server. It discusses what a web container is, how Tomcat works as a web container, and how to install, run and configure Tomcat. It also describes how to create Java web applications that can be deployed as WAR files, and how to define servlets and mappings in the web deployment descriptor (web.xml). Finally, it shows how to create a simple web application and deploy it on Tomcat.
This document provides an introduction to Cascading Style Sheets (CSS). It explains that CSS is used to separate a document's content from its presentation or style. CSS defines elements like fonts, colors, spacing and layout. Styles can be applied inline, embedded in <style> tags, or linked via an external CSS file. The document outlines CSS syntax, selectors, and precedence of different styling methods. CSS provides control over text formatting, colors, spacing, and positioning of HTML elements.
The document discusses HTML tables and forms. It covers core table tags like <table>, <tr>, and <td> and how to structure tables with headers, bodies, and footers. It also explains how to customize tables using attributes like cellspacing, cellpadding, colspan, and rowspan. For forms, it describes common form controls like text fields, textareas, radio buttons, checkboxes and how to lay them out in a form with a submit button. It provides an example form to demonstrate these concepts.
The document provides an introduction to HTML basics including text, images, tables and forms. It covers the structure of an HTML document with the <head> and <body> sections. It describes common tags for headings, paragraphs, hyperlinks and images. It also discusses attributes, comments, and different ways to style and format text in HTML. The document is intended to teach HTML fundamentals.
The document provides an overview of key web technologies including:
- The World Wide Web (WWW) is a global system of interconnected documents accessed via URLs over HTTP. It consists of web servers that host content and web browsers that render pages.
- HTTP is the fundamental protocol of the WWW. It uses a request-response model where clients make requests that servers respond to. Common requests are GET to retrieve resources and POST to submit data.
- Cookies are small pieces of data stored by the client that are included in future HTTP requests to maintain state across interactions.
The document provides an overview of Dynamic HTML (DHTML) and its core technologies: HTML, CSS, JavaScript, and the DOM. It explains that DHTML allows dynamic and interactive web pages by combining these technologies. JavaScript is described as the scripting language that defines dynamic behavior, handling events and user interactions to manipulate the DOM. The document gives examples of common JavaScript functions, syntax elements, and how to incorporate JavaScript code into web pages.
The document provides steps for converting an image-based website design into XHTML and CSS code. It discusses identifying sections, deciding on a layout type, distinguishing content from style, and creating the basic page structure with appropriate HTML tags. Floating DIVs and DIVs that behave like tables are described as options for multi-column page layouts. Centering content, vertical alignment, and image formats are also covered.
The document discusses different XML parsers in Java including DOM, SAX, and StAX. DOM represents the XML document as an in-memory tree which allows flexible processing but uses more memory. SAX is event-driven and reads the XML sequentially using less memory. StAX is similar to SAX but simplified and "pull"-based where the developer manually navigates elements. The document also covers using JAXP for XML processing independence and the key classes involved in DOM and StAX parsing.
This document provides an introduction to XML, including:
1) It describes XML as a universal language for describing structured data in a platform-independent way, supported by the W3C.
2) It explains some key differences between XML and HTML, and when each should be used.
3) It discusses XML schemas like DTD and XSD that define rules for XML documents and enable validation.
This document provides an overview of using JDBC (Java Database Connectivity) to access databases from Java applications. It covers the main JDBC concepts like drivers, connections, statements, result sets, and transactions. It also describes the typical steps for querying and updating databases using JDBC: establishing a connection, creating statements, executing SQL statements, processing result sets, and closing resources. The document includes examples for connecting to Oracle and ODBC databases and using prepared statements. It discusses best practices like using connection pools, tuning transactions, and optimizing SQL queries.
The document provides an overview of common data structures including lists, stacks, queues, trees, and hash tables. It describes each data structure, how it can be implemented both statically and dynamically, and how to use the core Java classes like ArrayList, Stack, LinkedList, and HashMap that implement these structures. Key points covered include common operations for each structure, examples of using the Java classes, and applications like finding prime numbers in a range or matching brackets in an expression.
The DealBook is our annual overview of the Ukrainian tech investment industry. This edition comprehensively covers the full year 2023 and the first deals of 2024.
Transcript: Details of description part II: Describing images in practice - T...BookNet Canada
This presentation explores the practical application of image description techniques. Familiar guidelines will be demonstrated in practice, and descriptions will be developed “live”! If you have learned a lot about the theory of image description techniques but want to feel more confident putting them into practice, this is the presentation for you. There will be useful, actionable information for everyone, whether you are working with authors, colleagues, alone, or leveraging AI as a collaborator.
Link to presentation recording and slides: https://bnctechforum.ca/sessions/details-of-description-part-ii-describing-images-in-practice/
Presented by BookNet Canada on June 25, 2024, with support from the Department of Canadian Heritage.
論文紹介:A Systematic Survey of Prompt Engineering on Vision-Language Foundation ...Toru Tamaki
Jindong Gu, Zhen Han, Shuo Chen, Ahmad Beirami, Bailan He, Gengyuan Zhang, Ruotong Liao, Yao Qin, Volker Tresp, Philip Torr "A Systematic Survey of Prompt Engineering on Vision-Language Foundation Models" arXiv2023
https://arxiv.org/abs/2307.12980
Scaling Connections in PostgreSQL Postgres Bangalore(PGBLR) Meetup-2 - MydbopsMydbops
This presentation, delivered at the Postgres Bangalore (PGBLR) Meetup-2 on June 29th, 2024, dives deep into connection pooling for PostgreSQL databases. Aakash M, a PostgreSQL Tech Lead at Mydbops, explores the challenges of managing numerous connections and explains how connection pooling optimizes performance and resource utilization.
Key Takeaways:
* Understand why connection pooling is essential for high-traffic applications
* Explore various connection poolers available for PostgreSQL, including pgbouncer
* Learn the configuration options and functionalities of pgbouncer
* Discover best practices for monitoring and troubleshooting connection pooling setups
* Gain insights into real-world use cases and considerations for production environments
This presentation is ideal for:
* Database administrators (DBAs)
* Developers working with PostgreSQL
* DevOps engineers
* Anyone interested in optimizing PostgreSQL performance
Contact info@mydbops.com for PostgreSQL Managed, Consulting and Remote DBA Services
How Social Media Hackers Help You to See Your Wife's Message.pdfHackersList
In the modern digital era, social media platforms have become integral to our daily lives. These platforms, including Facebook, Instagram, WhatsApp, and Snapchat, offer countless ways to connect, share, and communicate.
How RPA Help in the Transportation and Logistics Industry.pptxSynapseIndia
Revolutionize your transportation processes with our cutting-edge RPA software. Automate repetitive tasks, reduce costs, and enhance efficiency in the logistics sector with our advanced solutions.
Paradigm Shifts in User Modeling: A Journey from Historical Foundations to Em...Erasmo Purificato
Slide of the tutorial entitled "Paradigm Shifts in User Modeling: A Journey from Historical Foundations to Emerging Trends" held at UMAP'24: 32nd ACM Conference on User Modeling, Adaptation and Personalization (July 1, 2024 | Cagliari, Italy)
Support en anglais diffusé lors de l'événement 100% IA organisé dans les locaux parisiens d'Iguane Solutions, le mardi 2 juillet 2024 :
- Présentation de notre plateforme IA plug and play : ses fonctionnalités avancées, telles que son interface utilisateur intuitive, son copilot puissant et des outils de monitoring performants.
- REX client : Cyril Janssens, CTO d’ easybourse, partage son expérience d’utilisation de notre plateforme IA plug & play.
Comparison Table of DiskWarrior Alternatives.pdfAndrey Yasko
To help you choose the best DiskWarrior alternative, we've compiled a comparison table summarizing the features, pros, cons, and pricing of six alternatives.
Quantum Communications Q&A with Gemini LLM. These are based on Shannon's Noisy channel Theorem and offers how the classical theory applies to the quantum world.
The Rise of Supernetwork Data Intensive ComputingLarry Smarr
Invited Remote Lecture to SC21
The International Conference for High Performance Computing, Networking, Storage, and Analysis
St. Louis, Missouri
November 18, 2021
Fluttercon 2024: Showing that you care about security - OpenSSF Scorecards fo...Chris Swan
Have you noticed the OpenSSF Scorecard badges on the official Dart and Flutter repos? It's Google's way of showing that they care about security. Practices such as pinning dependencies, branch protection, required reviews, continuous integration tests etc. are measured to provide a score and accompanying badge.
You can do the same for your projects, and this presentation will show you how, with an emphasis on the unique challenges that come up when working with Dart and Flutter.
The session will provide a walkthrough of the steps involved in securing a first repository, and then what it takes to repeat that process across an organization with multiple repos. It will also look at the ongoing maintenance involved once scorecards have been implemented, and how aspects of that maintenance can be better automated to minimize toil.
Are you interested in dipping your toes in the cloud native observability waters, but as an engineer you are not sure where to get started with tracing problems through your microservices and application landscapes on Kubernetes? Then this is the session for you, where we take you on your first steps in an active open-source project that offers a buffet of languages, challenges, and opportunities for getting started with telemetry data.
The project is called openTelemetry, but before diving into the specifics, we’ll start with de-mystifying key concepts and terms such as observability, telemetry, instrumentation, cardinality, percentile to lay a foundation. After understanding the nuts and bolts of observability and distributed traces, we’ll explore the openTelemetry community; its Special Interest Groups (SIGs), repositories, and how to become not only an end-user, but possibly a contributor.We will wrap up with an overview of the components in this project, such as the Collector, the OpenTelemetry protocol (OTLP), its APIs, and its SDKs.
Attendees will leave with an understanding of key observability concepts, become grounded in distributed tracing terminology, be aware of the components of openTelemetry, and know how to take their first steps to an open-source contribution!
Key Takeaways: Open source, vendor neutral instrumentation is an exciting new reality as the industry standardizes on openTelemetry for observability. OpenTelemetry is on a mission to enable effective observability by making high-quality, portable telemetry ubiquitous. The world of observability and monitoring today has a steep learning curve and in order to achieve ubiquity, the project would benefit from growing our contributor community.
Coordinate Systems in FME 101 - Webinar SlidesSafe Software
If you’ve ever had to analyze a map or GPS data, chances are you’ve encountered and even worked with coordinate systems. As historical data continually updates through GPS, understanding coordinate systems is increasingly crucial. However, not everyone knows why they exist or how to effectively use them for data-driven insights.
During this webinar, you’ll learn exactly what coordinate systems are and how you can use FME to maintain and transform your data’s coordinate systems in an easy-to-digest way, accurately representing the geographical space that it exists within. During this webinar, you will have the chance to:
- Enhance Your Understanding: Gain a clear overview of what coordinate systems are and their value
- Learn Practical Applications: Why we need datams and projections, plus units between coordinate systems
- Maximize with FME: Understand how FME handles coordinate systems, including a brief summary of the 3 main reprojectors
- Custom Coordinate Systems: Learn how to work with FME and coordinate systems beyond what is natively supported
- Look Ahead: Gain insights into where FME is headed with coordinate systems in the future
Don’t miss the opportunity to improve the value you receive from your coordinate system data, ultimately allowing you to streamline your data analysis and maximize your time. See you there!
2. Contents Java Servlets Technology Overview What is a Java Servlet? Servlet Services Why Use Servlets? Time Servlet – Example Deploying Servlets on Eclipse IDE Servlets Architecture Servlets API Servlets Life-Cycle
3. Contents (2) Servlet Examples Processing Parameters – Hello Servlet Image Counter Servlet Using Sessions What is a Session? The Sessions API Session Timeout Session Examples Login / Logout Application The Browser's Cache Problems
5. What is a Java Servlet? Java Servlets are: Technology for generating dynamic Web pages (like PHP, ASP, ASP.NET, ...) P rotocol and platform-independent server side components, written in Java , which extend the standard Web servers Java programs that serve HTTP requests The HttpServlet class Provides d ynamic Web content generation (HTML, XML, …)
6. What is a Java Servlet? (2) Servlets P rovide a general framework for services built on the request-response paradigm Portable to any Java application server Have access to the entire family of Java and Java EE APIs JDBC, Persistence, EJB, JMS, JAX-WS, JTA, JTS, RMI, JNDI, JAXP, ... Fundamental part of all Java Web application technologies (JSP, JSF, ...)
7. Servlet Services Java Servlets provide many useful services Provides low-level API for building Internet services Serves as foundation to JavaServer Pages (JSP) and JavaServer Faces (JSF) technologies Can deliver multiple types of data to any client XML, HTML, WML, GIF, etc... Can serve as “Controller” of JSP/Servlet application
8. Why Use Servlets? Portability Write once, serve everywhere Power Can take advantage of all Java APIs Elegance Simplicity due to abstraction Efficiency & Endurance Highly scalable
9. Why Use Servlets? (2) Safety Strong type-checking Memory management Integration Servlets tightly coupled with server Extensibility & Flexibility Servlets designed to be easily extensible, though currently optimized for HTTP uses Flexible invocation of servlet (SSI, servlet-chaining, filters, etc.)
10. Time Servlet – Example import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class Time Servlet extends HttpServlet { public void doGet(HttpServletRequest aRequest, HttpServletResponse aResponse) throws ServletException, IOException { PrintWriter out = aResponse.getWriter(); out.println("<HTML>"); out.println("The time is: " + new java.util.Date()); out.println("</HTML>"); } }
16. Servlets Architecture The HttpServlet class Serves client's HTTP requests For each of the HTTP methods, GET, POST, and others , there is c orresponding method : doGet ( … ) – serves HTTP GET requests doPost ( … ) – serves HTTP POST requests doPut ( … ) , doHead ( … ) , doDelete ( … ) , doTrace ( … ) , doOptions ( … ) The Servlet usually must implement one of the first two methods or the service( … ) method
17. Servlets Architecture (2) The HttpServletRequest object Contains the request data from the client HTTP request headers Form data and query parameters Other client data (cookies, path, etc.) The HttpServletResponse object Encapsulates data sent back to client HTTP response headers (content type, cookies, etc.) Response body (as OutputStream )
18. Servlets Architecture (3) The HTTP GET method is used when: The processing of the request does not change the state of the server The amount of form data is small You want to allow the request to be bookmarked The HTTP POST method is used when: The processing of the request changes the state of the server, e.g. storing data in a DB The amount of form data is large The contents of the data should not be visible in the URL (for example, passwords)
19. Servlets API The most important servlet functionality: Retrieve the HTML form parameters from the request (both GET and POST parameters) Retrieve a servlet initialization parameter Retrieve HTTP request header information HttpServletRequest.getParameter( String ) ServletConfig.getInitParameter () HttpServletRequest.getHeader( String )
20. Servlets API (2) Set an HTTP response header / content type Acquire a text stream for the response Acquire a binary stream for the response Redirect an HTTP request to another URL HttpServletResponse.setHeader (<name>, <value>) / HttpServletResponse.setContentType( String ) HttpServletResponse.getWriter() HttpServletResponse . getOutputStream() HttpServletResponse.sendRedirect()
21. Servlets Life-Cycle You can provide an implementation of these methods in HttpServlet descendent classes to manipulate the servlet instance and the resources it depends on The Web container manages the life cycle of servlet instances The life-cycle methods should not be called by your code init() ...() service() doGet() doPost() doDelete() destroy() doPut() New Destroyed Running
22. The init() Method Called by the Web container when the servlet instance is first created The Servlets specification guarantees that no requests will be processed by this servlet until the init method has completed Override the init() method when: You need to create or open any servlet-specific resources that you need for processing user requests You need to initialize the state of the servlet
23. The service() Method Called by the Web container to process a user request Dispatches the HTTP requests to doGet( … ) , doPost( … ) , etc. depending on the HTTP request method (GET, POST, and so on) Sends the result as HTTP response Usually we do not need to override this method
24. The destroy() Method Called by the Web container when the servlet instance is being eliminated The Servlet specification guarantees that all requests will be completely processed before this method is called Override the destroy method when: You need to release any servlet-specific resources that you had opened in the init() method You need to persist the state of the servlet
26. Processing Parameters – Hello Servlet We want to create a servlet that takes an user name as a parameter and says "Hello, <user_name>" We need HTML form with a text field The servlet can later retrieve the value entered in the form field <form method=" GET or POST " action=" the servlet "> <input type="text" name=" user_name "> </form> String n ame = r equest.getParameter("user_name");
27. Hello Servlet – Example <html><body> <form method="GET" action="HelloServlet"> Please enter your name: <input type="text" name=" user_name "> <input type="submit" value="OK"> </form> </body></html> HelloForm.html import java.io.*; import javax.servlet.*; import javax.servlet.http.*; public class HelloServlet extends HttpServlet { Hello Servlet . java
28. Hello Servlet – Example public void doGet(HttpServletRequest r equest, HttpServletResponse r esponse) throws ServletException, IOException { r esponse.setContentType("text/html"); ServletOutputStream out = r esponse.getOutputStream(); String userName = r equest.getParameter("user_name"); out.println("<html> <head> "); out.println("<title>Hello Servlet</title>"); out.println("</head><body>"); out.println("<h1>Hello, " + userName + "</h1>"); out.println("</body></html>"); } Hello Servlet . java
32. Hello Servlet – HTTP Request What happens when the user enters his name? Internet Explorer (IE) sends the following HTTP request to Tomcat GET /FirstWebApp/HelloServlet?user_name=Nakov HTTP/1.1 Accept: image/gif, image/x-xbitmap, image/jpeg,image/pjpeg, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-shockwave-flash, */* Accept-Language: bg Accept-Encoding: gzip, deflate User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; Q312461) Host: nakov:808 4 Connection: Keep-Alive
33. Hello Servlet – HTTP Response What happens when Tomcat receive and process the HTTP request Tomcat sends the following HTTP response to Internet Explorer HTTP/1.1 200 OK Content-Length: 100 Date: Fri, 26 Mar 200 6 10:06:28 GMT Server: Apache-Coyote/1.1 <html><head> <title>Hello Servlet</title> </head><body> <h1>Hello, Nakov</h1> </body></html>
34. Image Counter Servlet We want to create a servlet that displays an image counter (as JPEG image) The servlet should maintain an internal counter Can be initialized in the init() method and incremented in the doGet () method It should produce binary output (the JPEG) image The content type should be set to "image/jpeg"
35. Image Counter Servlet (2) import javax.servlet.*; import javax.servlet.http.*; ... public class ImageCounterServlet extends HttpServlet { private String mStartDate; private int mVisitCounter; public void init() { mStartDate = (new Date()).toString(); mVisitCounter = 0; } public BufferedImage createImage(String msg) { ... }
36. Image Counter Servlet (3) public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String msg; synchronized(this) { mVisitCounter++; msg = "" + mVisitCounter + " visits since " + mStartDate; } BufferedImage image = createImage(msg); response.setContentType("image/jpeg"); OutputStream out = response.getOutputStream(); // Encode the image in JPEG format and // write the image to the output stream } }
39. What is a Session? A session is a state associated with particular user that is maintained at the server side Sessions persist between the HTTP requests Sessions e nable creating applications that depend on individual user data. For example: Login / logout functionality Wizard pages Shopping c arts Personalization s ervices Maintaining state about the user’s preferences
40. Sessions in Servlets Servlets include a built-in Session s API Sessions are maintained automatically, with no additional coding The Web container associates an unique HttpSession object to each different client Different clients have different session objects at the server Requests from the same client have the same session object Sessions can store various data
41. The Sessions API The sessions API allows To get the HttpSession object from the HTTPServletRequest object Extract data from the user’s session object Append data to the user’s session object Extract meta-information about the session object, e.g. when was the session created
42. Getting The Session Object To get the session object use the method HttpServletRequest.getSession() Example: If the user already has a session, the existing session is returned If no session still exists, a new one is created and returned If you want to know if this is a new session, call the isNew() method HttpSession session = request.getSession();
43. Behind T he Scenes When you call getSession () each user is automatically assigned a unique Session ID How does this Session ID get to the user? Option 1: If the browser supports cookies, the servlet will automatically create a session cookie, and store the session ID within the cookie In Tomcat, the cookie is called JSESSIONID Option 2: If the browser does not support cookies, the servlet will try to extract the session ID from the URL
44. Extracting Data From The Session The s ession object works like a HashMap E nables storing any type of Java object Objects are stored by key (like in hash tables) Extracting existing object: Getting a list of all “keys” associated with the session Integer accessCount = (Integer) session.getAttribute("accessCount"); Enumeration attributes = request.getAttributeNames();
45. Storing Data In The Session We can store data in the session object for using it later Objects in the session can be removed when not needed more HttpSession session = request.getSession(); session.setAttribute("name", "Svetlin Nakov"); session. remove Attribute("name");
46. Getting Additional Session Information Getting the unique session ID associated with this user, e.g. gj9xswvw9p Checking if the session was just created Checking when the session was first created Checking when the session was last active public boolean isNew(); public String getId(); public long getLastAccessedTime(); public long getCreationTime();
47. Session Timeout We can get the maximal session validity interval ( in seconds ) After such interval of inactivity the session is automatically invalidated We can modify the maximal inactivity interval A negative value specifies that the session should never time out public int getMaxInactiveInterval(); public void setMaxInactiveInterval (int seconds) ;
48. Terminating Sessions To terminate session manually use the method: Typically done during the "user logout" The session can become invalid not only manually Sessions can expire automatically due to inactivity public void invalidate() ;
49. Login / Logout – Example We want to create a simple Web application that restricts the access by login form We will use sessions to store information about the authenticated users We will use the key "username" When it present, there is a logged in user During the login we will add the user name in the session Logout will invalidate the session The main servlet will check the current user
55. The Browser's Cache Problems Most Web browsers use caching of the displayed pages and images This can cause the user to see old state of the pages Seems like a bug in the application To prevent showing the old state we need to disable the browser cache: response.setHeader("Pragma", "No-cache"); response.setDateHeader("Expires", 0); response.setHeader("Cache-Control", "no-cache");
56. Problems Create a servlet that prints in a table the numbers from 1 to 1000 and their square root. Create a servlet that takes as parameters two integer numbers and calculates their sum. Create a HTML form that invokes the servlet. Try to use GET and POST methods. Implement a servlet that plays the "Number guess game". When the client first invoke the servlet it generates a random number in the range [1..100]. The user is asked to guess this number. At each guess the servlet says only "greater" or "smaller". The game ends when the user tell the number.
57. Homework Create a servlet that takes as a parameter a number and displays it as image that is hard to be recognized by OCR software. The image should have intentionally inserted defects. Create an HTML form and a servlet for performing conversions of distances from one metric to another. The metrics that should be supported are: meter, centimeter, kilometer, foot, inch, yard, mile. 1 cm = 0.01 meters 1 km = 1000 meters 1 foot = 0.3048 meters 1 inch = 0.0254 meters 1 yard = 0.9144 meters 1 mile = 1609.344 meters
58. Homework (2) Create a sequence of HTML forms and servlets that allow entering information about a student. The information is entered in 3 steps in 3 separate forms: Step 1: First name, last name, age Step 2: Address (country, town, street) Step 3: University, faculty, specialty The data entered in the 3 steps should be stored in the session and finally displayed. Create a servlet that reads an image (from WEB-INFmgogo.gif ) and returns it.
Editor's Notes
## * * 07/16/96
## * * 07/16/96
## * * 07/16/96 Example of HTTP GET: Google search Example of HTTP POST: Login page
## * * 07/16/96
## * * 07/16/96
## * * 07/16/96
## * * 07/16/96
Note: As of Servlet 2.2, the getValue() method is now deprecated. Use getAttribute() instead.
Note: As of Servlet 2.2, the getValue() method is now deprecated. Use getAttribute() instead.