Set up two template resolvers for JSP and Thymeleaf

Question

I have an existing Spring Boot application which uses JSP for views. I would like to move the view technology over to Thymeleaf, progressively.

The JSP view resolver is set up in application.properties:

spring.mvc.view.prefix=/WEB-INF/views/
spring.mvc.view.suffix=.jsp

The JSPs are located in:

src/main/resources/META-INF/resources/WEB-INF/views/

Is it possible to add a second view-resolver for Thymeleaf, for views which do not exist as JSP? So that the application tries both view-resolvers when a view is requested.

Edit

I have also tried with the following configuration, without success:

@Bean
public InternalResourceViewResolver jspViewResolver() {
    final InternalResourceViewResolver vr = new InternalResourceViewResolver();
    vr.setPrefix("/META-INF/resources/WEB-INF/views/");
    vr.setSuffix(".jsp");
    vr.setViewClass(JstlView.class);
    vr.setOrder(1);
    return vr;
}

@Bean
public TemplateResolver templateResolver() {
    final ServletContextTemplateResolver tr = new ServletContextTemplateResolver();
    tr.setPrefix("templates/th/");
    tr.setSuffix(".html");
    tr.setTemplateMode("HTML5");
    return tr;
}

@Bean
public SpringTemplateEngine templateEngine() {
    final SpringTemplateEngine te = new SpringTemplateEngine();
    // te.addTemplateResolver(jspViewResolver());
    te.setTemplateResolver(templateResolver());
    te.setMessageSource(databaseMessageSource);
    return te;
}

@Bean
public ViewResolver viewResolver() {
    final ThymeleafViewResolver vr = new ThymeleafViewResolver();
    vr.setTemplateEngine(templateEngine());
    vr.setOrder(2);
    return vr;
}

Answer 1

You might try out to configure it through Java Config.

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.servlet.config.annotation.ViewResolverRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
import org.thymeleaf.spring4.view.ThymeleafViewResolver;

@SpringBootApplication
public class Application extends WebMvcConfigurerAdapter{

    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        registry.viewResolver(new ThymeleafViewResolver());

        InternalResourceViewResolver internalResourceViewResolver = new InternalResourceViewResolver();
        internalResourceViewResolver.setViewClass(JstlView.class);
        internalResourceViewResolver.setPrefix("/WEB-INF/views");
        internalResourceViewResolver.setSuffix(".jsp");
        registry.viewResolver(internalResourceViewResolver);
    }

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Keep in mind that InternalResourceViewResolver should come last.

Also another useful answers on SO

1. How to use multiple ViewResolvers in Spring?
2. Spring MVC with multiple view resolvers