How to send POST request through RestTemplate with custom parameter in header

Question

I need to send post request with custom parameter("data" containing path) and set content type as text/plain. I looked through a ton of similar question but none of the solutions posted helped.

The method should list files from this directory.

my code is

    public List<FileWrapper> getFileList() {

    MultiValueMap<String, String> map = new LinkedMultiValueMap<String, String>();
    map.add("data", "/public/");

    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.TEXT_PLAIN);

    HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<MultiValueMap<String, String>>(
            map, headers);
    String url = "http://192.168.1.51:8080/pi/FilesServlet";
    restTemplate.getMessageConverters().add(new FormHttpMessageConverter());
    restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
    String response = restTemplate
            .postForObject(url, request, String.class);
    List<FileWrapper> list = new ArrayList<>();
    for (String part : response.split("\\|")) {
        System.out.println("part " + part);
        list.add(new FileWrapper(part));
    }
    return list;
}

Here's working code equivalent written in javascript:

function getFileList(direction){
$("div.file-list").html("<center><progress></progress></center>");
$.ajax({
  url: "http://192.168.1.51:8080/pi/FilesServlet",
  type: "POST",
  data: direction ,
  contentType: "text/plain"
})

The parameter is not added as the request returns empty string meaning the path is not valid. The expected response is file_name*file_size|file_name*file_size ...

Thanks in advance.

Answer 1

From the discussion in the comments, it's quite clear that your request object isn't correct. If you are passing a plain string containing folder name, then you don't need a MultiValueMap. Just try sending a string,

    String data = "/public/"
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.TEXT_PLAIN);

    HttpEntity<String> request = new HttpEntity<String>(
            data, headers);
    String url = "http://192.168.1.51:8080/pi/FilesServlet";
    restTemplate.getMessageConverters().add(new FormHttpMessageConverter());
    restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
    String response = restTemplate
            .postForObject(url, request, String.class);