[ Calling a Rest URL written in Spring ]

I have a service like

@RequestMapping("/data")
@ResponseBody
public String property(@ModelAttribute("userDto") UserDto userDto ) {
    System.out.println(userDto.getUsername());
    System.out.println(userDto.getPassword());
    return "Hello";
}

How do I call this WebService from a client. I wrote

    UserDto userDto = new UserDto();
    userDto.setUsername("dsf");
    userDto.setPassword("dsf");

    URL url = new URL("http://localhost:8080/home/property");
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("POST");

        conn.setDoInput(true);
        conn.setDoOutput(true);

        conn.setConnectTimeout(1000);
        conn.setReadTimeout(1000);
        OutputStream os = conn.getOutputStream();

        JAXBContext jc = JAXBContext.newInstance(userDto.getClass()); 
        try {
            jc.createMarshaller().marshal(userDto, os);
        }
        catch(Exception ex){
            ex.printStackTrace();
        }



        os.flush();

But its not working. I'm getting a null value at the services end.

Answer 1

You need to encode your object suitably (usually XML or JSON) to send it over the stream.

        JAXBContext jc = JAXBContext.newInstance(obj.getClass()); 
        try ( OutputStream xml = connection.getOutputStream()) {
            jc.createMarshaller().marshal(obj, xml);   
        }

Make sure you do:

        connection.setRequestMethod("POST");
        connection.setDoOutput(true);
        connection.setRequestProperty("Content-Type", "application/xml");

Before writing anything to the stream.

Your web service method should look like this:

@RequestMapping(value = "URLHere", method = RequestMethod.POST)
public String postGroupBody(
        @RequestBody ObjectType object,
        otherParamsHere) {

Answer 2

You can use RestTemplate from spring to call these services.

String url = "http://localhost:8080/home/property";
UserDto userDto = new UserDto();
userDto.setUsername("dsf");
userDto.setPassword("dsf");

RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<UserDto> entity = new HttpEntity<UserDto>(userDto,headers);

ResponseEntity<ReturnedObject> result = restTemplate.exchange(url, HttpMethod.POST, entity, ReturnedObject.class);
ReturnedObject obj = result.getBody();

// you will get object returned by service in result.getBody();

Since you have not mentioned your service request format, I am assuming it's JSON, And you are using Jackson mapper to convert object to JSON and vice versa.

Answer 3

I guess you need to use @RequestBody instead of @ModelAttribute for your UserDto parameter.