Send a String to a Spring(Jackson) REST controller in a POST method

Question

I am attempting to send a String object to a rest service using HTTP Post method. and the String should be sent in the request body.

The controller

@RestController
@RequestMapping(value = "post", method = RequestMethod.POST)
public class HttpMethodPostController {

    /*HttpClientErrorException: 415 null*/
    @RequestMapping(value = "/string_as_text", consumes = MediaType.TEXT_PLAIN_VALUE)
    public ResponseEntity<Void> getStringAsText(@RequestBody String text) {
        System.out.println("[Server] text = " + text);
        return new ResponseEntity<Void>(HttpStatus.OK);
    }

    /*HttpClientErrorException: 400 null*/
    @RequestMapping(value = "/string_as_json", consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
    public ResponseEntity<Void> getStringAsJSON(@RequestBody String text) {
        System.out.println("[Server] text = " + text);
        return new ResponseEntity<Void>(HttpStatus.OK);
    }

    @RequestMapping(value = "/type1_", consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
    public ResponseEntity<Void> postType1_(@RequestBody Type1_ type1_) {
        System.out.println("[Server] type1_ = " + type1_);
        return new ResponseEntity<Void>(HttpStatus.OK);
    }

}

The consumer

public class HttpMethodPostConsumer {
    public static final String POST_ADDRESS = "http://localhost:55055/post";

    /*HttpClientErrorException: 415 null*/
    public static void postStringAsText(String text) {
        final RestTemplate restTemplate = new RestTemplate();
        final HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.TEXT_PLAIN);
        final HttpEntity<String> entity = new HttpEntity<>(text, headers);
        final URI uri = restTemplate.postForLocation(POST_ADDRESS + "/string_as_text", entity, String.class);
        System.out.println("uri = " + uri);
    }

    /*HttpClientErrorException: 400 null*/
    public static void postStringAsJSON(String text) {
        final RestTemplate restTemplate = new RestTemplate();
        final HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
        final HttpEntity<String> entity = new HttpEntity<>(text, headers);
        final URI uri = restTemplate.postForLocation(POST_ADDRESS + "/string_as_json", entity, String.class);
        System.out.println("uri = " + uri);
    }

    public static void postType1_(Type1_ type1_) {
        final RestTemplate restTemplate = new RestTemplate();
        final HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
        final HttpEntity<Type1_> httpEntity = new HttpEntity<Type1_>(type1_, headers);
        final URI result_URI = restTemplate.postForLocation(POST_ADDRESS + "/type1_", httpEntity, Type1_.class);
        System.out.println("result_URI = " + result_URI);
    }
}

The consumer test runner

public class HttpMethodPostConsumerTest {

    /*HttpClientErrorException: 415 null*/
    @Test
    public void test_postStringAsText() {
        final String text = Randomizers.getString();
        System.out.println("text = " + text);
        postStringAsText(text);
    }

    /*HttpClientErrorException: 400 null*/
    @Test
    public void test_postStringAsJSON() {
        final String text = Randomizers.getString();
        System.out.println("text = " + text);
        postStringAsJSON(text);
    }

    @Test
    public void test_postType1_() {
        final Type1_ type1_ = ModelFactory.getType1_();
        System.out.println("[Consumer] type1_ = " + type1_);
        postType1_(type1_);
    }

}

The Testing Procedure

The server is run first (http://localhost:55055/)
Wait until the server is up and running.
Run test_postType1_() will work as expected.
Run test_postStringAsText() Will result in client/consumer side error

org.springframework.web.client.HttpClientErrorException: 415 null

at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:94) at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:79) at org.springframework.web.client.ResponseErrorHandler.handleError(ResponseErrorHandler.java:63) at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:775) at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:728) at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:684) at org.springframework.web.client.RestTemplate.postForLocation(RestTemplate.java:405) at personal.learn.java.spring_rest.rest_general.non_automated.consumers.HttpMethodPostConsumer.postStringAsText(HttpMethodPostConsumer.java:21) at personal.learn.java.spring_rest.rest_general.non_automated.consumers.HttpMethodPostConsumerTest.test_postStringAsText(HttpMethodPostConsumerTest.java:17)

Run test_postStringAsJSON() will result in errors
- Client/consumer side error

org.springframework.web.client.HttpClientErrorException: 400 null

at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:94) at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:79) at org.springframework.web.client.ResponseErrorHandler.handleError(ResponseErrorHandler.java:63) at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:775) at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:728) at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:684) at org.springframework.web.client.RestTemplate.postForLocation(RestTemplate.java:405) at personal.learn.java.spring_rest.rest_general.non_automated.consumers.HttpMethodPostConsumer.postStringAsJSON(HttpMethodPostConsumer.java:31) at personal.learn.java.spring_rest.rest_general.non_automated.consumers.HttpMethodPostConsumerTest.test_postStringAsJSON(HttpMethodPostConsumerTest.java:25)

Server side error (In console)

02-May-2018 17:25:45.469 WARNING [http-nio-55055-exec-2] org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.handleHttpMessageNotReadable Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Unrecognized token 'IAtQDIxTCh': was expecting 'null', 'true', 'false' or NaN; nested exception is com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'IAtQDIxTCh': was expecting 'null', 'true', 'false' or NaN at [Source: (PushbackInputStream); line: 1, column: 21]

Server side error (In Tomcat Catalina Log)

02-May-2018 17:25:45.469 WARNING [http-nio-55055-exec-2] org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.handleHttpMessageNotReadable Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Unrecognized token 'IAtQDIxTCh': was expecting 'null', 'true', 'false' or NaN; nested exception is com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'IAtQDIxTCh': was expecting 'null', 'true', 'false' or NaN at [Source: (PushbackInputStream); line: 1, column: 21]

A trivial question. Is the controller up and running in a server before invoking the post request from the PostConsumer? — Amal
How is the server configured to use port 55055? Is debug enabled? What do the logs say? — Andrew S
Yes. I run the server first then run the consumer as a JUnit test. — sero
I am going to update the question to include more relevant data. — sero
did you tried using external client like postman as well? that'll filter out whether you have client side or server side issue. — Shanu Gupta

lintz11 lintz11 · Accepted Answer · 2018-05-02T14:41:00

If you want to POST to your server using @RequestBody, it's necessary send a object to your controller.

Create a DTO class with your String param:

public class ExampleDTO {

 private String stringExample;

  public String getStringExample() {
    return stringExample;
  }

  public void setStringExample(String stringExample) {
    this.stringExample= stringExample;
  }

}

Your controller:

@RequestMapping(method = RequestMethod.POST, value = "/string_as_text")
public ResponseEntity<Void> getStringAsText(@RequestBody ExampleDTO exampleDTO) {
    System.out.println("[Server] text = " + exampleDTO.getStringExample());
    return new ResponseEntity<Void>(HttpStatus.OK);
}

The consumer

ExampleDTO param = new ExampleDTO();
param.setStringExample("text")

Send a String to a Spring(Jackson) REST controller in a POST method

1 Answers