Curl POST command to pass json data to spring-boot app not working

Question

Have looked at other related posts but nothing seemed to work.

Basically I'm trying to figure out how to pass data to my restful spring-boot app.

Here is the curl command I'm using:

$ curl -iX POST -H 'Content-Type: application/json' -d @args.json http://localhost:8080/myapp/dummyApi

With args.json contains:

file: args.json:

{
 "arg1": "hello",
 "arg2": 10, 
 "arg3": {
 "a": "1",
 "b": "2" 
 }
}

The api is defined in MyController.java as such:

file: MyController.java

@RestController
@RequestMapping("/myapp")
public class MyController {
//...
static class DummyRet {
 private String foo;
 public DummyRet(String f) {
 foo = f;
 }
 public String getFoo() {
 return foo;
 }
 public void setFoo(String foo) {
 this.foo = foo;
 }
}
@RequestMapping(value="/dummyApi", method=RequestMethod.POST)
public DummyRet dummyApi(@RequestParam(value = "arg1", required = false, defaultValue = "") String arg1,
 @RequestParam(value = "arg2", required = false, defaultValue = "") Long arg2,
 @RequestParam(value = "arg3", required = false) Map<String, String> arg3) {
 LOGGER.info(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
 LOGGER.info("Arguments received:");
 LOGGER.info("arg1: " + arg1);
 LOGGER.info("arg2: " + arg2);
 LOGGER.info("arg3: " + arg3);
 LOGGER.info(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
 return new DummyRet("foo");
}
//...
}

The return of the curl command is 200 success (since non of the arguments is required) but the values of args are not reaching over to dummyApi method

$ curl -iX POST -H 'Content-Type: application/json' -d @args.json http://localhost:8080/myapp/dummyApi
HTTP/1.1 200 
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Date: 2017年6月04日 15:37:42 GMT
{"foo":"foo"}

The server console looks like this:

2017年06月04日 18:17:56.818 DEBUG 32258 --- [nio-8080-exec-7] o.s.web.servlet.DispatcherServlet : DispatcherServlet with name 'dispatcherServlet' processing POST request for [/myapp/dummyApi]
2017年06月04日 18:17:56.818 DEBUG 32258 --- [nio-8080-exec-7] s.w.s.m.m.a.RequestMappingHandlerMapping : Looking up handler method for path /myapp/dummyApi
2017年06月04日 18:17:56.818 DEBUG 32258 --- [nio-8080-exec-7] s.w.s.m.m.a.RequestMappingHandlerMapping : Returning handler method [public com.xx.controllers.MyController$DummyRet com.xx.controllers.MyController.dummyApi(java.lang.String,java.lang.Long,java.util.Map<java.lang.String, java.lang.String>)]
2017年06月04日 18:17:56.819 INFO 32258 --- [nio-8080-exec-7] c.p.controllers.MyController : >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
2017年06月04日 18:17:56.819 INFO 32258 --- [nio-8080-exec-7] c.p.controllers.MyController : Arguments received:
2017年06月04日 18:17:56.819 INFO 32258 --- [nio-8080-exec-7] c.p.controllers.MyController : arg1: 
2017年06月04日 18:17:56.819 INFO 32258 --- [nio-8080-exec-7] c.p.controllers.MyController : arg2: null
2017年06月04日 18:17:56.819 INFO 32258 --- [nio-8080-exec-7] c.p.controllers.MyController : arg3: null
2017年06月04日 18:17:56.819 INFO 32258 --- [nio-8080-exec-7] c.p.controllers.MyController : >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
2017年06月04日 18:17:56.819 DEBUG 32258 --- [nio-8080-exec-7] m.m.a.RequestResponseBodyMethodProcessor : Written [com.xx.controllers.MyController$DummyRet@c35d46f] as "application/json" using [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter@301ec38b]
2017年06月04日 18:17:56.819 DEBUG 32258 --- [nio-8080-exec-7] o.s.web.servlet.DispatcherServlet : Null ModelAndView returned to DispatcherServlet with name 'dispatcherServlet': assuming HandlerAdapter completed request handling
2017年06月04日 18:17:56.819 DEBUG 32258 --- [nio-8080-exec-7] o.s.web.servlet.DispatcherServlet : Successfully completed request

I hope I haven't left out any of the important details, but please let me know if anything is missing.

Answer 1

This worked:

I had two issues in my spring-boot java method,

1. I'm specifying @RrequestParam for the arguments, where I should be using @RequestBody instead
2. I have multiple of such method params where in POST it should be a single (see footnote) @RequestBody

But since I need to pass multiple arguments over to the method the solution was to wrap these arguments in a backing object, as such:

public static class Args {
 // members
 private String arg1;
 private Long arg2;
 private Map<String, String> arg3;
 // accessors
 public String getArg1() {return arg1;}
 public void setArg1(String arg1) {this.arg1 = arg1;}
 public Long getArg2() {return arg2;}
 public void setArg2(Long arg2) {this.arg2 = arg2;}
 public Map<String, String> getArg3() {return arg3;}
 public void setArg3(Map<String, String> arg3) {this.arg3 = arg3;}
}

The receiver method would then be:

@RequestMapping(value="/dummyApi", method=RequestMethod.POST)
public DummyRet dummyApi(@RequestBody Args args) {
 LOGGER.info(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
 LOGGER.info("Arguments received:");
 LOGGER.info("arg1: " + args.getArg1().toString());
 LOGGER.info("arg2: " + args.getArg2().toString());
 LOGGER.info("arg3: " + args.getArg3().toString());
 LOGGER.info(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
 return new DummyRet("foo");
}

Footnote: In fact it is possible to pass multiple params through custom implementation as described in this SO response. Haven't tried it

Answer 2

Refer below sample,

curl -H "Content-Type: application/json" --data @body.json 
http://localhost:8080/ui/webapp/conf

• has981: thanks for the suggestion but I still get the same behaviour as before
• RoshanKumar Mutha: Can you try with chrome postman extension? If you are able to get response using any post client such as postman then curl should also work as it is a client. PostMan : chrome.google.com/webstore/detail/postman/…
• has981: sorry for the delay, just tried chrome postman, still getting same behaviour, to make sure I'm not using anything funny in my spring boot app I cloned spring-boot-tutorial. Only added code related to dummyApi
• has981: unfortunately no :(
• has981: Let us continue this discussion in chat.