How to properly send map from angular client to spring boot controller in request body? Received map is always empty

Question

Angular client - httpClient sending request

const map: Map<string, string> = new Map<string, string>();
map.set('foo', 'bar');
this.http.post(address, map, httpOptions).subscribe(
  next => console.log('next: ' + next),
  error => console.log('error: ' + error),
  () => console.log('complete')
);

Springboot server - controller receiving request

@RequestMapping(value = "/foobar", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE)
public void fooBar(@RequestBody Map<String, String> foo){
    System.out.println(foo.entrySet());  //<-- always empty
}

Ala A. · Accepted Answer · 2019-05-07 12:38:27Z

14

You have to convert the Map to an array of key-value pairs, as it turns out, Typescript maps cannot be used directly inside a http post body.

You can convert the map as follows:

const convMap = {};
map.forEach((val: string, key: string) => {
  convMap[key] = val;
});
this.http.post(apiBaseUrl + '/foobar', convMap, httpOptions).subscribe(
      next => console.log('next: ' + next),
      error => console.log('error: ' + error),
      () => console.log('complete')
);

In the back-end, your System.out.println(foo.entrySet()); will output the following: [foo=bar]

edited May 7, 2019 at 12:38

answered May 7, 2019 at 10:41

Ala A.

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2 Comments

hdw3 Over a year ago

JSON.stringify(map) and consumes="application/json" didn't help, still empty map

Shashi Ranjan Over a year ago

Typescript map not suitable for http post calls. I used directly the json data key value pair const postBody = {"data1":var1,"data2":var2} and it works like champ.

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