创建请求

创建请求头：

Map<String, String> requestBody = new HashMap<>();
requestBody.put("userId", userId);
requestBody.put("userName", userName);

创建请求体：

HttpHeaders requestHeader = new HttpHeaders();
requestHeader.add("cookie", "cookie");
requestHeader.add("userInfo", "{userId:101,userName:userName}");

创建请求方式：

HttpEntity<Map<String, String>> httpEntity = new HttpEntity<>(requestHeader);
RestTemplate restTemplate = new RestTemplate();

POST请求

restTemplate发送POST请求时可以通过如下方法获取ResponseEntity：

ResponseEntity responseEntity = restTemplate.postForEntity(url, httpEntity, JSONObject.class);

或用以下方法获取jsonObject：

JSONObject jsonObject = restTemplate.postForObject(url, httpEntity, JSONObject.class);

GET请求

GET请求没有相应的方法，只能用exchange方法获取ResponseEntity：

ResponseEntity<JSONObject> responseEntity = restTemplate.exchange(url, HttpMethod.GET, httpEntity, JSONObject.class, requestBody);

若出现如下报错：

Not enough variables available to expand

则是因为RestTemplate认为大括号{}为占位符，需要将请求头中的{userId:101,userName:userName}改为{\"userId\":\"101\",\"userName\":\"userName\"}