●exchange方法提供统一的方法模板进行四种请求：POST,PUT,DELETE,GET
(1)POST请求
String reqJsonStr = "{\"code\":\"testCode\", \"group\":\"testGroup\",\"content\":\"testContent\", \"order\":1}";
HttpHeaders headers = new HttpHeaders(); headers.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<String> entity = new HttpEntity<String>(reqJsonStr,headers);
ResponseEntity<Map> resp = restTemplate.exchange(DIC_DATA_URL, HttpMethod.POST, entity, Map.class);
(2)PUT请求
String reqJsonStr = "{\"id\":227,\"code\":\"updateCC\", \"group\":\"UPDATE\",\"content\":\"updateCT\", \"order\":9}";
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<String> entity = new HttpEntity<String>(reqJsonStr,headers);
ResponseEntity<Map> resp = restTemplate.exchange(DIC_DATA_URL, HttpMethod.PUT, entity, Map.class);
(3)DELETE请求
ResponseEntity<Map> resp = restTemplate.exchange(DIC_DATA_URL + "?id={id}", HttpMethod.DELETE, null, Map.class, 227);
(4)GET请求
ResponseEntity<String> results = restTemplate.exchange(url,HttpMethod.GET, null, String.class, params);
说明：1）url: 请求地址； 2）method: 请求类型(如：POST,PUT,DELETE,GET)； 3）requestEntity: 请求实体，封装请求头，请求内容 4）responseType: 响应类型，根据服务接口的返回类型决定 5）uriVariables: url中参数变量值
Spring RestTemplate 之exchange方法
原文：https://www.cnblogs.com/jnba/p/10522608.html