Spring RestTemplate的使用与踩坑

引言

最近的项目需求中有使用到后端发送http请求，在网上寻找资料后发现可以使用spring自带的RestTemplate类实现，故作此记录

项目使用

将下述代码引入spring容器中（RestTemplate是spring自带的发送http请求的类）

@Bean
public RestTemplate restTemplate(ClientHttpRequestFactory factory) {
   RestTemplate restTemplate = new RestTemplate(factory);
   return restTemplate;
}
@Bean
public ClientHttpRequestFactory simpleClientHttpRequestFactory() {
   SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
   factory.setReadTimeout(5000);
   factory.setConnectTimeout(15000);
   // 设置代理
   //factory.setProxy(null);
   return factory;
}

在需要使用的类中直接引入即可

@Autowired
private RestTemplate restTemplate;

代码示例

这里简单示例下post请求，如果又其它需求的可以去搜索一下其它文章

**注意：**发送的post的传参的类型一定要是LinkedMultiValueMap（不能使用jsonobject），否则会报找不到数据的错误

@GetMapping("send")
public String testPost(@RequestParam("code") Integer code){
   String url = "http://localhost:8888/oauth/return";
   LinkedMultiValueMap<String, Object> stringObjectLinkedMultiValueMap = new LinkedMultiValueMap<>();
   stringObjectLinkedMultiValueMap.set("code",code);
   HttpEntity<LinkedMultiValueMap<String, Object>> jsonObjectHttpEntity = new HttpEntity<>(stringObjectLinkedMultiValueMap);
   ResponseEntity<String> stringResponseEntity = restTemplate.postForEntity(url, jsonObjectHttpEntity, String.class);
   String body = stringResponseEntity.getBody();
   return body;
}
@PostMapping("return")
public String returnPost(@RequestParam Integer code){
   return "哈首府帕斯发";
}

踩坑记录

发送POST请求传参的问题

如下代码，如果使用jsonobject来装载数据发送post请求是会报错的，只能使用LinkedMultiValueMap

@GetMapping("keycloak/getToken")
public String keycloakGetToken(@RequestParam Map<String,String> map){
   //String code = requestObj.getString("code");
   String url = "http://localhost:8081/auth/realms/myRealm/protocol/openid-connect/token";
   String code = map.get("code");
   System.out.println("传进来的code："+code);
   //HttpHeaders headers = new HttpHeaders();
   //JSONObject jsonObject = new JSONObject();
   //jsonObject.put("grant_type","authorization_code");
   //jsonObject.put("code",code);
   //jsonObject.put("client_id","myclient");
   //jsonObject.put("client_secret","LsvDoZ5g0BQhRDR9ydYqV9tjal8YDeAI");
   //jsonObject.put("scope","openid");
   //jsonObject.put("redirect_uri","http://localhost:8888/oauth/keycloak/getToken");
   //HttpEntity<JSONObject> jsonObjectHttpEntity = new HttpEntity<>(jsonObject,headers);
   LinkedMultiValueMap<String, Object> stringObjectLinkedMultiValueMap = new LinkedMultiValueMap<>();
   stringObjectLinkedMultiValueMap.set("grant_type","authorization_code");
   stringObjectLinkedMultiValueMap.set("code",code);
   stringObjectLinkedMultiValueMap.set("client_id","myclient");
   stringObjectLinkedMultiValueMap.set("client_secret","LsvDoZ5g0BQhRDR9ydYqV9tjal8YDeAI");
   stringObjectLinkedMultiValueMap.set("scope","openid");
   stringObjectLinkedMultiValueMap.set("redirect_uri","http://localhost:8888/oauth/keycloak/getToken");
   HttpEntity<LinkedMultiValueMap<String, Object>> jsonObjectHttpEntity = new HttpEntity<>(stringObjectLinkedMultiValueMap);
   ResponseEntity<String> responseEntity = restTemplate.postForEntity(url, jsonObjectHttpEntity, String.class);
   String body = responseEntity.getBody();
   return body;
}

来源：https://blog.csdn.net/qq_49137582/article/details/128768209