RestTemplate的学习使用

以你之姓@ 2023-09-23 22:57 62阅读 0赞

### 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 ###

1.  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;
        }
2.  在需要使用的类中直接引入即可
    
        @Autowired
        private RestTemplate restTemplate;
3.  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;
    }