Java中restTemplate的使用

Love The Way You Lie 2023-09-23 15:10 99阅读 0赞

[原文链接][Link 1]

[GitHub项目地址][GitHub]

[Gitee项目地址][Gitee]

本文介绍restTemplate基础用法。

Java中get和post的用法请参考：[Java中Get和Post的使用][Java_Get_Post]

## 1 提供get/post接口 ##

### 1.1 Controller ###

@RestController
    @RequestMapping("/homepage")
    public class MyController {
        
    
        @Autowired
        MyService myService;
    
        // 提供get接口
        @GetMapping("/provideGet")
        public Map<String, String> provideGet(){
        
            return myService.provideGet();
        }
    
        // 提供post接口
        @PostMapping("/providePost")
        public Map<String, Object> providePost(@RequestParam("number") int number, @RequestParam("name") String name) {
        
            return myService.providePost(number, name);
        }
    
        // 提供map参数的post接口
        @PostMapping("/providePostByMap")
        public Map<String, Object> providePostByMap(@RequestParam Map<String, Object> map) {
        
            return myService.providePostByMap(map);
        }
    
        // 调用get接口
        @GetMapping("/useGet")
        public Map<String, Object> useGet() {
        
            return myService.useGet();
        }
    }

### 1.2 Service ###

@Service
    @EnableScheduling
    public class MyService {
        
    
        public Map<String, String> provideGet() {
        
            Map<String, String> res = new HashMap<>();
            res.put("number", "3");
            res.put("name", "张三get");
            System.out.println("provideGet res:" + res + "\n");
            return res;
        }
    
        public Map<String, Object> providePost(int number, String name) {
        
            Map<String, Object> res = new HashMap<>();
            res.put("number", number);
            res.put("name", name);
    
            return res;
        }
    
        public Map<String, Object> providePostByMap(Map<String, Object> map) {
        
            int number = map.get("number") == null ? 0 : Integer.parseInt((String) map.get("number"));
            String name = map.get("name") == null ? "" : (String) map.get("name");
            Map<String, Object> res = new HashMap<>();
            res.put("number", number);
            res.put("name", name);
    
            System.out.println("providePostByMap res:" + res + "\n");
            return res;
        }
    }

## 2 调用get/post接口 ##

使用restTemplate调用get/post接口。

*  `getForObject()`:返回值是`HTTP`协议的响应体
 *  `getForEntity()`:返回的是`ResponseEntity`，`ResponseEntity`是对`HTTP`响应的封装，除了包含响应体，还包含`HTTP`状态码、`contentType、contentLength、Header`等信息

### 2.1 Controller ###

@RestController
    @RequestMapping("/homepage")
    public class MyController {
            
    	@Autowired
        MyService myService;
    
        // 调用get接口
        @GetMapping("/useGet")
        public Map<String, Object> useGet() {
        
            return myService.useGet();
        }
    
        // 调用get接口验证账号密码
        @GetMapping("/useGetByPsw")
        public Map<String, Object> useGetByPsw() {
        
            return myService.useGetByPsw();
        }
    
        // 调用post接口
        @PostMapping("/usePost")
        public Map<String, Object> usePost() {
        
            return myService.usePost();
        }
    }

### 2.2 Service ###

@Service
    @EnableScheduling
    public class MyService {
        
        @Resource
        private RestTemplate restTemplate;
    
        String getURL = "http://localhost:8081/homepage/provideGet";
        String postURL = "http://localhost:8081/homepage/providePostByMap";
    
        public Map<String, Object> useGet() {
        
            // getForObject返回值是HTTP协议的响应体
            String strObject1 = restTemplate.getForObject(getURL, String.class); //无参
            JSONObject jsonObject1 = JSONObject.parseObject(strObject1);
    
            MultiValueMap<String, String> sendData = new LinkedMultiValueMap<>();
            sendData.add("number", "3");
            sendData.add("name", "张三post");
            String strObject2 = restTemplate.getForObject(getURL, String.class, sendData); // 带参
            JSONObject jsonObject2 = JSONObject.parseObject(strObject2);
    
            // getForEntity返回的是ResponseEntity，是对HTTP响应的封装
            ResponseEntity<ResponseResult> responseData = restTemplate.getForEntity(getURL, ResponseResult.class);
            Map<String, Object> returnData = new HashMap<>();
            returnData.put("StatusCode:", responseData.getStatusCode());
            returnData.put("Body:", responseData.getBody());
    
            System.out.println("useGet jsonObject1:" + jsonObject1 + "\n");
            System.out.println("useGet jsonObject2:" + jsonObject2 + "\n");
            System.out.println("useGet responseData:" + responseData + "\n");
            System.out.println("useGet returnData:" + returnData + "\n");
            return returnData;
        }
    
        public Map<String, Object> useGetByPsw() {
        
    
            RestTemplateBuilder builder = new RestTemplateBuilder();
            RestTemplate restTemplate = builder.basicAuthentication("username", "password").build();
    
            // getForEntity返回的是ResponseEntity，是对HTTP响应的封装
            ResponseEntity<ResponseResult> responseData = restTemplate.getForEntity(getURL, ResponseResult.class);
            Map<String, Object> returnData = new HashMap<>();
            returnData.put("StatusCode:", responseData.getStatusCode());
            returnData.put("Body:", responseData.getBody());
    
            System.out.println("useGetByPsw returnData:" + responseData + "\n");
            System.out.println("useGetByPsw returnData:" + returnData + "\n");
            return returnData;
        }
    
        public Map<String, Object> usePost() {
        
            //RestTemplate在postForObject时，用MultiValueMap，不可使用HashMap。
            MultiValueMap<String, String> sendData = new LinkedMultiValueMap<>();
            sendData.add("number", "3");
            sendData.add("name", "张三post");
    
            // getForObject返回值是HTTP协议的响应体
            String strObject = restTemplate.postForObject(postURL, sendData, String.class);
            JSONObject jsonObject = JSONObject.parseObject(strObject);
    
            // getForEntity返回的是ResponseEntity，是对HTTP响应的封装
            ResponseEntity<ResponseResult> responseData = restTemplate.postForEntity(postURL, sendData, ResponseResult.class);
            Map<String, Object> returnData = new HashMap<>();
            returnData.put("StatusCode:", responseData.getStatusCode());
            returnData.put("Body:", responseData.getBody());
    
            System.out.println("usePost jsonObject:" + jsonObject + "\n");
            System.out.println("usePost responseData:" + responseData + "\n");
            System.out.println("usePost returnData:" + returnData + "\n");
            return returnData;
        }
    }

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[代码的路][Link 2]

![bde0fcc7c7012e7004c022f2eaad98d2.png][]

[Link 1]: https://mp.weixin.qq.com/s/_GgxrTVTY92QHumXxWcUKw
[GitHub]: https://github.com/Snowstorm0/learn-restTemplate
[Gitee]: https://gitee.com/Snowstorm0/learn-restTemplate
[Java_Get_Post]: https://mp.weixin.qq.com/s/mC0D1nuCqIori5bWtLorWQ
[Link 2]: https://mp.weixin.qq.com/s/t0t89DFgJ1TEzI4uI5giHg
[bde0fcc7c7012e7004c022f2eaad98d2.png]: https://img-blog.csdnimg.cn/img_convert/bde0fcc7c7012e7004c022f2eaad98d2.png