Java 中 restTemplate 的使用

作者：代码的路

2023-01-13
江苏
本文字数：2901 字
阅读完需：约 10 分钟

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本文介绍 restTemplate 基础用法。

Java 中 get 和 post 的用法请参考：https://mp.weixin.qq.com/s/mC0D1nuCqIori5bWtLorWQ

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();    }}

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1.2 Service

@Service@EnableSchedulingpublic 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;    }}

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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();    }}

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2.2 Service

@Service@EnableSchedulingpublic 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 strObject = restTemplate.getForObject(getURL, 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.getForEntity(getURL, ResponseResult.class);        Map<String, Object> returnData = new HashMap<>();        returnData.put("StatusCode:", responseData.getStatusCode());        returnData.put("Body:", responseData.getBody());
        System.out.println("useGet jsonObject:" + jsonObject + "\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;    }}