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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

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 provideGet(){        return myService.provideGet();    }    // 提供post接口    @PostMapping("/providePost")    public Map 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 providePostByMap(@RequestParam Map map) {        return myService.providePostByMap(map);    }    // 调用get接口    @GetMapping("/useGet")    public Map useGet() {        return myService.useGet();    }}

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1.2 Service

@Service@EnableSchedulingpublic class MyService {    public Map provideGet() {        Map res = new HashMap<>();        res.put("number", "3");        res.put("name", "张三get");        System.out.println("provideGet res:" + res + "\n");        return res;    }    public Map providePost(int number, String name) {        Map res = new HashMap<>();        res.put("number", number);        res.put("name", name);        return res;    }    public Map providePostByMap(Map 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 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 useGet() {        return myService.useGet();    }    // 调用get接口验证账号密码    @GetMapping("/useGetByPsw")    public Map useGetByPsw() {        return myService.useGetByPsw();    }    // 调用post接口    @PostMapping("/usePost")    public Map 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 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 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 responseData = restTemplate.getForEntity(getURL, ResponseResult.class);        Map 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 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 responseData = restTemplate.getForEntity(getURL, ResponseResult.class);        Map 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 usePost() {        //RestTemplate在postForObject时，用MultiValueMap，不可使用HashMap。        MultiValueMap 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 responseData = restTemplate.postForEntity(postURL, sendData, ResponseResult.class);        Map 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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