RestTemplate中post請求實用分析

1、最近在做相關平台對接工作。對接第一步需要在後端完成認證，拿到對方平台的access_token。由于對方文檔不是很詳細，根據認證需要的參數進行了多種嘗試。順帶學習一下RestTemplate發post的請求的各種姿勢。記錄在此，以便檢視。

2、往後端發post請求一般分為兩種，

一種是普通的表單送出(Content-Type: application/x-www-form-urlencoded)。

另一種是JSON送出(Content-Type: application/json)。

當然背景接收的方式也不同，

普通表單送出從request.getParameter()就能擷取。

JSON送出的的資料在io流中，可以通過request.getInputStream()擷取。spring為我們提供了@RequestBody注解，簡單易用。

3、了解上述内容之後，下面進行試驗

①模拟表單送出(要知道，post請求也可以使用url傳參奧)

/**
 * 1、使用uri傳參形式，把參數拼接到url後面，并在占位符裡給每個參數指派一定意義的名字。然後把參數封裝到 
 * Map中。 占位符中的參數名會去對應Map中的key找到參數的值以完成替換。
 * 傳參并攜帶請求頭
 */
 @GetMapping("/auth1")
    public void auth1() {
        try {
            Map uriVariables = new LinkedHashMap(4);
            uriVariables.put("username", "name");
            uriVariables.put("password", "1234");
            uriVariables.put("type", "client");
            uriVariables.put("grant_type", "password");
            HttpHeaders headers = new HttpHeaders();
            headers.add("Authorization", "Basic aW90OmlvdA==");
            HttpEntity httpEntity = new HttpEntity(null, headers);
            ResponseEntity<String> entity = restTemplate.postForEntity("http://192.168.1.111:8086/auth/server?username={username}&password={password}&type={type}&grant_type={grant_type}", httpEntity, String.class, uriVariables);
            if (entity.getStatusCode().is2xxSuccessful()) {
                System.out.println(entity.getBody());
            } else {
                log.error("認證失敗:[{}]", entity);
            }
        } catch (Exception e) {
            log.error("認證異常:[{}]", e.getMessage());
        }
    }

/**
 * 2、使用uri傳參形式，把參數拼接到url後面，在占位符裡寫上參數的索引位置。然後把參數放在可變長變量中。
 * 實際參數會根據參數索引位置完成替換
 * 傳參并攜帶請求頭
 */
    @GetMapping("/auth2")
    public void auth2() {
        try {
            final String username = "name";
            final String password = "1234";
            final String type = "client";
            final String grant_type = "password";
            HttpHeaders headers = new HttpHeaders();
            headers.add("Authorization", "Basic aW90OmlvdA==");
            HttpEntity httpEntity = new HttpEntity(null, headers);
            ResponseEntity<String> entity = restTemplate.postForEntity("http://192.168.1.111:8086/auth/server?username={0}&password={1}&type={2}&grant_type={3}", httpEntity, String.class, username, password, type, grant_type);
            if (entity.getStatusCode().is2xxSuccessful()) {
                System.out.println(entity.getBody());
            } else {
                log.error("認證失敗:[{}]", entity);
            }
        } catch (Exception e) {
            log.error("認證異常:[{}]", e.getMessage());
        }
    }

/**
 * 3、把參數封裝到LinkedMultiValueMap中，使用HttpEntity一并封裝表單資料和請求頭
 * 傳參并攜帶請求頭
 */
    @GetMapping("/auth3")
    public void auth3() {
        try {
            MultiValueMap body = new LinkedMultiValueMap(4);
            body.add("username", "name");
            body.add("password", "1234");
            body.add("type", "client");
            body.add("grant_type", "password");
            HttpHeaders headers = new HttpHeaders();
            headers.add("Authorization", "Basic aW90OmlvdA==");
            HttpEntity httpEntity = new HttpEntity(body, headers);
            ResponseEntity<String> entity = restTemplate.postForEntity("http://192.168.1.111:8086/auth/server", httpEntity, String.class);
            if (entity.getStatusCode().is2xxSuccessful()) {
                System.out.println(entity.getBody());
            } else {
                log.error("認證失敗:[{}]", entity);
            }
        } catch (Exception e) {
            log.error("認證異常:[{}]", e.getMessage());
        }
    }


/**
 * 4、把參數封裝到LinkedMultiValueMap中，隻發送表單資料可以不使用HttpEntity 
 * 傳參不攜帶請求頭
 */
    @GetMapping("/auth4")
    public void auth4() {
        try {
            MultiValueMap body = new LinkedMultiValueMap(4);
            body.add("username", "name");
            body.add("password", "1234");
            body.add("type", "client");
            body.add("grant_type", "password");
            ResponseEntity<String> entity = restTemplate.postForEntity("http://192.168.1.111:8086/auth/server", body, String.class);
            if (entity.getStatusCode().is2xxSuccessful()) {
                System.out.println(entity.getBody());
            } else {
                log.error("認證失敗:[{}]", entity);
            }
        } catch (Exception e) {
            log.error("認證異常:[{}]", e.getMessage());
        }
    }

②JSON送出的形式

/**
   * 5、資料可以用map封裝、可以用實體類封裝、也可以是json格式的字元串
   *    攜帶請求頭
   */
    @GetMapping("/auth5")
    public void auth5() {
        try {
            Map body = new LinkedHashMap(4);
            body.put("username", "name");
            body.put("password", "1234");
            body.put("type", "client");
            body.put("grant_type", "password");
            HttpHeaders headers = new HttpHeaders();
            headers.add("Authorization", "Basic aW90OmlvdA==");
            HttpEntity httpEntity = new HttpEntity(body, headers);
            ResponseEntity<String> entity = restTemplate.postForEntity("http://192.168.1.111:8086/auth/server2", httpEntity, String.class);
            if (entity.getStatusCode().is2xxSuccessful()) {
                System.out.println(entity.getBody());
            } else {
                log.error("認證失敗:[{}]", entity);
            }
        } catch (Exception e) {
            log.error("認證異常:[{}]", e.getMessage());
        }
    }

  /**
   * 5、資料可以用map封裝、可以用實體類封裝、也可以是json格式的字元串
   *    不攜帶請求頭
   */
    @GetMapping("/auth6")
    public void auth6() {
        try {
            Map body = new LinkedHashMap(4);
            body.put("username", "name");
            body.put("password", "1234");
            body.put("type", "client");
            body.put("grant_type", "password");
            ResponseEntity<String> entity = restTemplate.postForEntity("http://192.168.1.111:8086/auth/server2", body, String.class);
            if (entity.getStatusCode().is2xxSuccessful()) {
                System.out.println(entity.getBody());
            } else {
                log.error("認證失敗:[{}]", entity);
            }
        } catch (Exception e) {
            log.error("認證異常:[{}]", e.getMessage());
        }
    }

4、附上背景接收代碼

@PostMapping("/server")
    public String server(String username, String password, String type, String grant_type, HttpServletRequest request) {
        System.out.println(username);
        System.out.println(password);
        System.out.println(type);
        System.out.println(grant_type);

        String header = request.getHeader("Authorization");
        System.out.println(header);

        return "ok";
    }

    @PostMapping("/server2")
    public String server(@RequestBody Object obj, HttpServletRequest request) {
        System.out.println(obj);

        String header = request.getHeader("Authorization");
        System.out.println(header);

        return "ok";
    }

5、最後附上抓包資料，可以清楚的觀察到資料的傳送格式以及Content-Type的形式

POST /auth/server?username=name&password=1234&type=client&grant_type=password HTTP/1.1
Accept: text/plain, application/json, application/*+json, */*
Authorization: Basic aW90OmlvdA==
Content-Length: 0
Host: 192.168.1.111:8086
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.5.8 (Java/1.8.0_131)
Accept-Encoding: gzip,deflate


POST /auth/server?username=name&password=1234&type=client&grant_type=password HTTP/1.1
Accept: text/plain, application/json, application/*+json, */*
Authorization: Basic aW90OmlvdA==
Content-Length: 0
Host: 192.168.1.111:8086
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.5.8 (Java/1.8.0_131)
Accept-Encoding: gzip,deflate


POST /auth/server HTTP/1.1
Accept: text/plain, application/json, application/*+json, */*
Authorization: Basic aW90OmlvdA==
Content-Type: application/x-www-form-urlencoded;charset=UTF-8
Content-Length: 59
Host: 192.168.1.111:8086
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.5.8 (Java/1.8.0_131)
Accept-Encoding: gzip,deflate

username=name&password=1234&type=client&grant_type=password


POST /auth/server HTTP/1.1
Accept: text/plain, application/json, application/*+json, */*
Content-Type: application/x-www-form-urlencoded;charset=UTF-8
Content-Length: 59
Host: 192.168.1.111:8086
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.5.8 (Java/1.8.0_131)
Accept-Encoding: gzip,deflate

username=name&password=1234&type=client&grant_type=password


POST /auth/server2 HTTP/1.1
Accept: text/plain, application/json, application/*+json, */*
Authorization: Basic aW90OmlvdA==
Content-Type: application/json;charset=UTF-8
Content-Length: 77
Host: 192.168.1.111:8086
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.5.8 (Java/1.8.0_131)
Accept-Encoding: gzip,deflate

{"username":"name","password":"1234","type":"client","grant_type":"password"}


POST /auth/server2 HTTP/1.1
Accept: text/plain, application/json, application/*+json, */*
Content-Type: application/json;charset=UTF-8
Content-Length: 77
Host: 192.168.1.111:8086
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.5.8 (Java/1.8.0_131)
Accept-Encoding: gzip,deflate

{"username":"name","password":"1234","type":"client","grant_type":"password"}

6、總結：

在做平台對接的時候，一開始使用的是第三種形式發送post請求。經過一番調試，沒有認證成功。但是我通過postman請求是成功的。通過抓包，發現postman發送資料的形式是前面兩種形式，即把參數放在url上。後來在程式中切換到前兩種形式，成功認證并擷取到對方平台的accessToken。由于不知道對方代碼的實作方式，故無法進一步分析。

在我的試驗中以前三種形式進行表單送出都能正常擷取到資料，若今後遇到類似問題，要做到舉一反三、觸類旁通。

7、小尾巴~~

隻要有積累，就會有進步

RestTemplate中post請求實用分析

RestTemplate中post請求實用分析

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