RestTemplate中post请求实用分析

矫情吗；* 2023-02-20 04:46 51阅读 0赞

### RestTemplate中post请求实用分析 ###

> 1、最近在做相关平台对接工作。对接第一步需要在后端完成认证，拿到对方平台的access\_token。由于对方文档不是很详细，根据认证需要的参数进行了多种尝试。顺带学习一下RestTemplate发post的请求的各种姿势。记录在此，以便查看。

> 2、往后端发post请求一般分为两种，  
> 一种是普通的表单提交(Content-Type: application/x-www-form-urlencoded)。  
> 另一种是JSON提交(Content-Type: application/json)。  
> 当然后台接收的方式也不同，  
> 普通表单提交从request.getParameter()就能获取。  
> JSON提交的的数据在io流中，可以通过request.getInputStream()获取。spring为我们提供了@RequestBody注解，简单易用。

> 3、了解上述内容之后，下面进行试验  
> ①模拟表单提交(要知道，post请求也可以使用url传参奥)

/** * 1、使用uri传参形式，把参数拼接到url后面，并在占位符里给每个参数赋值一定意义的名字。然后把参数封装到 * Map中。 占位符中的参数名会去对应Map中的key找到参数的值以完成替换。 * 传参并携带请求头 */
     @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("认证失败:[{}]", entity);
                }
            } catch (Exception e) { 
                log.error("认证异常:[{}]", e.getMessage());
            }
        }
    
    /** * 2、使用uri传参形式，把参数拼接到url后面，在占位符里写上参数的索引位置。然后把参数放在可变长变量中。 * 实际参数会根据参数索引位置完成替换 * 传参并携带请求头 */
        @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("认证失败:[{}]", entity);
                }
            } catch (Exception e) { 
                log.error("认证异常:[{}]", e.getMessage());
            }
        }
    
    /** * 3、把参数封装到LinkedMultiValueMap中，使用HttpEntity一并封装表单数据和请求头 * 传参并携带请求头 */
        @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("认证失败:[{}]", entity);
                }
            } catch (Exception e) { 
                log.error("认证异常:[{}]", e.getMessage());
            }
        }
    
    
    /** * 4、把参数封装到LinkedMultiValueMap中，只发送表单数据可以不使用HttpEntity * 传参不携带请求头 */
        @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("认证失败:[{}]", entity);
                }
            } catch (Exception e) { 
                log.error("认证异常:[{}]", e.getMessage());
            }
        }

> ②JSON提交的形式

/** * 5、数据可以用map封装、可以用实体类封装、也可以是json格式的字符串 * 携带请求头 */
        @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("认证失败:[{}]", entity);
                }
            } catch (Exception e) { 
                log.error("认证异常:[{}]", e.getMessage());
            }
        }
    
      /** * 5、数据可以用map封装、可以用实体类封装、也可以是json格式的字符串 * 不携带请求头 */
        @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("认证失败:[{}]", entity);
                }
            } catch (Exception e) { 
                log.error("认证异常:[{}]", e.getMessage());
            }
        }

> 4、附上后台接收代码

@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、最后附上抓包数据，可以清楚的观察到数据的传送格式以及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、总结：  
> 在做平台对接的时候，一开始使用的是第三种形式发送post请求。经过一番调试，没有认证成功。但是我通过postman请求是成功的。通过抓包，发现postman发送数据的形式是前面两种形式，即把参数放在url上。后来在程序中切换到前两种形式，成功认证并获取到对方平台的accessToken。由于不知道对方代码的实现方式，故无法进一步分析。  
> 在我的试验中以前三种形式进行表单提交都能正常获取到数据，若今后遇到类似问题，要做到举一反三、触类旁通。

> 7、小尾巴~~  
> 只要有积累，就会有进步