Spring Boot 中使用 HttpClient 进行 POST GET PUT DELETE

你的名字 2023-06-04 11:57 13阅读 0赞

有的时候，我们的 Spring Boot 应用需要调用第三方接口，这个接口可能是 Http协议、可能是 WebService、可能是 FTP或其他格式，本章讨论 Http 接口的调用。

通常基于 Http/Https 协议的接口请求动作 POST/GET/PUT/DELETE/PATCH 操作。交互的内容可以是文本、Json 或 Xml。

在 Spring Boot 中使用 Apache HttpClient 类库能够方便快捷地解决 Http 调用问题。

[本项目源码 github 下载][github]

# 1 新建 Spring Boot Maven 示例工程项目 #

注意：是用来 IDEA 开发工具

1.  File > New > Project，如下图选择 `Spring Initializr` 然后点击 【Next】下一步
2.  填写 `GroupId`（包名）、`Artifact`（项目名） 即可。点击 下一步  
    groupId=com.fishpro  
    artifactId=httpclient
3.  选择依赖 `Spring Web Starter` 前面打钩。
4.  项目名设置为 `spring-boot-study-httpclient`.

# 2 引入依赖 Pom #

<dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.3</version>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>

# 3 编写 HttpClient 代码示例 #

## 3.1 传统的 get/post ##

大多数情况，第三方提供的接口都是基于 GET/POST，而且一般需要设定 url、http head 的值，所以我们下面的代码是针对只有 GET/POST 的接口设定

/** * 传统的 http get/post 实现 * */ public class HttpClientUtils { /** * http get * @param url 可带参数的 url 链接 * @param heads http 头信息 * */ public String get(String url,Map<String,String> heads){ org.apache.http.client.HttpClient httpClient= HttpClients.createDefault(); HttpResponse httpResponse = null; String result=""; HttpGet httpGet=new HttpGet(url); if(heads!=null){ Set<String> keySet=heads.keySet(); for(String s:keySet){ httpGet.addHeader(s,heads.get(s)); } } try{ httpResponse=httpClient.execute(httpGet); HttpEntity httpEntity=httpResponse.getEntity(); if(httpEntity!=null){ result= EntityUtils.toString(httpEntity,"utf-8"); } }catch (IOException e){ e.printStackTrace(); } return result; } /** * http post * */ public static String post(String url, String data, Map<String, String> heads){ org.apache.http.client.HttpClient httpClient= HttpClients.createDefault(); HttpResponse httpResponse = null; String result=""; HttpPost httpPost=new HttpPost(url); if(heads!=null){ Set<String> keySet=heads.keySet(); for(String s:keySet){ httpPost.addHeader(s,heads.get(s)); } } try{ StringEntity s=new StringEntity(data,"utf-8"); httpPost.setEntity(s); httpResponse=httpClient.execute(httpPost); HttpEntity httpEntity=httpResponse.getEntity(); if(httpEntity!=null){ result= EntityUtils.toString(httpEntity,"utf-8"); } }catch (IOException e){ e.printStackTrace(); } return result; } }

调用也非常简单

## 3.2 基于 REST 接口的操作方法 ##

我们可以单独为 REST 风格接口提供方法，因为 HttpClient 为我们单独提供了针对 GET/POST/PUT/DELETE 的方法。

### 3.2.1 GET 方法 ###

1.  首先创建一个http请求 HttpGet httpGet=new HttpGet(url);
2.  自定义一个 Response Handler
3.  执行 httpclient.execute(请求，Handler)
4.  处理返回

/**
         * http get
         * @param url 可带参数的 url 链接
         * @param heads http 头信息
         * */
        public  static String get(String url,Map<String,String> heads){
            org.apache.http.client.HttpClient httpClient= HttpClients.createDefault();
            HttpResponse httpResponse = null;
            String result="";
            HttpGet httpGet=new HttpGet(url);
            if(heads!=null){
                Set<String> keySet=heads.keySet();
                for(String s:keySet){
                    httpGet.addHeader(s,heads.get(s));
                }
            }
    
            try{
    
                httpResponse=httpClient.execute(httpGet);
                HttpEntity httpEntity=httpResponse.getEntity();
                if(httpEntity!=null){
                    result= EntityUtils.toString(httpEntity,"utf-8");
    
                }
    
            }catch (IOException e){
                e.printStackTrace();
    
            }
            return  result;
        }

### 3.2.2 POST 方法 ###

1.  首先创建一个http请求 HttpPost httpPost = new HttpPost(url);
2.  自定义一个 Response Handler，向POST中添加数据（JSON 信息）和 Header信息
    
        httpPost.setHeader("Accept", "application/json"); httpPost.setHeader("Content-type", "application/json");
3.  执行 httpclient.execute(请求，Handler)
4.  处理返回

/** * post 方法 * @param url post 的 url * @param data 数据 application/json 的时候 为json格式 * @param heads Http Head 参数 * */ public static String post(String url,String data,Map<String,String> heads) throws IOException{ try (CloseableHttpClient httpclient = HttpClients.createDefault()) { HttpPost httpPost = new HttpPost(url); if(heads!=null){ Set<String> keySet=heads.keySet(); for(String s:keySet){ httpPost.addHeader(s,heads.get(s)); } } StringEntity stringEntity = new StringEntity(data); httpPost.setEntity(stringEntity); System.out.println("Executing request " + httpPost.getRequestLine()); // Create a custom response handler ResponseHandler < String > responseHandler = response -> { int status = response.getStatusLine().getStatusCode(); if (status >= 200 && status < 300) { HttpEntity entity = response.getEntity(); return entity != null ? EntityUtils.toString(entity) : null; } else { throw new ClientProtocolException("Unexpected response status: " + status); } }; String responseBody = httpclient.execute(httpPost, responseHandler); System.out.println("----------------------------------------"); System.out.println(responseBody); return responseBody; } }

### 3.2.3 PUT 方法 ###

1.  首先创建一个http请求 HttpPut httpPut = new HttpPut(url);
2.  自定义一个 Response Handler，向POST中添加数据（JSON 信息）和 Header信息
    
        httpPut.setHeader("Accept", "application/json"); httpPut.setHeader("Content-type", "application/json");
3.  执行 httpclient.execute(请求，Handler)
4.  处理返回

/** * put 方法 * @param url put 的 url * @param data 数据 application/json 的时候 为json格式 * @param heads Http Head 参数 * */ public static String put(String url,String data,Map<String,String> heads) throws IOException{ try (CloseableHttpClient httpclient = HttpClients.createDefault()) { HttpPut httpPut = new HttpPut(url); if(heads!=null){ Set<String> keySet=heads.keySet(); for(String s:keySet){ httpPut.addHeader(s,heads.get(s)); } } StringEntity stringEntity = new StringEntity(data); httpPut.setEntity(stringEntity); System.out.println("Executing request " + httpPut.getRequestLine()); // Create a custom response handler ResponseHandler < String > responseHandler = response -> { int status = response.getStatusLine().getStatusCode(); if (status >= 200 && status < 300) { HttpEntity entity = response.getEntity(); return entity != null ? EntityUtils.toString(entity) : null; } else { throw new ClientProtocolException("Unexpected response status: " + status); } }; String responseBody = httpclient.execute(httpPut, responseHandler); System.out.println("----------------------------------------"); System.out.println(responseBody); return responseBody; } }

### 3.2.4 DELETE 方法 ###

1.  首先创建一个http请求 HttpDelete httpDelete = new HttpDelete(url);
2.  自定义一个 Response Handler
3.  执行 httpclient.execute(请求，Handler)
4.  处理返回

/** * delete 方法 * @param url delete 的 url * @param heads Http Head 参数 * */ public static String delete(String url,Map<String,String> heads) throws IOException { try (CloseableHttpClient httpclient = HttpClients.createDefault()) { HttpDelete httpDelete = new HttpDelete(url); if(heads!=null){ Set<String> keySet=heads.keySet(); for(String s:keySet){ httpDelete.addHeader(s,heads.get(s)); } } System.out.println("Executing request " + httpDelete.getRequestLine()); // Create a custom response handler ResponseHandler < String > responseHandler = response -> { int status = response.getStatusLine().getStatusCode(); if (status >= 200 && status < 300) { HttpEntity entity = response.getEntity(); return entity != null ? EntityUtils.toString(entity) : null; } else { throw new ClientProtocolException("Unexpected response status: " + status); } }; String responseBody = httpclient.execute(httpDelete, responseHandler); System.out.println("----------------------------------------"); System.out.println(responseBody); return responseBody; } }

[本项目源码 github 下载][github]

--------------------

参考链接  
https://www.javaguides.net/2018/10/apache-httpclient-get-post-put-and-delete-methods-example.html

转载于:https://www.cnblogs.com/fishpro/p/spring-boot-study-httpclient.html

[github]: https://github.com/fishpro/spring-boot-study/tree/master/spring-boot-study-httpclient