java发送http请求的两种方式：HTTPClient和CloseableHttpClient

た入场券 2022-05-09 01:52 308阅读 0赞

# java发送http请求的两种方式：HTTPClient和CloseableHttpClient #

下面分别介绍使用HTTPClient和CloseableHTTPClient进行Get和Post请求的方式。

## HttpClient ##

使用commons-httpclient.jar，maven依赖如下：

<dependency>
          <groupId>commons-httpclient</groupId>
          <artifactId>commons-httpclient</artifactId>
          <version>3.1</version>
        </dependency>

java示例代码如下：

package com.example.study.demo.http;
    
    import org.apache.commons.httpclient.HttpClient;
    import org.apache.commons.httpclient.methods.GetMethod;
    import org.apache.commons.httpclient.methods.PostMethod;
    
    import java.io.IOException;
    
    /** * HttpClient使用示例 * jar包：commons-httpclient.jar */
    public class HttpClientTest { 
      private static void doGet() { 
        HttpClient client = new HttpClient();
        GetMethod getMethod = new GetMethod("https://www.thepaper.cn/");
        int code = 0;
        try { 
          code = client.executeMethod(getMethod);
          if (code == 200) { 
            String res = getMethod.getResponseBodyAsString();
            System.out.println(res);
          }
        } catch (IOException e) { 
          e.printStackTrace();
        }
      }
    
      private static void doPost() { 
        String praiseUrl = "https://www.thepaper.cn/www/commentPraise.msp"; // 澎湃新闻评论点赞url
        HttpClient client = new HttpClient();
        PostMethod postMethod = new PostMethod(praiseUrl);
        // 必须设置下面这个Header
        postMethod.addRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
        postMethod.addParameter("commentId", "18718372"); // 评论的id，抓包获得
        try { 
          int code = client.executeMethod(postMethod);
          if (code == 200) { 
            String res = postMethod.getResponseBodyAsString();
            System.out.println(res);
          }
        } catch (IOException e) { 
          e.printStackTrace();
        }
      }
    
      public static void main(String[] args) { 
        doGet();
        System.out.println("-----------分割线------------");
        System.out.println("-----------分割线------------");
        System.out.println("-----------分割线------------");
        doPost();
      }
    }

## CloseableHttpClient ##

使用httpclient.jar，maven依赖如下：

<dependency>
          <groupId>org.apache.httpcomponents</groupId>
          <artifactId>httpclient</artifactId>
          <version>4.5.2</version>
        </dependency>

java示例代码如下：

package com.example.study.demo.http;
    
    import org.apache.http.HttpResponse;
    import org.apache.http.NameValuePair;
    import org.apache.http.client.ClientProtocolException;
    import org.apache.http.client.entity.UrlEncodedFormEntity;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClientBuilder;
    import org.apache.http.message.BasicNameValuePair;
    import org.apache.http.protocol.HTTP;
    import org.apache.http.util.EntityUtils;
    
    import java.io.IOException;
    import java.io.UnsupportedEncodingException;
    import java.util.ArrayList;
    import java.util.List;
    
    /** * CloseableHttpClient使用示例 * jar包：httpclient.jar */
    public class CloseableHttpClientTest { 
    
      public static void doGet() { 
        CloseableHttpClient client = HttpClientBuilder.create().build();
        HttpGet get = new HttpGet("http://www.thepaper.cn");
        try { 
          // 很奇怪，使用CloseableHttpClient来请求澎湃新闻的首页，GTE请求也必须加上下面这个Header，但是使用HTTPClient则不需要
          get.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
          HttpResponse response = client.execute(get);
          String res = EntityUtils.toString(response.getEntity());
          System.out.println(res);
        } catch (IOException e) { 
          e.printStackTrace();
        }
      }
    
      public static void doPost() { 
        CloseableHttpClient client = HttpClientBuilder.create().build();
        HttpPost post = new HttpPost("https://www.thepaper.cn/www/commentPraise.msp");
        try { 
          post.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
          List<NameValuePair> params = new ArrayList<>();
          params.add(new BasicNameValuePair("commentId", "18718372"));
          post.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
          HttpResponse response = client.execute(post);
          String res = EntityUtils.toString(response.getEntity());
          System.out.println(res);
        } catch (UnsupportedEncodingException e) { 
          e.printStackTrace();
        } catch (ClientProtocolException e) { 
          e.printStackTrace();
        } catch (IOException e) { 
          e.printStackTrace();
        }
      }
    
    
      public static void main(String[] args) { 
        doGet();
        System.out.println("-----------分割线------------");
        System.out.println("-----------分割线------------");
        System.out.println("-----------分割线------------");
        doPost();
    
      }
    }

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