JAVAがHttpClientを通じてHTTP要求を送信する方法の例

Http Clientの紹介
HttpClientはブラウザではありません。クライアントのHTTP通信実現ライブラリです。HttpClientの目標はHTTPメッセージの送信と受信です。HttpClientは内容をキャッシュしないで、HTMLページに埋め込まれたjavascriptコードを実行して、内容のタイプを推測して、改めて要求/リダイレクトURIをフォーマットして、あるいは他のHTTP運送と関係がない機能です。
Http Client使用
使用するにはjarパッケージを導入する必要があります。Mavenプロジェクトは以下の通り導入されます。

<dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5</version>
    </dependency>

    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpcore</artifactId>
      <version>4.4.4</version>
    </dependency>

    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpmime</artifactId>
      <version>4.5</version>
    </dependency>

使用方法、コードは以下の通りです。

package com.test;

import java.io.File;
import java.io.IOException;
import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.http.HttpEntity;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLContextBuilder;
import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.util.EntityUtils;

/**
 * 
 * @author H__D
 * @date 2016 10 19    11:27:25
 *
 */
public class HttpClientUtil {

  // utf-8    
  public static final String CHARSET_UTF_8 = "utf-8";

  // HTTP    。
  public static final String CONTENT_TYPE_TEXT_HTML = "text/xml";

  // HTTP    。   form     ，    
  public static final String CONTENT_TYPE_FORM_URL = "application/x-www-form-urlencoded";

  // HTTP    。   form     ，    
  public static final String CONTENT_TYPE_JSON_URL = "application/json;charset=utf-8";
  

  //      
  private static PoolingHttpClientConnectionManager pool;

  //     
  private static RequestConfig requestConfig;

  static {
    
    try {
      //System.out.println("   HttpClientTest~~~  ");
      SSLContextBuilder builder = new SSLContextBuilder();
      builder.loadTrustMaterial(null, new TrustSelfSignedStrategy());
      SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
          builder.build());
      //        HTTP   HTPPS
      Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory> create().register(
          "http", PlainConnectionSocketFactory.getSocketFactory()).register(
          "https", sslsf).build();
      //         
      pool = new PoolingHttpClientConnectionManager(
          socketFactoryRegistry);
      //          200，                 
      pool.setMaxTotal(200);
      //       
      pool.setDefaultMaxPerRoute(2);
      //            requestConfig
      int socketTimeout = 10000;
      int connectTimeout = 10000;
      int connectionRequestTimeout = 10000;
      requestConfig = RequestConfig.custom().setConnectionRequestTimeout(
          connectionRequestTimeout).setSocketTimeout(socketTimeout).setConnectTimeout(
          connectTimeout).build();

      //System.out.println("   HttpClientTest~~~  ");
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    } catch (KeyStoreException e) {
      e.printStackTrace();
    } catch (KeyManagementException e) {
      e.printStackTrace();
    }
    

    //         
    requestConfig = RequestConfig.custom().setSocketTimeout(50000).setConnectTimeout(50000)
        .setConnectionRequestTimeout(50000).build();
  }

  public static CloseableHttpClient getHttpClient() {
    
    CloseableHttpClient httpClient = HttpClients.custom()
        //        
        .setConnectionManager(pool)
        //       
        .setDefaultRequestConfig(requestConfig)
        //       
        .setRetryHandler(new DefaultHttpRequestRetryHandler(0, false))
        .build();
    
    return httpClient;
  }

  /**
   *   Post  
   * 
   * @param httpPost
   * @return
   */
  private static String sendHttpPost(HttpPost httpPost) {

    CloseableHttpClient httpClient = null;
    CloseableHttpResponse response = null;
    //     
    String responseContent = null;
    try {
      //      httpClient  .
      httpClient = getHttpClient();
      //       
      httpPost.setConfig(requestConfig);
      //     
      response = httpClient.execute(httpPost);
      //       
      HttpEntity entity = response.getEntity();

      //        
      // Header[] headers = response.getHeaders(HttpHeaders.CONTENT_TYPE);
      // for (Header header : headers) {
      // System.out.println(header.getName());
      // }

      //       
      // System.out.println(ContentType.getOrDefault(response.getEntity()).getMimeType());

      //       
      if (response.getStatusLine().getStatusCode() >= 300) {
        throw new Exception(
            "HTTP Request is not success, Response code is " + response.getStatusLine().getStatusCode());
      }

      if (HttpStatus.SC_OK == response.getStatusLine().getStatusCode()) {
        responseContent = EntityUtils.toString(entity, CHARSET_UTF_8);
        EntityUtils.consume(entity);
      }

    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      try {
        //     
        if (response != null) {
          response.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    return responseContent;
  }

  /**
   *   Get  
   * 
   * @param httpGet
   * @return
   */
  private static String sendHttpGet(HttpGet httpGet) {

    CloseableHttpClient httpClient = null;
    CloseableHttpResponse response = null;
    //     
    String responseContent = null;
    try {
      //      httpClient  .
      httpClient = getHttpClient();
      //       
      httpGet.setConfig(requestConfig);
      //     
      response = httpClient.execute(httpGet);
      //       
      HttpEntity entity = response.getEntity();

      //        
      // Header[] headers = response.getHeaders(HttpHeaders.CONTENT_TYPE);
      // for (Header header : headers) {
      // System.out.println(header.getName());
      // }

      //       
      // System.out.println(ContentType.getOrDefault(response.getEntity()).getMimeType());

      //       
      if (response.getStatusLine().getStatusCode() >= 300) {
        throw new Exception(
            "HTTP Request is not success, Response code is " + response.getStatusLine().getStatusCode());
      }

      if (HttpStatus.SC_OK == response.getStatusLine().getStatusCode()) {
        responseContent = EntityUtils.toString(entity, CHARSET_UTF_8);
        EntityUtils.consume(entity);
      }

    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      try {
        //     
        if (response != null) {
          response.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    return responseContent;
  }
  
  
  
  /**
   *    post  
   * 
   * @param httpUrl
   *        
   */
  public static String sendHttpPost(String httpUrl) {
    //   httpPost
    HttpPost httpPost = new HttpPost(httpUrl);
    return sendHttpPost(httpPost);
  }

  /**
   *    get  
   * 
   * @param httpUrl
   */
  public static String sendHttpGet(String httpUrl) {
    //   get  
    HttpGet httpGet = new HttpGet(httpUrl);
    return sendHttpGet(httpGet);
  }
  
  

  /**
   *    post  （   ）
   * 
   * @param httpUrl
   *        
   * @param maps
   *        
   * @param fileLists
   *        
   */
  public static String sendHttpPost(String httpUrl, Map<String, String> maps, List<File> fileLists) {
    HttpPost httpPost = new HttpPost(httpUrl);//   httpPost
    MultipartEntityBuilder meBuilder = MultipartEntityBuilder.create();
    if (maps != null) {
      for (String key : maps.keySet()) {
        meBuilder.addPart(key, new StringBody(maps.get(key), ContentType.TEXT_PLAIN));
      }
    }
    if (fileLists != null) {
      for (File file : fileLists) {
        FileBody fileBody = new FileBody(file);
        meBuilder.addPart("files", fileBody);
      }
    }
    HttpEntity reqEntity = meBuilder.build();
    httpPost.setEntity(reqEntity);
    return sendHttpPost(httpPost);
  }

  /**
   *    post  
   * 
   * @param httpUrl
   *        
   * @param params
   *        (  :key1=value1&key2=value2)
   * 
   */
  public static String sendHttpPost(String httpUrl, String params) {
    HttpPost httpPost = new HttpPost(httpUrl);//   httpPost
    try {
      //     
      if (params != null && params.trim().length() > 0) {
        StringEntity stringEntity = new StringEntity(params, "UTF-8");
        stringEntity.setContentType(CONTENT_TYPE_FORM_URL);
        httpPost.setEntity(stringEntity);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    return sendHttpPost(httpPost);
  }

  /**
   *    post  
   * 
   * @param maps
   *        
   */
  public static String sendHttpPost(String httpUrl, Map<String, String> maps) {
    String parem = convertStringParamter(maps);
    return sendHttpPost(httpUrl, parem);
  }

  
  
  
  /**
   *    post     json  
   * 
   * @param httpUrl
   *        
   * @param paramsJson
   *        (   json)
   * 
   */
  public static String sendHttpPostJson(String httpUrl, String paramsJson) {
    HttpPost httpPost = new HttpPost(httpUrl);//   httpPost
    try {
      //     
      if (paramsJson != null && paramsJson.trim().length() > 0) {
        StringEntity stringEntity = new StringEntity(paramsJson, "UTF-8");
        stringEntity.setContentType(CONTENT_TYPE_JSON_URL);
        httpPost.setEntity(stringEntity);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    return sendHttpPost(httpPost);
  }
  
  /**
   *    post     xml  
   * 
   * @param httpUrl    
   * @param paramsXml   (   Xml)
   * 
   */
  public static String sendHttpPostXml(String httpUrl, String paramsXml) {
    HttpPost httpPost = new HttpPost(httpUrl);//   httpPost
    try {
      //     
      if (paramsXml != null && paramsXml.trim().length() > 0) {
        StringEntity stringEntity = new StringEntity(paramsXml, "UTF-8");
        stringEntity.setContentType(CONTENT_TYPE_TEXT_HTML);
        httpPost.setEntity(stringEntity);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    return sendHttpPost(httpPost);
  }
  

  /**
   *  map         ：key1=value1&key2=value2    
   * 
   * @param parameterMap
   *                
   * @return    
   */
  public static String convertStringParamter(Map parameterMap) {
    StringBuffer parameterBuffer = new StringBuffer();
    if (parameterMap != null) {
      Iterator iterator = parameterMap.keySet().iterator();
      String key = null;
      String value = null;
      while (iterator.hasNext()) {
        key = (String) iterator.next();
        if (parameterMap.get(key) != null) {
          value = (String) parameterMap.get(key);
        } else {
          value = "";
        }
        parameterBuffer.append(key).append("=").append(value);
        if (iterator.hasNext()) {
          parameterBuffer.append("&");
        }
      }
    }
    return parameterBuffer.toString();
  }

  public static void main(String[] args) throws Exception {
    
    System.out.println(sendHttpGet("http://www.baidu.com"));
  
  }
}

以上が本文の全部です。皆さんの勉強に役に立つように、私たちを応援してください。