httpClient例子詳解

阿新 • • 發佈：2019-01-21

package com.xf.httpclient;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.InterruptedIOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.UnknownHostException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import javax.net.ssl.SSLException;

import org.apache.http.Consts;
import org.apache.http.HeaderElement;
import org.apache.http.HeaderElementIterator;
import org.apache.http.HttpClientConnection;
import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpException;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpRequestInterceptor;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpRequestRetryHandler;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
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.client.protocol.HttpClientContext;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.client.utils.URIUtils;
import org.apache.http.conn.ConnectTimeoutException;
import org.apache.http.conn.ConnectionKeepAliveStrategy;
import org.apache.http.conn.ConnectionRequest;
import org.apache.http.conn.HttpClientConnectionManager;
import org.apache.http.conn.routing.HttpRoute;
import org.apache.http.entity.ContentType;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.DefaultConnectionKeepAliveStrategy;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.client.LaxRedirectStrategy;
import org.apache.http.impl.conn.BasicHttpClientConnectionManager;
import org.apache.http.message.BasicHeaderElementIterator;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.EntityUtils;

public class HttpClientDeno {

  
  public static void main(String[] args) {
    
    try {
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
  
  
  
  
  
  
  /**
   * 測試1： 構建複雜uri，這種方式會很方便的設定多個引數；
   * 
   * HttpClients類是client的具體一個實現類；
   * 
   * URIBuilder包含：協議，主機名，埠（可選），資源路徑，和多個引數（可選）
   * 
   */
  private static void test1() {
    
    CloseableHttpClient client = HttpClients.createDefault();
    
    URI uri = null;
    try {
      uri = new URIBuilder()
      .setScheme("http")
      .setHost("webservice.webxml.com.cn")
      .setPath("/WebServices/MobileCodeWS.asmx/getDatabaseInfo")
      .setParameter("", "")//這裡可以設定多個引數
      .setParameter("", "")
      .setParameter("", "")
      .setParameter("", "")
      .build();
    } catch (URISyntaxException e1) {
      e1.printStackTrace();
    }
    
    //http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getDatabaseInfo
    HttpGet get = new HttpGet(uri);
    try {
      CloseableHttpResponse response = client.execute(get);
      
      if(response.getStatusLine().getStatusCode()==200){
        
        
        System.out.println(EntityUtils.toString(response.getEntity()));
        
        //以下這種方式讀取流也可以，只不過用EntityUtils會更方便
        /*InputStream is = response.getEntity().getContent();
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len=-1;
        while((len = is.read(buffer))!=-1){
          os.write(buffer,0,len);
        }
        os.close();
        is.close();
        System.out.println(os.size()+new String(os.toByteArray(),"utf-8"));*/
      }
    } catch (ClientProtocolException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
  
  
  /**
   * 為uri進行加密，並進行表單提交；
   * 
   * 許多應用需要模擬提交的HTML表單的處理，例如，在
    為了登入到Web應用程式或提交的輸入資料。 HttpClient提供的實體類
    UrlEncodedFormEntity可以實現該過程；
   */
  private static void test2(){
    
    CloseableHttpClient client = HttpClients.createDefault();
    
    HttpPost httppost = new HttpPost("http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getMobileCodeInfo");
    
    //構建請求引數
    List<NameValuePair> list = new ArrayList<NameValuePair>();
    list.add(new BasicNameValuePair("mobileCode", "110"));
    list.add(new BasicNameValuePair("userID", ""));

    //構建url加密實體，並以utf-8方式進行加密；
    UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list, Consts.UTF_8);
    httppost.setEntity(entity);
    
    try {
      CloseableHttpResponse response = client.execute(httppost);
      
      if(response.getStatusLine().getStatusCode()==200){
        
        //org.apache.http.util.EntityUtils類可以快速處理伺服器返回實體物件
        System.out.println(EntityUtils.toString(response.getEntity()));
        
      }
    } catch (ClientProtocolException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  
  }
  
  
  /**
   * 以回撥方式處理返回結果
   * 
   *  處理響應的最簡單和最方便的方法是通過使用ResponseHandler的
    介面。使用者不必擔心連線管理的問題。當使用一個
    ResponseHandler的時候，無論是否請求執行成功或導致異常，HttpClient將會自動釋放連線。
   */
  private static void test3(){
    
    CloseableHttpClient client = HttpClients.createDefault();
    
    //==============================================================
    ResponseHandler<Object> handler = new ResponseHandler<Object>() {
      @Override
      public Object handleResponse(final HttpResponse response) throws IOException {
        
        HttpEntity entity = response.getEntity();
        
        if (entity == null) {
          throw new ClientProtocolException("返回結果為空");
        }
      
        if(response.getStatusLine().getStatusCode()==200){
          
          //獲取返回結果的字符集 如：utf-8  gbk，並以這種字符集來讀取流資訊
          ContentType contentType = ContentType.getOrDefault(entity);
          Charset charset = contentType.getCharset();
          
          InputStreamReader reader = new InputStreamReader(entity.getContent(), charset);
          BufferedReader br = new BufferedReader(reader);
          StringBuffer sb = new StringBuffer();
          char[] buffer = new char[1024];
          while (br.read(buffer)!=-1) {
            sb.append(new String(buffer));
          }
          
          return sb.toString();
        }
        
        return null;
        
      }
    };
    //===================================================================
    
    URI uri = null;//構建uri實體
    try {
      uri = new URIBuilder()
      .setScheme("http")
      .setHost("webservice.webxml.com.cn")
      .setPath("/WebServices/MobileCodeWS.asmx/getDatabaseInfo")
      .setParameter("", "")
      .setParameter("", "")
      .setParameter("", "")
      .build();
      
    } catch (URISyntaxException e) {
      e.printStackTrace();
    }
    
    HttpPost post = new HttpPost(uri);
    
    try {
      
      //handler回撥
       Object obj = client.execute(post, handler);
       
       System.out.println("返回結果："+obj);
      
    } catch (ClientProtocolException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
    
  }
  
  
  
  /**
   * 	設定長連線策略，根據伺服器的約束或者客戶端的約束來設定長連線的時長；
   */
  private static void test4() {
    
	  ConnectionKeepAliveStrategy strategy = new DefaultConnectionKeepAliveStrategy() {
      
	      /**
	       * 伺服器端配置（以tomcat為例）：keepAliveTimeout=60000，表示在60s內內，伺服器會一直保持連線狀態。
	       * 也就是說，如果客戶端一直請求伺服器，且間隔未超過60s，則該連線將一直保持，如果60s內未請求，則超時。
	       * 
	       * getKeepAliveDuration返回超時時間；
	       */
	      @Override
	      public long getKeepAliveDuration(HttpResponse response, HttpContext context) {
	    	  	//如果伺服器指定了超時時間，則以伺服器的超時時間為準
		        HeaderElementIterator it = new BasicHeaderElementIterator(response.headerIterator(HTTP.CONN_KEEP_ALIVE));
		        while (it.hasNext()) {
		          HeaderElement he = it.nextElement();
		          String param = he.getName();
		          String value = he.getValue();
		          if (value != null && param.equalsIgnoreCase("timeout")) {
		            try {
		              System.out.println("伺服器指定的超時時間：" + value + " 秒");
		              return Long.parseLong(value) * 1000;
		            } catch (NumberFormatException ignore) {
		              ignore.printStackTrace();
		            }
		          }
		        }
	            
	            long keepAlive = super.getKeepAliveDuration(response, context);
	        
	            // 如果伺服器未指定超時時間，則客戶端預設30s超時
		        if (keepAlive == -1) {
		          keepAlive = 30 * 1000;
		        }
		            
		        return keepAlive;
	            
	            /*如果訪問webservice.webxml.com.cn主機，則超時時間5秒，其他主機超時時間30秒
	            HttpHost host = (HttpHost) context.getAttribute(HttpClientContext.HTTP_TARGET_HOST);
	            if ("webservice.webxml.com.cn".equalsIgnoreCase(host.getHostName())) {
	            	keepAlive =  10 * 1000;
	            } else {
	            	keepAlive =  30 * 1000;
	            }*/
	            
	            
	      	}
		};
    
	    CloseableHttpClient client = HttpClients.custom().setKeepAliveStrategy(strategy).build();
	    
	    URI uri = null;//構建uri實體
	    try {
	      uri = new URIBuilder()
	      .setScheme("http")
	      .setHost("webservice.webxml.com.cn")
	      .setPath("/WebServices/MobileCodeWS.asmx/getDatabaseInfo")
	      .setParameter("", "")
	      .build();
	      
	    } catch (URISyntaxException e) {
	      e.printStackTrace();
	    }
	    
	    HttpPost post = new HttpPost(uri);
	    
	    try {
	      CloseableHttpResponse response =  client.execute(post);
	      if(response.getStatusLine().getStatusCode()==200){
		     String result = EntityUtils.toString(response.getEntity());
		     System.out.println("返回的結果====="+result);
	      }
	      
	    } catch (ClientProtocolException e) {
	      e.printStackTrace();
	    } catch (IOException e) {
	      e.printStackTrace();
	    }
    
  }
  
  
  /**
   * 構建複雜請求體
   * 
   * RequestConfig將會儲存在context上下文中，並會在連續的請求中進行傳播（來自官方文件）；
   * 
   */
  private void test5(){

    CloseableHttpClient client = HttpClients.createDefault();
    
    //構建請求配置
    RequestConfig config = RequestConfig.
        custom().
        setSocketTimeout(1000*10).
        setConnectTimeout(1000*10).
        build();
    //==============================================================
    ResponseHandler<Object> handler = new ResponseHandler<Object>() {//回撥
      @Override
      public Object handleResponse(final HttpResponse response) throws IOException {
        
        HttpEntity entity = response.getEntity();
        
        if (entity == null) {
          throw new ClientProtocolException( "返回結果為空");
        }
      
        if(response.getStatusLine().getStatusCode()==200){
          ContentType contentType = ContentType.getOrDefault(entity);
          Charset charset = contentType.getCharset();
          
          InputStreamReader reader = new InputStreamReader(entity.getContent(), charset);
          BufferedReader br = new BufferedReader(reader);
          StringBuffer sb = new StringBuffer();
          char[] buffer = new char[1024];
          while (br.read(buffer)!=-1) {
            sb.append(new String(buffer));
          }
          
          return sb.toString();
        }
        
        return null;
        
      }
    };
    //===================================================================
    
    URI uri = null;
    try {
      uri = new URIBuilder()
      .setScheme("http")
      .setHost("webservice.webxml.com.cn")
      .setPath("/WebServices/MobileCodeWS.asmx/getDatabaseInfo")
      .setParameter("", "")
      .setParameter("", "")
      .setParameter("", "")
      .build();
      
    } catch (URISyntaxException e) {
      e.printStackTrace();
    }
    
    HttpPost post = new HttpPost(uri);
    
    post.setConfig(config);//設定請求配置
    
    try {
       Object obj = client.execute(post, handler);
       
       System.out.println("返回結果："+obj);
      
    } catch (ClientProtocolException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
    
  
  }
  
  
  
  /**
   *  異常恢復機制：
   *  
   *  HttpRequestRetryHandler連線失敗後，可以針對相應的異常進行相應的處理措施；
   *  HttpRequestRetryHandler介面須要使用者自己實現；
   *  
   */
  private static  void test6(){

    HttpRequestRetryHandler retryHandler = new HttpRequestRetryHandler() {
      
      /**
       * exception異常資訊；
       * executionCount：重連次數；
       * context：上下文
       */
      @Override
      public boolean retryRequest(IOException exception, int executionCount,HttpContext context) {

        System.out.println("重連線次數："+executionCount);
        
        if (executionCount >= 5) {//如果連線次數超過5次，就不進行重複連線
          return false;
        }
        if (exception instanceof InterruptedIOException) {//io操作中斷
          return false;
        }
        if (exception instanceof UnknownHostException) {//未找到主機
          // Unknown host
          return false;
        }
        if (exception instanceof ConnectTimeoutException) {//連線超時
          return true;
        }
        if (exception instanceof SSLException) {
          // SSL handshake exception
          return false;
        }
        HttpClientContext clientContext = HttpClientContext.adapt(context);
        
        HttpRequest request = clientContext.getRequest();
        
        boolean idempotent = !(request instanceof HttpEntityEnclosingRequest);
        
        if (idempotent) {
          // Retry if the request is considered idempotent
          return true;
        }
        return false;
      }
    };
    
    
    CloseableHttpClient client = HttpClients.custom().setRetryHandler(retryHandler).build();
    
    RequestConfig config = RequestConfig.
        custom().
        setSocketTimeout(1000*10).
        setConnectTimeout(1000*10).
        build();
    
    HttpPost post = new HttpPost("http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getDatabaseInfo");
    
    post.setConfig(config);
    
    try {
      HttpResponse response = client.execute(post);
      HttpEntity entity = response.getEntity();
      
      ContentType contentType = ContentType.getOrDefault(entity);
      Charset charset = contentType.getCharset();

      InputStreamReader reader = new InputStreamReader(entity.getContent(), charset);
      BufferedReader br = new BufferedReader(reader);
      StringBuffer sb = new StringBuffer();
      char[] buffer = new char[1024];
      while (br.read(buffer) != -1) {
        sb.append(new String(buffer));
      }

      System.out.println("返回的結果："+sb.toString());

    } catch (ClientProtocolException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
    
  }
  
  
  /**
   * 	HTTP請求過濾器，在執行請求之前攔截HttpRequest 和 HttpContext；
   */
  private static void test7() throws ClientProtocolException, IOException{
    
    HttpRequestInterceptor requestInterceptor = new HttpRequestInterceptor() {
      /**
       * 處理請求：
       * 如果是客戶端：這個處理在傳送請求之前執行；
       * 如果是伺服器：這個處理在接收到請求體之前執行；
       */
      public void process(final HttpRequest request, final HttpContext context) throws HttpException, IOException {
        AtomicInteger count = (AtomicInteger) context.getAttribute("count");
        request.addHeader("count", Integer.toString(count.getAndIncrement()));
      }
    };
    
    
    CloseableHttpClient httpclient = HttpClients.
            custom().
            addInterceptorLast(requestInterceptor).
            build();
    
    
    AtomicInteger count = new AtomicInteger(1);
    HttpClientContext context = HttpClientContext.create();
    context.setAttribute("count", count);
    HttpGet httpget = new HttpGet("http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getDatabaseInfo");
    
    for (int i = 0; i < 10; i++) {
      CloseableHttpResponse response = httpclient.execute(httpget,context);
      try {
        
        HttpEntity entity = response.getEntity();
//				System.out.println(EntityUtils.toString(entity));
        
      } finally {
        response.close();
      }
    }
  }
  
  /**
   * 
   *  	httpclient會自動處理重定向; 
   *  
   * 	301 永久重定向,告訴客戶端以後應從新地址訪問.
    	302 作為HTTP1.0的標準,以前叫做Moved Temporarily ,現在叫Found. 現在使用只是為了相容性的  處理,包括PHP的預設Location重定向用的也是302.
    	但是HTTP 1.1 有303 和307作為詳細的補充,其實是對302的細化
    	303：對於POST請求，它表示請求已經被處理，客戶端可以接著使用GET方法去請求Location裡的URI。
    	307：對於POST請求，表示請求還沒有被處理，客戶端應該向Location裡的URI重新發起POST請求。
   */
  private static void test8() throws ClientProtocolException, IOException,URISyntaxException {
	    LaxRedirectStrategy redirectStrategy = new LaxRedirectStrategy();
	    CloseableHttpClient httpclient = HttpClients.custom().setRedirectStrategy(redirectStrategy).build();
	
	    HttpClientContext context = HttpClientContext.create();
	    HttpGet httpget = new HttpGet("http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getDatabaseInfo");
	    CloseableHttpResponse response = httpclient.execute(httpget, context);
	    try {
		  HttpHost target = context.getTargetHost();
		  List<URI> redirectLocations = context.getRedirectLocations();
		  URI location = URIUtils.resolve(httpget.getURI(), target, redirectLocations);
		  System.out.println("Final HTTP location: " + location.toASCIIString());
	    } finally {
	      response.close();
	    }
  }
  
  
}

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