httpclient 详解——第一章；

httpclient 详解——第二章；

httpclient 详解——第三章；

httpclient 详解——第四章； 

httpclient 详解——第五章；

httpclient 详解——第六章；

相对于httpurlconnection ，httpclient更加丰富，也更加强大，其中apache有两个项目都是httpclient，一个是commonts包下的，这个是通用的，更专业的是org.apache.http.包下的，所以我一般用后者；

httpclient可以处理长连接，保存会话，重连接，以及请求过滤器，连接重用等等...

下面是测试代码（全部总结来自官方文档，以及翻译）

须要下载核心包：httpclient-4.3.4.jar ，也可在官网下载：http://hc.apache.org/downloads.cgi

/**
	 * 
	 */
	private static void test26() throws ClientProtocolException, IOException{
//		CloseableHttpClient httpclient = HttpClients.createDefault();  
//		HttpClientContext context = HttpClientContext.create();  
//		HttpGet httpget = new HttpGet("http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getDatabaseInfo");  
//		CloseableHttpResponse response = httpclient.execute(httpget, context);  
//		try {  
//		    Principal principal = context.getUserToken(Principal.class);  
//		    System.out.println(principal);  
//		} finally {  
//		    response.close();  
//		}
		
		
		
		CloseableHttpClient httpclient = HttpClients.createDefault();  
		HttpClientContext context1 = HttpClientContext.create();  
		HttpGet httpget1 = new HttpGet("http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getDatabaseInfo");  
		CloseableHttpResponse response1 = httpclient.execute(httpget1, context1);  
		try {  
		    HttpEntity entity1 = response1.getEntity();  
		} finally {
		    response1.close();  
		}  
		Principal principal = context1.getUserToken(Principal.class);  
		
		HttpClientContext context2 = HttpClientContext.create();  
		context2.setUserToken(principal);  
		HttpGet httpget2 = new HttpGet("http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getDatabaseInfo");  
		CloseableHttpResponse response2 = httpclient.execute(httpget2, context2);  
		try {  
		    HttpEntity entity2 = response2.getEntity();  
		} finally {  
		    response2.close();  
		}
		
		
	}
	
	

JAVA: httpclient 详解——第七章；