早就有想写一个Java Socket编程系列的文章，由于自己懒一直没动。决定从

今天开始，每周写一篇，从最简单的socket连接，到文件传输到协议实现，到

远程桌面控制，全面讲述Java socket编程的各个方面与各种技巧，从普通

socket到Java NIO。


本文算是第一篇，简述如何通过Java Socket获取网站的主页内容其中包括

如何获取本地机器名与IP地址，如何建立一个socket连接到远程WEB站点

如何使用HTTP GET方法获取网站主页内容与HTTP响应头。程序运行结果：


从中我们可以知道csdn网站是基于什么语言开发，服务器是什么，版本是多少。

具体的做法请看源代码：

package com.gloomyfish.socket.tutorial.one;  import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.net.InetAddress; import java.net.InetSocketAddress; import java.net.Socket; import java.net.SocketAddress; import java.net.UnknownHostException;  public class HomePageVisitor { 	private Socket client; 	private SocketAddress address; 	public HomePageVisitor(String hostName, int port) throws UnknownHostException, IOException { 		client = new Socket(); 		address = new InetSocketAddress(hostName, port); 	} 	// GET http://localhost:8080/blank/Welcome.do HTTP/1.1\r\n 	public void printHomePageInfo(String httpString) 	{ 		try { 			// Get local host info 	        InetAddress inetAddress = InetAddress.getLocalHost(); 	        System.out.println("Host Address = " + inetAddress.getHostAddress()); 	        System.out.println("Hostname = " + inetAddress.getHostName()); 	         	        // visit the WEBSITE 			client.connect(address); 			BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(client.getOutputStream(), "UTF8")); 			bufferedWriter.write(httpString); 			 			// -- HTTP/1.1 400 Bad Request if not send \r\n 			bufferedWriter.write("\r\n"); 			bufferedWriter.flush(); 			System.out.println("http request send out"); 			 			BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(client.getInputStream())); 			String content = null; 			while((content = bufferedReader.readLine()) != null) { 				if(getStatusCde(content) == 400) { 					System.err.println("HTTP/1.1 | HTTP/1.0 400 Bad Request"); 					break; 				} 				System.out.println("response contect -->> " + content); 			} 		} catch(Exception e) { 			e.printStackTrace(); 		} 		 	} 	 	/** 	 * 
 try to parse the HTTP response content
 	 * @param content 	 * @return status of HTTP 	 */ 	private static int getStatusCde(String content) { 		int status = 200; // default OK response 		if(content == null || "".equals(content)) 			return status; 		else if (!content.contains("HTTP/1.1")&& !content.contains("HTTP/1.0")) 			return status; 		else if(content.contains("400") && content.contains("HTTP/1.1") 				|| content.contains("HTTP/1.0")) { 			status = 400; 		} 		return status; 	} 	 	public static void main(String[] args) { 		try { 			HomePageVisitor httpVisitor = new HomePageVisitor("www.csdn.net", 80); 			httpVisitor.printHomePageInfo("GET http://www.csdn.net HTTP/1.0\r\n"); 		} catch (UnknownHostException e) { 			e.printStackTrace(); 		} catch (IOException e) { 			e.printStackTrace(); 		} 	} }
如果使用了代理，在初始化Address时候使用HTTP代理的地址与端口

接口，其它不变，代理会自动转发HTTP GET请求。代码如下：

address = new InetSocketAddress(http_proxy, proxy_port)