Java Socket编程 - 获取WEB站点主页信息

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：

[java]
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();
        }

    }

    /**
     * <p> try to parse the HTTP response content</p>
     * @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：

[java]
address = new InetSocketAddress(http_proxy, proxy_port)

补充：软件开发 , Java ,