简单的网络爬虫程序（Web Crawlers）

程序比较简单，但是能体现基本原理。

package com.wxisme.webcrawlers;

import java.io.*;
import java.net.*;

/**
 * Web Crawlers * @author wxisme
 *
 */
public class WebCrawlers {

    public static void main(String[] args) {
        URL url = null;
        try {
            url = new URL("http://www.baidu.com");
        } catch (MalformedURLException e) {
            System.out.println("域名不合法！");
            e.printStackTrace();
        }
        InputStream is = null;
        try {
            is = url.openStream();
        } catch (IOException e) {
            e.printStackTrace();
        }

        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream("E:\\baidu.txt");
        } catch (FileNotFoundException e) {
            System.out.println("文件创建失败！");
            e.printStackTrace();
        }
        //使用转换流设置字符集
        BufferedReader br = null;
        try {
            br = new  BufferedReader(new InputStreamReader(
                    is,"utf-8"));
        } catch (UnsupportedEncodingException e) {
            System.out.println("字符集设置失败！");
            e.printStackTrace();
        }

        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
                fos));

        String msg = null;
        try {
            while((msg = br.readLine()) != null) {
                bw.write(msg);
                bw.newLine();
            }
        } catch (IOException e) {
            System.out.println("文件操作失败！");
            e.printStackTrace();
        } finally {
            try {
                bw.flush();
            } catch (IOException e) {
                e.printStackTrace();
            }
            closeAll(is, fos, br, bw);
        }

    }

    public static void closeAll(Closeable ... io) {
        for(Closeable temp : io) {
            if(temp != null) {
                try {
                    temp.close();
                } catch (IOException e) {
                    System.out.println("文件关闭失败!");
                    e.printStackTrace();
                }
            }
        }
    }

}