网络爬虫简易代码

    import java.io.BufferedReader;  
    import java.io.FileWriter;  
    import java.io.IOException;  
    import java.io.InputStreamReader;  
    import java.io.PrintWriter;  
    import java.net.MalformedURLException;  
    import java.net.URL;  
    import java.net.URLConnection;  
    import java.util.regex.Matcher;  
    import java.util.regex.Pattern;  
      
    public class WebSpider {  
        public static void main(String[] args) {  
            URL url = null;  
            URLConnection urlconn = null;  
            BufferedReader br = null;  
            PrintWriter pw = null;  
            String regex = "http://[\\w+\\.?/?]+\\.[A-Za-z]+";  
            Pattern p = Pattern.compile(regex);  
            try {  
                url = new URL("http://www.sina.com.cn/");  
                urlconn = url.openConnection();  
                pw = new PrintWriter(new FileWriter("e:/url.txt"), true);//这里我们把收集到的链接存储在了E盘底下的一个叫做url的txt文件中  
                br = new BufferedReader(new InputStreamReader(  
                        urlconn.getInputStream()));  
                String buf = null;  
                while ((buf = br.readLine()) != null) {  
                    Matcher buf_m = p.matcher(buf);  
                    while (buf_m.find()) {