java爬虫

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.4399.com/");
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()) {
pw.println(buf_m.group());
}
}
System.out.println("获取成功！");
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
pw.close();
}
}
}

http://www.cnblogs.com/huangwentian/p/6484534.html