Java实现网络爬虫入门Demo

需求：

抓取一个网页（比如www.lianhehuishang）中的url地址，并存到F:\spider_url.txt文件中。

程序：

package com.zheng;


import java.io.BufferedReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.MalformedURLException;
import java.URL;
import java.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 = Patternpile(regex);
		try {
			url = new URL("http://www.lianhehuishang/");
			urlconn = url.openConnection();
			pw = new PrintWriter(new FileWriter("f:\\spider_url.txt"), true);
			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();
		}
	}
}

运行结果：

                                         

打开F:\spider_url.txt