java 正则表达式 爬贴吧帖子邮箱

package Main;import java.io.BufferedReader;import java.io.InputStreamReader;import java.net.URL;import java.util.TreeSet;import java.util.regex.Matcher;import java.util.regex.Pattern;public class Main {    public static void main(String[] args)  throws Exception {        String mail_regex="\\w+@\\w+(\\.\\w+)+";        TreeSet<String> list=new TreeSet<String>();        Pattern p=Pattern.compile(mail_regex);        String line=null;        URL url=new URL("https://tieba.baidu.com/p/5314758062?pn=1");        BufferedReader buf=new BufferedReader(new InputStreamReader(url.openStream()));        while((line=buf.readLine())!=null) {            Matcher m = p.matcher(line);            while(m.find())                list.add(m.group());        }        URL url2=new URL("https://tieba.baidu.com/p/5314758062?pn=2");        BufferedReader buf2=new BufferedReader(new InputStreamReader(url2.openStream()));        while((line=buf2.readLine())!=null) {            Matcher m = p.matcher(line);            while(m.find())                list.add(m.group());        }        for (String s:list             ) {            System.out.println(s);        }    }}