java正则表达式应用

一：抓取网页中的Email地址

利用正则表达式匹配网页中的文本

[\\w[.-]]+@[\\w[.-]]+\\.[\\w]+

将网页内容分割提取

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


public class EmailSpider {

    public static void main(String[] args) {
        try {
            BufferedReader br = new BufferedReader(new FileReader("C:\\emailSpider.html"));
            String line = "";
            while((line=br.readLine()) != null) {
                parse(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void parse(String line) {
        Pattern p = Pattern.compile("[\\w[.-]]+@[\\w[.-]]+\\.[\\w]+");
        Matcher m = p.matcher(line);
        while(m.find()) {
            System.out.println(m.group());
        }
    }

}

打印结果：

867124664@qq.com
260678675@QQ.com
806208721@qq.com
hr_1985@163.com
32575987@qq.com
qingchen0501@126.com
yingyihanxin@foxmail.com
1170382650@qq.com
1170382650@qq.com
yingyihanxin@foxmail.com
qingchen0501@126.com
32575987@qq.com
hr_1985@163.com

现在你找到这么多邮箱地址，用上JavaMail的知识，你可以群发垃圾邮件了，呵呵！！！

二：代码统计

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

public class CodeCounter {
    
    static long normalLines = 0;//正常代码行
    static long commentLines = 0;//注释行
    static long whiteLines = 0;//空白行
    
    public static void main(String[] args) {
        //找到某个文件夹,该文件夹下面在没有文件夹，这里没有写递归处理不在同一文件夹的文件
        File f = new File("E:\\Workspaces\\eclipse\\Application\\JavaMailTest\\src\\com\\java\\mail");
        File[] codeFiles = f.listFiles();
        for(File child : codeFiles){
            //只统计java文件
            if(child.getName().matches(".*\\.java$")) {
                parse(child);
            }
        }
        
        System.out.println("normalLines:" + normalLines);
        System.out.println("commentLines:" + commentLines);
        System.out.println("whiteLines:" + whiteLines);
        
    }

    private static void parse(File f) {
        BufferedReader br = null;
        //表示是否为注释开始
        boolean comment = false;
        try {
            br = new BufferedReader(new FileReader(f));
            String line = "";
            while((line = br.readLine()) != null) {
                //去掉注释符/*前面可能出现的空白
                line = line.trim();
                //空行 因为readLine()将字符串取出来时，已经去掉了换行符\n
                //所以不是"^[\\s&&[^\\n]]*\\n$"
                if(line.matches("^[\\s&&[^\\n]]*$")) {
                    whiteLines ++;
                } else if (line.startsWith("/*") && !line.endsWith("*/")) {
                    //统计多行/*****/
                    commentLines ++;
                    comment = true;    
                } else if (line.startsWith("/*") && line.endsWith("*/")) {
                    //统计一行/**/
                    commentLines ++;
                } else if (true == comment) {
                    //统计*/
                    commentLines ++;
                    if(line.endsWith("*/")) {
                        comment = false;
                    }
                } else if (line.startsWith("//")) {
                    commentLines ++;
                } else {
                    normalLines ++;
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if(br != null) {
                try {
                    br.close();
                    br = null;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

}