java正则表达式判断邮件地址是否合法

import java.util.regex.Matcher;  import java.util.regex.Pattern;  import java.util.Scanner;     public class Email{      public static void main(String []args){          Scanner scan = new Scanner(System.in);          String str=null;          str = scan.next();          String pat="[a-zA-Z0-9_\\-\\.]+@[a-zA-Z0-9]+(\\.(com))";          Pattern p = Pattern.compile(pat);//实例化Pattern类          Matcher m = p.matcher(str);//验证内容是否合法          if(m.matches())            System.out.println("YES");          else            System.out.println("NO");      }  }