Java：正则表达式的详解

class RegexDemo
{
    public static void main(String[] args)
    {
        //CheckQQ_1();
        //CheckQQ();
        //demo();
        //CheckTel();
        //SplitDemo();
        ReplaceDemo();
    }

   //替换演示
   public static void ReplaceDemo()
   {
        //String str = "123dffhe568kkkdsr7885445e";//要求:将字符串的数字替换成‘#’
        //String regex = "\\d{5,}";//可以规定超过5个数字就将数字替换成‘#’
        //String s = "#";
        
        //String str = "zhakksxsqqwanwwwwu";//将叠词进行替换‘&‘
        //String regex = "(.)\\1+";
        //String s = "&";    

        String str = "zhakksxsqqwanwwwwu";//将叠词字符由多个变成一个
        String regex = "(.)\\1+";
        String s = "$1";            
        
        System.out.println(str.replaceAll(regex,s));
   }   
    
    //切割演示
    public static void SplitDemo()
    {
        //String  str = "zhangsan    lisi wangwu";
        //String regex = " +";     //一次或多次空格
        
        //String  str = "zhangsan.lisi.wangwu";
        //String regex = "\\.";    //特殊字符,对点和反斜杠进行转义
        
        //String  str = "zhangsan,lisi,wangwu";
        //String regex = ",";   

        //String  str = "c:\\zhangsan\\lisi\\wangwu";
        //String regex = "\\\\";


        String  str = "zhakksxsqqwanwwu";//按照叠词进行切割
        String regex = "(.)\\1+";//第一次切割的结果为组被重用,接着进行后面一次或多次的切割(每一个组按照顺序有编号,反向引用第一组)        
        
        String[] arr = str.split(regex);
        
        for(String s: arr)
        {
            System.out.println(s);
        }
    }
    //匹配字符演示
    public static void demo()
    {
        String str = "a";
        String regex = "[bcd]";//给定要比较的字符串中内容必须只能是规则中的某一个字符。
        boolean b = str.matches(regex);
        System.out.println(b);//false
    }
    

    
    //匹配手机号 13xxx，15xxx，18xxx
    public static void CheckTel()
    {
        String tel = "15000000000";
        String regex = "[1][358]\\d{9}";//"[1][358]\\d{3,10}"
        System.out.println(tel.matches(regex));
    }
    
    
    //匹配QQ号
    public static void CheckQQ()
    {
        String qq = "01237458";
        //String regex = "[1-9][0-9]{4,14}";
        String regex = "[1-9]\\d{4,14}";
        
        boolean flag = qq.matches(regex);
        
        if(flag)
            System.out.println("qq:"+qq);
        else
            System.out.println("qq不符合要求!");
    }
    

    
    
    /*
    需求：对QQ号码进行校验
    要求：5~15位，0不能开头，只能是数字
    这种方式是使用String类中的方法，进行组合完成了需求，但是代码过于复杂。
    */
    public static void CheckQQ_1()
    {
        String qq = "1237458";
        int len = qq.length();
        if(len>=5 && len<=15)
        {
            if(!qq.startsWith("0"))//qq.chatAt(0)==0  //Integer.parseInt("12a")  NumberFormatException
            {
                try
                {
                  long l = Long.parseLong(qq);
                  System.out.println("qq:"+qq);
                }
                catch(NumberFormatException e)
                {
                  System.out.println("qq出现非法字符......");    
                }
                
                /*
                char[] arr = qq.toCharArray();
                boolean flag = true;
                for(int i=0;i<arr.length;i++)
                {
                    if(!(arr[i]>=‘0‘ && arr[i]<=‘9‘))
                    {
                        flag = false;
                        break;                    
                    }
                }
                if(flag)
                {
                    System.out.println("qq:"+qq);
                }
                else
                {
                    System.out.println("qq出现非法字符!");
                }
                */
            }
            else
            {
                System.out.println("qq不能以0开头!");
            }
        }
        else
        {
            System.out.println("qq号长度错误,请重新输入!");
        }
    }    
}