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Java determines whether ip

Release: 2019-11-20 13:47:36
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Java determines whether ip

java使用正则表达式判断是否是IP:

package com.you.dao;  
  
import java.util.regex.Matcher;  
import java.util.regex.Pattern;  
  
/** 
 * @类名:IpAddress 
 * @描述:用正则表达式判断是否为IP 
 */  
public class IpAddress   
{  
    public static class IpAdd  
    {  
        public boolean isIP(String addr)  
        {  
            if(addr.length() < 7 || addr.length() > 15 || "".equals(addr))  
            {  
                return false;  
            }  
            /** 
             * 判断IP格式和范围 
             */  
            String rexp = "([1-9]|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3}";  
              
            Pattern pat = Pattern.compile(rexp);    
              
            Matcher mat = pat.matcher(addr);    
              
            boolean ipAddress = mat.find();  
  
            return ipAddress;  
        }  
    }  
  
    /** 
     * @Title : main 
     * @Type : IpAddress 
     * @date : 2014年3月4日 下午10:55:06 
     * @Description : IP可能的范围是0-255.0-255.0-255.0-255 
     * @param args 
     */  
    public static void main(String[] args)   
    {  
        /** 
         * 符合IP地址的范围 
         */  
         String oneAddress = "10.127.30.45";  
         /** 
         * 符合IP地址的长度范围但是不符合格式 
         */  
         String twoAddress = "127.30.45";  
         /** 
         * 不符合IP地址的长度范围 
         */  
         String threeAddress = "7.0.4";  
         /** 
         * 不符合IP地址的长度范围但是不符合IP取值范围 
         */  
         String fourAddress = "255.255.255.2567";  
           
         IpAdd ipAdd = new IpAdd();  
           
         //判断oneAddress是否是IP  
         System.out.println(ipAdd.isIP(oneAddress));  
           
         //判断twoAddress是否是IP  
         System.out.println(ipAdd.isIP(twoAddress));  
           
         //判断threeAddress是否是IP  
         System.out.println(ipAdd.isIP(threeAddress));  
           
         //判断fourAddress是否是IP  
         System.out.println(ipAdd.isIP(fourAddress));  
    }  
  
}
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正则表达式定义了字符串的模式。

正则表达式可以用来搜索、编辑或处理文本。

正则表达式并不仅限于某一种语言,但是在每种语言中有细微的差别。

更多java知识请关注java基础教程

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