Java 中正则的应用

最新推荐文章于 2024-11-10 19:08:29 发布

shenzhenNBA

最新推荐文章于 2024-11-10 19:08:29 发布

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分类专栏： Java 文章标签：正则 Java regex

本文链接：https://blog.youkuaiyun.com/shenzhenNBA/article/details/8562445

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本文介绍了Java中使用正则表达式的简单方法，并提供了几个常见字符串验证功能的实现，包括检查是否全为数字字符、字母字符、数字字母、下划线、连字符和数字字母组合，以及邮箱地址验证。

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更多Java 正则知识参见： https://docs.oracle.com/javase/6/docs/api/java/util/regex/Pattern.html

Java中使用正则很简单，主要分两步进行：

1，涉及的类，需要引入如下两个正则相关的类

import java.util.regex.Matcher;
import java.util.regex.Pattern;

2，定义正则匹配模式，编译，进行匹配操作和匹配结果使用

//(1), String xchar = "123"; //将进行匹配的变量
//(2), String numCharPattern = "[0-9]"; //正则匹配模式
//(3), Pattern pattern = Pattern.compile(numCharPattern); //编译正则
//(4), Matcher mat = pattern.matcher(xchar); //进行匹配操作
//(5), if(mat.find()){ //匹配结果使用,符合正则模式则返回true，否则返回false
//	System.out.println("符合正则匹配"); 
//     }else{ 
//	System.out.println("不符合 正则匹配"); 
//     }

如下常用例子:

package com.gc.fun;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * The class GlobalFuns. supply the global function to use. 
 *
 * @author: shenzhenNBA
 * @since: 2013-02-01	
 * @version: $Revision$ $Date$ $LastChangedBy$
 *
 */
public class GlobalFuns {

	public static boolean isNumberChar(String value) {
		//function: to check all value is number char or not
		//true = all is only number char, 
		//false = not all are number char  

		boolean tag = true;
		String numCharPattern = "[0-9]";
		Pattern pattern = Pattern.compile(numCharPattern);
		char[] chars = value.toCharArray();
		for (char c : chars) {
			Matcher mat = pattern.matcher(String.valueOf(c));
			if (!mat.find()) {
				tag = false;
			}
		}
		return tag;
	}
		
	public static boolean isLetterChar(String value) {
		//function: to check all value is letter char or not
		//true = all char is range of [a-zA-Z]; 
		//false = at lest one char is out of char range[a-zA-Z]
		boolean tag = true;
		String numCharPattern = "[a-zA-Z]";
		Pattern pattern = Pattern.compile(numCharPattern);
		char[] chars = value.toCharArray();
		for (char c : chars) {
			Matcher mat = pattern.matcher(String.valueOf(c));
			if (!mat.find()) {
				tag = false;
				break;
			}
		}
		return tag;
	}
		
	public static boolean isNumberLetterUnderlineMinusChar(String value) {
		//function: to check all value is range of [0-9a-zA-Z_-] or not
		//true = all char is range of [0-9a-zA-Z_-](number or letter or underline or minus); 
		//false = at lest one char is out of char range[0-9a-zA-Z_-]
		boolean tag = true;
		String numCharPattern = "[0-9a-zA-Z_-]";
		Pattern pattern = Pattern.compile(numCharPattern);
		char[] chars = value.toCharArray();
		for (char c : chars) {
			Matcher mat = pattern.matcher(String.valueOf(c));
			if (!mat.find()) {
				tag = false;
				break;
			}
		}
		return tag;
	}
	
	public static  boolean isLegalEmail(String email) {
		//function: to check param email is legal or not
		//true = is legal eamil address
		//false = not legal email address

		boolean tag = true;
		String emailPattern ="^([a-zA-Z0-9_\\-\\.]+)@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.)|(([a-zA-Z0-9\\-]+\\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\\]?)$";
		Pattern pattern = Pattern.compile(emailPattern);
		Matcher mat = pattern.matcher(email);
		if (!mat.find()) {
			tag = false;
		}
		return tag;
	}
	
	public static  boolean isNumberLetterChar(String value) {
		//function: to check value is range of [0-9a-zA-Z] or not
		//true = all char are range of range [0-9a-zA-Z]
		//false = at least one char is out of range [0-9a-zA-Z]

		boolean tag = true;
		String numCharPattern = "[0-9a-zA-Z]";
		Pattern pattern = Pattern.compile(numCharPattern);
		char[] chars = value.toCharArray();
		for (char c : chars) {
			Matcher mat = pattern.matcher(String.valueOf(c));
			if (!mat.find()) {
				tag = false;
			}
		}
		return tag;
	}	

	//can expand here
}

只要继承该类，即可直接使用已有的数字，字母，数字字母，email等验证功能，方便快速使用。