作者：whisper

链接：https://www.proprogrammar.com/article/984

声明：请尊重原作者的劳动，如需转载请注明出处

作者：YaoHHH

链接：https://blog.csdn.net/yh18668197127/article/details/85956811

来源：CSDN

        String password="Windows";
        String regex="^(?=W)\\w+(?<=s)$";
        Pattern p=Pattern.compile(regex);
        Matcher m=p.matcher(password);
        boolean isMatch=m.matches();
        System.out.println(isMatch);
	    
        String password2="Windows";
        String regex2="^\\w{1}(?=i)\\w+$";
        Pattern p2=Pattern.compile(regex2);
        Matcher m2=p2.matcher(password2);
        boolean isMatch2=m2.matches();
        System.out.println(isMatch2);
        
        String password3="Windows";
        String regex3="^(?!a)\\w+(?<!a)$";
        Pattern p3=Pattern.compile(regex3);
        Matcher m3=p.matcher(password3);
        boolean isMatch3=m.matches();
        System.out.println(isMatch3);
	    
        String password4="Windows";
        String regex4="^\\w{1}(?!a)\\w+$";
        Pattern p4=Pattern.compile(regex4);
        Matcher m4=p4.matcher(password4);
        boolean isMatch4=m4.matches();
        System.out.println(isMatch4);

打印结果: 

(?=params)表示正序的该位必须匹配params

(?!params)表示正序的该位必须不匹配params

(?<=params)表示用在末尾必须匹配params

(?<!params)表示用在末尾必须不匹配params

来看一个复杂的密码匹配:

6-16位数字字母混合,不能全为数字,不能全为字母,首位不能为数字

public boolean isPassword(String password){
        String regex="^(?![0-9])(?![0-9]+$)(?![a-zA-Z]+$)[0-9A-Za-z]{6,16}$";
        Pattern p=Pattern.compile(regex);
        Matcher m=p.matcher(password);
        boolean isMatch=m.matches();
        Log.i(TAG, "isPassword: 是否密码正则匹配"+isMatch);
        return isMatch;
    }
 
RuntimeTest runtimeTest=new RuntimeTest();
runtimeTest.isPassword("abcABC123");
runtimeTest.isPassword("abcdefg123456789");
runtimeTest.isPassword("abcABC");
runtimeTest.isPassword("123456");
runtimeTest.isPassword("123abcABC");

查看打印结果:

符合

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