一、需求:密码必须是包含大写字母、小写字母、数字、特殊符号(不是字母,数字,下划线,汉字的字符)的8位以上组合
二、方案:利用正则表达式来校验
三、思路:排除法
1、排除大写字母、小写字母、数字、特殊符号中1种组合、2种组合、3种组合,那么就只剩下4种都包含的组合了
2、表达式为:^(?![A-Za-z0-9]+$)(?![a-z0-9\\W]+$)(?![A-Za-z\\W]+$)(?![A-Z0-9\\W]+$)[a-zA-Z0-9\\W]{8,}$
3、拆分解释:其中(2)-(6)运用了零宽断言、环视等正则功能
(1)^匹配开头
(2)(?![A-Za-z0-9]+$)匹配后面不全是(大写字母或小写字母或数字)的位置,排除了(大写字母、小写字母、数字)的1种2种3种组合
(3)(?![a-z0-9\\W]+$)同理,排除了(小写字母、数字、特殊符号)的1种2种3种组合
(4)(?![A-Za-z\\W]+$)同理,排除了(大写字母、小写字母、特殊符号)的1种2种3种组合
(5)(?![A-Z0-9\\W]+$)同理,排除了(大写字母、数组、特殊符号)的1种2种3种组合
(6)[a-zA-Z0-9\\W]匹配(小写字母或大写字母或数字或特殊符号)因为排除了上面的组合,所以就只剩下了4种都包含的组合了
(7){8,}8位以上
(8)$匹配字符串结尾
public class RegexTest {
//包含大小写字母,数字,特殊字符 且至少出现一次
public static final String PW_PATTERN = "^(?![A-Za-z0-9]+$)(?![a-z0-9\\W]+$)(?![A-Za-z\\W]+$)(?![A-Z0-9\\W]+$)[a-zA-Z0-9\\W]{8,}$";
//包含大写字母,数字,特殊字符 且至少出现一次
public static final String PW_PATTERN2 = "^(?![A-Za-z0-9]+$)(?![a-z0-9\\W]+$)(?![A-Z\\W]+$)[a-zA-Z0-9\\W]{8,}$";
public static void main(String[] args) {
String pw1 = "ABCDEFGHIG";
String pw2 = "abcdefghig";
String pw3 = "0123456789";
String pw4 = "!@#$%^&*()";
String pw5 = "ABCDEabcde";
String pw6 = "ABCDE01234";
String pw7 = "ABCDE!@#$%";
String pw8 = "abcde01234";
String pw9 = "abcde!@#$%";
String pw10 = "01234!@#$%";
String pw11 = "abcde01234!@#$%";
String pw12 = "ABCDE01234!@#$%";
String pw13 = "ABCDEabcde!@#$%";
String pw14 = "ABCDEabcde01234";
String pw15 = "Aa0!";
//符合要求密码
String pw16="ABCabc012!@#";
System.out.println(pw1.matches(PW_PATTERN));
System.out.println(pw2.matches(PW_PATTERN));
System.out.println(pw3.matches(PW_PATTERN));
System.out.println(pw4.matches(PW_PATTERN));
System.out.println(pw5.matches(PW_PATTERN));
System.out.println(pw6.matches(PW_PATTERN));
System.out.println(pw7.matches(PW_PATTERN));
System.out.println(pw8.matches(PW_PATTERN));
System.out.println(pw9.matches(PW_PATTERN));
System.out.println(pw10.matches(PW_PATTERN));
System.out.println(pw11.matches(PW_PATTERN));
System.out.println(pw12.matches(PW_PATTERN));
System.out.println(pw13.matches(PW_PATTERN));
System.out.println(pw14.matches(PW_PATTERN));
System.out.println(pw15.matches(PW_PATTERN));
System.out.println(pw16.matches(PW_PATTERN));
}
}
输出结果除最后一行外全是false,即只有最后一个密码是符合要求的