正则表达式：密码必须包含大写字母 、数字、 特殊字符（四种里至少三种，且至少8位）
写法一：/((^(?=.*[a-z])(?=.*[A-Z])(?=.*\W)[\da-zA-Z\W]{8,16}$)|(^(?=.*\d)(?=.*[A-Z])(?=.*\W)[\da-zA-Z\W]{8,16}$)|(^(?=.*\d)(?=.*[a-z])(?=.*\W)[\da-zA-Z\W]{8,16}$)|(^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])[\da-zA-Z\W]{8,}$))/写法二：/^(?![a-zA-Z]+$)(?![A-Z0-9]+$)(?![A-Z\W_]+$)(?![a-z0-9]+$)(?![a-z\W_]+$)(?![0-9\W_]+$)[a-zA-Z0-9\W_]{8,}$/
正则表达式：密码必须包含大写字母、数字、特殊字符且至少8位（验证级别高）
^(?![A-Za-z0-9]+$)(?![a-z0-9\\W]+$)(?![A-Za-z\\W]+$)(?![A-Z0-9\\W]+$)[a-zA-Z0-9\\W]{8,20}$
使用语法
js写法示例：
var regexp = new RegExp('^(?![A-Za-z0-9]+$)(?![a-z0-9\\W]+$)(?![A-Za-z\\W]+$)(?![A-Z0-9\\W]+$)[a-zA-Z0-9\\W]{8,20}$');var newPwd = 'AAaa123@@';if(){console.log('验证通过');}else{console.log('验证不通过');}
java 写法示例：
String regexp = "^(?![a-zA-Z]+$)(?![A-Z0-9]+$)(?![A-Z\\W_]+$)(?![a-z0-9]+$)(?![a-z\\W_]+$)(?![0-9\\W_]+$)[a-zA-Z0-9\\W_]{8,16}$";if ("AAaa1234".matches(PW_PATTERN)) {System.out.println("匹配成功！");} else {System.out.println("匹配失败！");}
