正则表达式，split

package com.company.project.builder;import java.util.Arrays;//  \d  数字字符， \w单词字符  \s 空白字符  \D  非数字 \W 非单词字符//java里多加一个\以转义\  ，例如\\d 代表数字字符public class StringDemo {    public static void main(String[] args) {        //匹配邮箱        String str = "[a-zA-Z\\d_]+@[a-zA-Z\\d_]+(\\.[a-zA-Z\\d_]+)+";        String mail = "[e-mail]3";        System.out.println(mail.matches(str));        //身份证号        String str1 = "\\d{15}(\\d{2}[\\dxX])?";        String id  = "340622222233330";        System.out.println(id.matches(str1));        //split方法，前面的逗号保留空元素，后面的不保留        //执行结果：[, , zhangsan, lisi, , , wangwu, zhaoliu]        String str2 = ",,zhangsan,lisi,,,wangwu,zhaoliu,,,";        System.out.println(Arrays.toString(str2.split(",")));        //数字替换为#num#        String str3 = "dsfh23oisa333hfoid45656saghoifdah324giodsagfsd5paohf";        System.out.println(str3.replaceAll("\\d+", "#num#"));        //把“帐号|密码|身份证号”替换为***        String str4 = "你好，银行帐号，密码，身份证号分别是多少？";        String str5 = "帐号|密码|身份证号";        System.out.println(str4.replaceAll(str5, "***"));    }}