java常用工具 分享一些Java的常用工具

package com.lucun.student.utils;

import java.util.Random;
//纯数字验证码
public class GetRandom {
    public static String getFourRandom(){
        Random random = new Random();
        String fourRandom = random.nextInt(10000) + "";
        int randLength = fourRandom.length();
        if(randLength<6){//这个6代表生成6位随机数
            for(int i=1; i<=6-randLength; i++)
                fourRandom = "0" + fourRandom ;
        }
        return fourRandom;
    }
}

package com.lucun.student.utils;

import java.util.Random;

public class GetRandomEnglishMath {
    public static String getCharAndNumr(int length) {
        String val = "";
        Random random = new Random();
        for (int i = 0; i < length; i++) {
            String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";
            if ("char".equalsIgnoreCase(charOrNum)) {
                // 取得大写字母还是小写字母
                int choice = random.nextInt(2) % 2 == 0 ? 65 : 97;
                val += (char) (choice + random.nextInt(26));
            }else if ("num".equalsIgnoreCase(charOrNum)) { // 数字
                val += String.valueOf(random.nextInt(10));
            }
        }
        return val;
    }
}

"^([a-z0-9A-Z]+[-|_|\\.]?)+[a-z0-9A-Z]@([a-z0-9A-Z]+(-[a-z0-9A-Z]+)?\\.)+[a-zA-Z]{2,}$"