java实现验证码的功能

package com.ityx.d3_static_test;import java.util.Random;public class VerifyTool { //private VerifyTool(){} public static void main(String[] args) { System.out.println("验证码：" + createCode(5)); } public static String createCode(int n){ String chars = "abcdefghijklmnoqprstuvwxyzABCDEFGHIJKLMNOQPRSTUVWXYZ0123456789"; String code = ""; Random r = new Random(); for(int i = 0;i