Here you can find the source of getRandomStr(int Len)
public static String getRandomStr(int Len)
//package com.java2s; //License from project: Apache License import java.util.Random; public class Main { public static String getRandomStr(int Len) { String[] baseString = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" }; Random random = new Random(); int length = baseString.length; String randomString = ""; for (int i = 0; i < length; i++) { randomString += baseString[random.nextInt(length)]; }/*from w w w . j ava 2 s .c o m*/ random = new Random(System.currentTimeMillis()); String resultStr = ""; for (int i = 0; i < Len; i++) { resultStr += randomString.charAt(random.nextInt(randomString .length() - 1)); } return resultStr; } }