隨機數生成

package com.bwie.utils;

import java.util.Random;

public class RandomUtil {

 //生成隨機數字和字母
 public static String getStringRandom() {
 String val = "";
 Random random = new Random();

 //參數length，表示生成幾位隨機數
 for(int i = 0; i < 4; i++) {

 String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";
 //輸出字母仍是數字
 if( "char".equalsIgnoreCase(charOrNum) ) {
 //輸出是大寫字母仍是小寫字母
 int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;
 val += (char)(random.nextInt(26) + temp);
 } else if( "num".equalsIgnoreCase(charOrNum) ) {
 val += String.valueOf(random.nextInt(10));
 }
 }
 return val; }}