Java产生随机数字、随机字母、随机数字+字母

package com.demo.common;


import java.util.Random;

/**
*  @version:
*        @function:        产生随机数字、随机字母、随机数字+字母。
*/
public class RandomUtil {
       
        /**
         * 随机产生几位数字：例：maxLength=3,则结果可能是 012
         */
        public static final int produceNumber(int maxLength){
                Random random = new Random();
                return random.nextInt(maxLength);
        }
       
       
        /**
         * 随机产生区间数字：例：minNumber=1,maxNumber=2,则结果可能是 1、2,包括首尾。
         */
        public static int produceRegionNumber(int minNumber,int maxNumber){
                return minNumber + produceNumber(maxNumber);
        }

        /**
         * 随机产生几位字符串：例：maxLength=3,则结果可能是 aAz
         * @param maxLength 传入数必须是正数。
         */
        public static String produceString(int maxLength){
                String source = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
                return doProduce(maxLength, source);
        }
       
        /**
         * 随机产生随机数字+字母：例：maxLength=3,则结果可能是 1Az
         * @param maxLength 传入数必须是正数。
         */
        public static String produceStringAndNumber(int maxLength){
                String source = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
                return doProduce(maxLength, source);
        }

        /**
         * 自定义随机产生结果
         */
        public static String produceResultByCustom(String customString,int maxLength){
                return doProduce(maxLength, customString);
        }
       
        /**
         * 生产结果
         */
        private static String doProduce(int maxLength, String source) {
                StringBuffer sb = new StringBuffer(100);
                for (int i = 0; i < maxLength; i++) {
                        final int number =  produceNumber(source.length());
                        sb.append(source.charAt(number));
                }
                return sb.toString();
        }
       
       
       
        public static void main(String[] args) {
                System.out.println(RandomUtil.produceNumber(3));
                System.out.println(RandomUtil.produceRegionNumber(1,2));
                System.out.println(RandomUtil.produceString(3));
                System.out.println(RandomUtil.produceStringAndNumber(3));
                System.out.println(RandomUtil.produceResultByCustom("demo.",);

        }
}
原文地址：http://bbs.it-home.org/thread-1049-1-1.html