UUIDUtils

package com.java.activiti.util;

import java.util.Random;
import java.util.UUID;

public class UUIDUtils {
    
    /**
     * uuid
     * @return
     */
    public static String getUUID(){
        String id = UUID.randomUUID().toString().replaceAll("-","");
        return id;
    }
    
    /**
     * 六位随机数
     * @param pwd_len
     * @return
     */
    public static String getRandomNum(int pwd_len){
        //35是因为数组是从0开始的，26个字母+10个数字
        final int maxNum = 36;
        int i; //生成的随机数
        int count = 0; //生成的密码的长度
        char[] str = { ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘7‘, ‘8‘, ‘9‘ };
 
        StringBuffer pwd = new StringBuffer("");
        Random r = new Random();
        while(count < pwd_len){
            //生成随机数，取绝对值，防止生成负数，
            i = Math.abs(r.nextInt(maxNum)); //生成的数最大为36-1
            if (i >= 0 && i < str.length) {
                pwd.append(str[i]);
                count ++;
            }
        }
 
        return pwd.toString();
    }

}