JAVA 随机字符串生成方法
http://hi.baidu.com/yinfuqing666/blog/item/b9c3a0d21917e00e3af3cf28.html
http://hi.baidu.com/samuel_vong/blog/item/95471f7e2cdab33d0cd7dad1.html

实现方法一：
引用

public class RandomFileName {       /**      * 产生一个随机的字符串      *        * @param 字符串长度      * @return      */     public static String getRandomString(int length) {           String base = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";           Random random = new Random();           StringBuffer sb = new StringBuffer();           for (int i = 0; i < length; i++) {               int number = random.nextInt(base.length());               sb.append(base.charAt(number));           }           return sb.toString();       }       public static void main(String[] args) {           System.out.println(RandomFileName.getRandomString(5));       }   }

public class RandomFileName2 {       /**      * 产生一个随机的字符串      *        * @param 字符串长度      * @return      */     public static String getRandomString(int length) {           Random random=new Random();           StringBuffer sb=new StringBuffer();           for(int i=0;i<length;i++){               int number=random.nextInt(3);               long result=0;               switch(number){                   case 0:                       result = Math.round(Math.random()*25+65);                       sb.append(String.valueOf((char)result));                       break;                   case 1:                       result = Math.round(Math.random()*25+97);                       sb.append(String.valueOf((char)result));                       break;                   case 2:                       sb.append(String.valueOf(new Random().nextInt(10)));                       break;               }           }           return sb.toString();       }              public static void main(String[] args) {           System.out.println(RandomFileName2.getRandomString(10));       }   }