随机生成字符串

public static String getRandomString(int length) { //length表示生成字符串的长度  
    String base = "abcdefghijklmnopqrstuvwxyz0123456789";     
    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();     
 }