Java生成随机字符串的代码

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();   
 }