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();  
 }