生成x位随机数字密码、验证码、字符密码

1.生成x位随机数字密码

public String getRandomNum (int length){

String num = "";
for (int i=0;i<length;i++){
Integer a = (int)(Math.random ()*10);
num = num+a.toString ();
}
//打印结果
System.out.println (num);
return num;
}
可自行添油加醋，添加判断逻辑。

2.生成随机位数字符密码或验证码

public String getRandomString(int length) {
String str= "ABCDEFGHIJKLMNOPQRSTUVWXYZ123456";
Random random = new Random();
StringBuffer sbbf = new StringBuffer();
for (int i = 0; i < length; i++) {
int number = random.nextInt(str.length());
sbbf.append(str.charAt(number));
}
System.out.println (sbbf.toString());
return sbbf.toString();
}