//创建输出所有范围的字符串
String arr = "0123456789abcdefghijklmnopqrstuvwxyzABCDENGHIJKLMNOPQRSTUVWXYZ";
//创建随机数
Random Num = new Random();
//创建验证码数组
char[] m = new char[6];//6:6位验证码数组
//定义验证码字符串
String code = "";
//遍历验证码
for (int i = 0; i < m.length; i++) {
int num = Num.nextInt(62);
m[i] = (char)arr.charAt(num);
code = code +String.valueOf(m[i]);
}
System.out.println(code);
System.out.print("请输入验证码:");
//输入验证码
Scanner put = new Scanner(System.in);
//随机验证码与输入验证码全小写
String input = put.nextLine().toLowerCase();
String output = code.toLowerCase();
//判断
if(input.equals(output)){
System.out.println("验证码正确");
}else{
System.out.println("验证码错误");
}