java生成验证码

方法1

package nm;
import java.util.Scanner;
import java.util.Random;
public class mmm {
    public static void main(String[] args) {
//随机生成验证码
        Random a = new Random();
        char[] w = new char[5];
        for (int i = 0; i < w.length; i++) {
            if (i % 2 == 0) {
                w[i] = (char) (a.nextInt(27) + 97);//小写字母
            } else if (i != 3 && i % 2 == 1)
                w[i] = (char) (a.nextInt(27) + 65);//大写字母

            else {
                w[i] = (char) (a.nextInt(10)+48);//数字
            }
                System.out.print(w[i]);//显示出验证码
        }
        String d=new String(w);//将存放验证码的char数组转化为String
        Scanner cin=new Scanner(System.in);
        String c=cin.nextLine();//输入的字符
        System.out.println(c.equals(d));//判断验证码和输入的是否相同
    }

}

方法2

package nm;
import java.util.Scanner;
import java.util.Random;
public class mmm {
    public static void main(String[] args) {
Random p=new Random();
        String b = "qwertyuiopasdfghjklzxcvbnm1234567890";
        char a[] = new char[5];
        for (int i = 0; i < a.length; i++)
        {a[i] = b.charAt(p.nextInt(b.length()));//从b里随机取一个字符赋给a
     System.out.print(a[i]);}
        String c=new String(a);
        Scanner d=new Scanner(System.in);
        String e=d.nextLine();
        System.out.print(c.equals(e));
    }
}