32. Random class

1.Random

class Random implements java.io.Serializable

Here is the code for a simple captcha:

public  static  void main(String[] args) {
         // Do a simple verification code 
        char [] charr = {'q','Q','F','f','d','kind',' in','over' };
        String str = "";
        Random random = new Random();
        for(int i = 0; i < 4; i++) {
            str + = charr [random.nextInt (charr.length)];
        }
        System.out.println(str);
}

 

Note: nextInt calls this method to return the specified range of data of type int

　　If you want to call other types, you only need to call the corresponding method