java - 密码随机生成器 : creates the same password

Question

重点是创建一个密码随机化器，但我的问题是我的代码始终创建相同的密码。我尝试过各种各样的东西，这是我通过互联网获得的最新的东西。

主类:

class Program {
    public static void main(String[] args) {
        PasswordRandomizer randomizer = new PasswordRandomizer(13);
        System.out.println("Password: " + randomizer.createPassword());
        System.out.println("Password: " + randomizer.createPassword());
        System.out.println("Password: " + randomizer.createPassword());
        System.out.println("Password: " + randomizer.createPassword());
    }
}

Program 类:

import java.util.Random;
public class PasswordRandomizer {
    // Define the variables

    private Random password = new Random();
    private int length;
    private String character; 

    public PasswordRandomizer(int length) {
        //creates a new object, uses the given password length
        this.length = length;

        String characters = "";

            Random rndNumbers = new Random();
            int randomnumber = 0;


            for (int nbr = 1; nbr < length; nbr++) {
                randomnumber = rndNumbers.nextInt(25);

                char character = "abcdefghijklmnopqrstuvwxyz".charAt(randomnumber);
                characters = characters + character; 
            }

        System.out.println(characters);
        this.character = characters;
    }


    public String createPassword() {
        // write code that returns a randomized password
        PasswordRandomizer randomizer = new PasswordRandomizer(13);
        //consists of symbols a-z and is of the length given as a parameter to the constructor
        return this.character;  
    }
}

在PasswordRandomizer方法中，有一行System.out.println(characters);每次都会打印出随 secret 码。但是不同的密码不会出现在 createPassword 方法中，只有第一个密码会在输出中始终产生相同的密码。

Answer 1

正如我在评论中提到的，您的方法 createPassword() 调用构造函数并创建一组新的实例变量，这些变量会丢失。将“随机化”代码移至此方法可以解决此问题。查看sample at Ideone 。修改后的构造函数和 createPassword() 代码如下。

public PasswordRandomizer (int length) {
        //creates a new object, uses the given password length
        this.length = length;

}     

public String createPassword() {
        String characters = "";

        Random rndNumbers = new Random();
        int randomnumber = 0;
        for (int nbr = 1; nbr < length; nbr++) {
            randomnumber = rndNumbers.nextInt(25);
            char character = "abcdefghijklmnopqrstuvwxyz".charAt(randomnumber);
            characters = characters + character; 
        }

        System.out.println(characters);
        return characters;  
}