小编use*_*456的帖子

所以我有以下数组:

String [] randomList = new String [16];
    randomList[0]="Dog";
    randomList[1]="Dog";
    randomList[2]="Cat";
    randomList[3]="Cat";
    randomList[4]="Mouse";
    randomList[5]="Mouse";
    randomList[6]="Car";
    randomList[7]="Car";
    randomList[8]="Phone";
    randomList[9]="Phone";
    randomList[10]="Game";
    randomList[11]="Game";
    randomList[12]="Computer";
    randomList[13]="Computer";
    randomList[14]="Toy";
    randomList[15]="Toy";

我想只改变这个数组的前9个元素.我使用了以下代码,但它将整个数组洗牌.

Collections.shuffle(Arrays.asList(randomList));

我怎么会只改变阵列的一部分而不是整个东西呢？我正在制作一个非常简单的程序,所以我想继续使用Collections类,但欢迎所有解决方案.谢谢

我在java中创建一个简单的登录程序.这是我到目前为止的代码.

import java.util.Scanner;
import java.io.*;
import java.util.Arrays;

public class PasswordProgram {

    public static String user;
    public String password;
    public static boolean part1Finish = false;
    public File file = new File("D:/file.txt");
    public FileWriter UsernameWrite;
    public char[] user1;

    public void part1() {
        System.out.println("Please create an account: ");
        Scanner input = new Scanner(System. in );
        System.out.println("Type in a username: ");
        String user = input.next();

        System.out.println("Type in a Password: ");
        String password = input.next();
        try {
            UsernameWrite = new FileWriter(file);
            UsernameWrite.write(user);
            UsernameWrite.write(password);
            System.out.println(user);
            UsernameWrite.close(); …