仅使用Java创建登录系统，不使用数据库和Jpanel/Jswing

所以基本上这是家庭作业/课堂作业，我们被要求避免使用J.Frame和数据库以及所有这些东西。那么我如何创建一个有4个用户名的登录系统，每个用户都有自己的名字和姓氏呢？正如您在下面看到的，当前它只要求输入密码，而不要求输入用户名、密码以及用户的名字和姓氏。我还找到了代码，但我不确定如何添加新用户名和其他两个变量，代码是由stackoverflow上的某个人创建的，所以我不确定是否可以在这里发布

/**
 * @param args the command line arguments
 */
static Scanner s = new Scanner(System.in);
    public static void main(String[] args) throws IOException{
    // TODO code application logic here
    login("James");
    String[][] data = generateData();        
    while(true){
        System.out.println("\n1 for printing");
        System.out.println("2 for charges");
        System.out.println("3 for payment");
    System.out.println("4 for adding a new account");
        System.out.println("0 to exit");
        System.out.print("What you want to do: ");
        int input = 0;
        try{
            input = Integer.parseInt(s.nextLine());
        } catch(NumberFormatException e){
            System.out.println("Wrong input, must enter an integer!");
            continue;
        }
        if (input == 0){
            printToFile(data);
            break;
        } else{
            switch(input){
                case 1: printing(data);
                        break;
                case 2: charges(data);
                        break;
                case 3: payment(data);  
                        break;
        case 4: add(data);
            data = generateData(); 
            break;
                default: System.out.println("Wrong input, must enter 0-4!");
            }
        }
    }
}
public static void add(String[][] x) throws IOException{
System.out.print("Enter your student ID: ");
String a = s.nextLine();
System.out.print("Enter your First Name: ");
String b = s.nextLine();
System.out.print("Enter your Last Name ");
String c = s.nextLine();
    System.out.print("Enter your Contact Number: ");
String d = s.nextLine();
    System.out.print("Enter your Email Address: ");
String e = s.nextLine();
    System.out.print("Enter your Car Plate Number: ");
String f = s.nextLine();
    System.out.print("Enter Today's Date: ");
String g = s.nextLine();
    int counter = x.length;
    File data = new File("data.txt");
PrintWriter y = new PrintWriter(data);
    y.println(counter+1);
for(int i=0; i<counter; i++){
        y.println();
        y.println(x[i][0]);
        y.println(x[i][1]);
        y.println(x[i][2]);
        y.println(x[i][3]);
        y.println(x[i][4]);
        y.println(x[i][5]);
        y.println(x[i][6]);
}
y.println();
    y.println(a);
    y.println(b);
    y.println(c);
    y.println(d);
    y.println(e);
    y.println(f);
    y.println(g);
    y.close();      
}
public static void printToFile(String[][] x) throws IOException{
    int counter = x.length;
    File data = new File("data.txt");
PrintWriter y = new PrintWriter(data);
    y.println(counter);
for(int i=0; i<counter; i++){
        y.println();
        y.println(x[i][0]);
        y.println(x[i][1]);
        y.println(x[i][2]);
        y.println(x[i][3]);
        y.println(x[i][4]);
        y.println(x[i][5]);
        y.println(x[i][6]);
}
    y.close();
}
public static void login(String password){
    System.out.print("Enter your password: ");
    String input = s.nextLine();
    int i = 0;
    while(true){
        if( !(input.equals(password)) ){
            System.out.println("Wrong password!");
            if(i==1){
                System.exit(0);
            }
            System.out.println("Last chance!");                
            System.out.print("Enter your password: ");
            input = s.nextLine();
            i++;
        } else{
            break;
        }
    }
}
public static String[][] generateData() throws IOException{
    File x = new File("data.txt");
Scanner y = new Scanner(x);
    int counter = Integer.parseInt(y.nextLine());
    String[][] data = new String[counter][7];
    for(int i=0; i<counter; i++){
        y.nextLine();
        data[i][0] = y.nextLine();
        data[i][1] = y.nextLine();
        data[i][2] = y.nextLine();
        data[i][3] = y.nextLine();
        data[i][4] = y.nextLine();
        data[i][5] = y.nextLine();
        data[i][6] = y.nextLine();
}
    y.close();
    return data;
}
public static void printing(String[][] data){
    int length1 = data.length;
    int length2 = data[0].length;
    for(int i=0; i<length1; i++){
        System.out.println(" ID "+Integer.parseInt(data[i][0])+", First Name: "+data[i][1]+", Last Name: "+data[i][2]+", Contact Number: "+data[i][3]+", Email Address: "+data[i][4]+", Car Number: "+data[i][5]+", Date Registered: "+data[i][6]);
    }
}
public static void charges(String[][] data){
    int length1 = data.length;
    for(int i=0; i<length1; i++){
        System.out.println((i+1)+" for "+data[i][0]);
    }
    System.out.print("Who you want to charge: ");
    int input = Integer.parseInt(s.nextLine());
    System.out.print("How much you want to charge "+data[input-1][0]+": ");
    data[input-1][2] = ""+(Double.parseDouble(data[input-1][2]) + Double.parseDouble(s.nextLine()));
} 
public static void payment(String[][] data){
    int length1 = data.length;
    for(int i=0; i<length1; i++){
        System.out.println(" (ID "+Integer.parseInt(data[i][1]));
    }
    System.out.print("Who want to pay: ");
    int input = Integer.parseInt(s.nextLine());
    System.out.print("How much "+data[input-1][0]+" want to pay: ");
    data[input-1][2] = ""+(Double.parseDouble(data[input-1][2]) - Double.parseDouble(s.nextLine()));
}    

---

}

是否允许您将用户名/密码存储在文本文件中？您知道变量名可以超过一个字母长吗？@immibis您的意思是什么？好的，那么您使用的是哪一部分？加载文件？比较价值观？提示用户？我不知道从哪里开始，我甚至不知道你可以使用txt文件在上面写用户名：\@MadProgrammer好的，我正在搜索关于此的代码。。