Java:登录系统无法工作

Question

我一直在为我的游戏制作一个登录系统原型(prototype)，遗憾的是它不起作用!我不知道为什么，但这是我的代码:

这是我的主类的代码:`

package darkbyte.tests;

import java.util.Scanner;

public class Main {

    private static FileCreator creator = new FileCreator();
    private static FileReader reader = new FileReader();

    private static void login() {
        Scanner input = new Scanner(System.in);

        boolean passwordExists;

        System.out.println();
        System.out.println("Please enter your username: ");
        String username = input.nextLine();
        System.out.println("Please enter your password: ");
        String password = input.nextLine();

        reader.openFile(username + ".user");
        if(reader.doesStringExist(password)) {
            passwordExists = true;
        } else {
            passwordExists = false;
        }

        reader.closeFile();

        if(passwordExists) {
            System.out.println("Welcome back to Darkbyte " + username + "!");
        } else {
            System.out.println("The password you entered is incorrect!");
            login();
        }
    }

    private static void register() {
        Scanner input = new Scanner(System.in);

        System.out.println();
        System.out.println("Please enter the username you desire: ");
        String username = input.nextLine();
        System.out.println("Please enter the password you desire: ");
        String password = input.nextLine();

        creator.openFile(username + ".user");
        creator.writeString(username);
        creator.writeString(password);
        creator.closeFile();
    }

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.println("Welcome to Darkbyte!");
        System.out.println("Would you like to login or register an account?"); 
        System.out.println("Enter 0 to login and any other number to register: ");
        int choice = input.nextInt();

        if(choice == 0) {
            login();
        } else {
            register();
        }
    }
}

这是我的 FileCreator 类的代码:

package darkbyte.tests;

import java.io.*;

import java.util.*;

public class FileCreator {

    private Formatter format;

    public void openFile(String file) {
        try {
            format = new Formatter(file);
        } catch(Exception e) {
            System.err.println("Darkbyte: There was an error in opening the file!");
        }
    }

    public void closeFile() {
       format.close();
    }

    public void writeInteger(int i) {
        format.format("%i%n", i);
    }

    public void writeFloat(float f) {
        format.format("%f%n", f);
    }

    public void writeString(String s) {
        format.format("%s%n", s);
    }

    public void appendInt(String file, int i) {
        try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(file, true)))) {
            out.println(i);
        }catch (IOException e) {
            System.err.println("Darkbyte: Couldn't find file!");
        }
    }

    public void appendFloat(String file, float f) {
        try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(file, true)))) {
            out.println(f);
        }catch (IOException e) {
            System.err.println("Darkbyte: Couldn't find file!");
        }
    }

    public void appendString(String file, String s) {
        try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(file, true)))) {
            out.println(s);
       }catch (IOException e) {
             System.err.println("Darkbyte: Couldn't find file!");
        }
    }
}

这是我的 FileReader 类的代码:

package darkbyte.tests;

import java.io.*;

import java.util.*;

public class FileReader {

    private Scanner scanner;

    public void openFile(String file) {
        try {
            scanner = new Scanner(new File(file));
        } catch(Exception e) {
            System.err.println("Darkbyte: Couldn't find file!");
        }
    }

    public void closeFile() {
        scanner.close();
    }

    public void readInt(int i, int lookingFor) {
        while(i != lookingFor) {
            if(scanner.hasNext()) {
                i = Integer.parseInt(scanner.next());
            }
        }
    }

    public void readFloat(float f, float lookingFor) {
        while(f != lookingFor) {
            if(scanner.hasNext()) {
                f = Float.parseFloat(scanner.next());
            }
        }
    }

    public void readString(String s, String lookingFor) {
        while(s != lookingFor) {
            if(scanner.hasNext()) {
                s = scanner.next();
            }
        }
    }

    public boolean doesIntExist(int i) {
        boolean intIsFound = false;
        int tempInt;

        while(scanner.hasNext()) {
            if(!intIsFound) {
                tempInt = Integer.parseInt(scanner.next());
                if(tempInt == i) {
                    intIsFound = true;
                } else {
                    intIsFound = false;
                }
            }
        }

        return intIsFound;
    }

    public boolean doesFloatExist(float f) {
        boolean floatIsFound = false;
        float tempFloat;

        while(scanner.hasNext()) {
            if(!floatIsFound) {
                tempFloat = Float.parseFloat(scanner.next());
                if(tempFloat == f) {
                    floatIsFound = true;
                } else {
                    floatIsFound = false;
                }
            }
        }

        return floatIsFound;
    }

    public boolean doesStringExist(String s) {
        boolean stringIsFound = false;
        String tempString;

        while(scanner.hasNext()) {
            if(!stringIsFound) {
                tempString = scanner.next();
                if(tempString == s) {
                    stringIsFound = true;
                } else {
                    stringIsFound = false;
                }
            }
        }

        return stringIsFound;
    }
}

问题是，当我尝试登录时，即使我的用户名和密码正确，它仍然显示我的详细信息不正确!

我不知道为什么，但你能帮我吗？

Answer 1

我认为错误在于

if(tempString == s) {
    stringIsFound = true;
} else {
    stringIsFound = false;
}

将其更改为:

if(tempString.equals(s)) {
    stringIsFound = true;
} else {
    stringIsFound = false;
}

比较字符串时始终使用equals，否则您比较的是它们的引用而不是它们的值。