Java 将字符串和 string[] 传递给另一个类

Question

我确信这个问题已经得到解答，当我搜索它时，我得到了各种各样的结果，但我就是无法理解这个概念。这是一项家庭作业，我更愿意理解这就是我发帖的原因。任务是从文件中读取用户凭据，对密码进行哈希处理，然后如果它们匹配，则显示与其角色关联的另一个文件的内容。

我在一个类中编写了这个，然后发现该作业至少需要两个类。因此，对我来说，阅读一个类中的文件并在另一个类中执行其他所有操作是有意义的。它作为一门课效果很好，但这是我的第一次编程冒险，我只上了 6 门课。我不了解我应该理解的基础知识，所以在你的回复中，如果你能告诉我为什么代码需要修改，我将不胜感激。我的代码如下；

package it145_final;
import java.util.Scanner;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class IT145_Final {

public static void main(String[] args) throws IOException, NoSuchAlgorithmException {
    Scanner scnr = new Scanner(System.in);
    Scanner fileIn = null;
    int failedAttempts = 0;
    int i = 0;
    String q = "q";
    // objects that I think I need???? Maybe??? but dont know how to get them from the FinalFiles class
    FinalFiles fileAdmin = new FinalFiles();
    FinalFiles fileVet = new FinalFiles();
    FinalFiles fileZoo = new FinalFiles();
    FinalFiles userA = new FinalFiles();
    fileAdmin.file();
    userA.file();

    while (failedAttempts < 3)
        {                
            System.out.println("Enter user name, or q to exit"); //get username
            String userName = scnr.next();     
            if (userName.equalsIgnoreCase(q)) //option to terminiate
                    {
                    System.out.println("Logging Out");
                    break;
                    }   
            System.out.println("Enter password"); // get password
            scnr.nextLine();
            String userPassword = scnr.nextLine();  
                            //The following takes the entered password and hashes it
                            String hashedPass = userPassword;  
                            MessageDigest md = MessageDigest.getInstance("MD5");
                            md.update(hashedPass.getBytes());
                            byte[] digest = md.digest();
                            StringBuffer sb = new StringBuffer();
                            for (byte b : digest) {
                            sb.append(String.format("%02x", b & 0xff));
                                    }


                if (userName.equals(userA[i]) && sb.toString().equals(userA[i + 1]))
                {
                    if (userA[i + 3].equals("admin"))
                    {
                        System.out.println(admin);
                        break;
                    }                        
                    else if (userA[i + 3].equals("veterinarian"))
                    {
                        System.out.println(veterinarian);
                        break;

                    }
                    else if (userA[i + 3].equals("zookeeper"))
                    {
                        System.out.println(zookeeper);
                        break;

                    }
                    else
                    {
                        System.out.println("Failed attempt");
                        failedAttempts ++;
                    }

                }
                if (userName.equals(userB[i]) && sb.toString().equals(userB[i + 1]))
                {
                    if (userB[i + 3].equals("admin"))
                    {
                        System.out.println(admin);
                        break;

                    }                        
                    else if (userB[i + 3].equals("veterinarian"))
                    {
                        System.out.println(veterinarian);
                        break;
                    }
                    else if (userB[i + 3].equals("zookeeper"))
                    {
                        System.out.println(zookeeper);
                        break;
                    }
                    else
                    {
                        System.out.println("Failed attempt");
                        failedAttempts ++;
                    }

                }
                if (userName.equals(userC[i]) && sb.toString().equals(userC[i + 1]))
                {
                    if (userC[i + 3].equals("admin"))
                    {
                        System.out.println(admin);
                        break;
                    }                        
                    else if (userC[i + 3].equals("veterinarian"))
                    {
                        System.out.println(veterinarian);
                        break;
                    }
                    else if (userC[i + 3].equals("zookeeper"))
                    {
                        System.out.println(zookeeper);
                        break;
                    }
                    else
                    {
                        System.out.println("Failed attempt");
                        failedAttempts ++;
                    }

                }
                if (userName.equals(userD[i]) && sb.toString().equals(userD[i + 1]))
                {
                    if (userD[i + 3].equals("admin"))
                    {
                        System.out.println(admin);
                        break;
                    }                        
                    else if (userD[i + 3].equals("veterinarian"))
                    {
                        System.out.println(veterinarian);
                        break;
                    }
                    else if (userD[i + 3].equals("zookeeper"))
                    {
                        System.out.println(zookeeper);
                        break;
                    }
                    else
                    {
                        System.out.println("Failed attempt");
                        failedAttempts ++;
                    }

                }
                if (userName.equals(userE[i]) && sb.toString().equals(userE[i + 1]))
                {
                    if (userE[i + 3].equals("admin"))
                    {
                        System.out.println(admin);
                        break;
                    }                        
                    else if (userE[i + 3].equals("veterinarian"))
                    {
                        System.out.println(veterinarian);
                        break;
                    }
                    else if (userE[i + 3].equals("zookeeper"))
                    {
                        System.out.println(zookeeper);
                        break;
                    }
                    else
                    {
                        System.out.println("Failed attempt");
                        failedAttempts ++;
                    }

                }
                if (userName.equals(userF[i]) && sb.toString().equals(userF[i + 1]))
                {
                    if (userF[i + 3].equals("admin"))
                    {
                        System.out.println(admin);
                        break;
                    }                        
                    else if (userF[i + 3].equals("veterinarian"))
                    {
                        System.out.println(veterinarian);
                        break;
                    }
                    else if (userF[i + 3].equals("zookeeper"))
                    {
                        System.out.println(zookeeper);
                        break;
                    }
                    else
                    {
                        System.out.println("Failed attempt");
                        failedAttempts ++;
                    }

                }


        System.out.println("Login Failed");
        failedAttempts++;
        }







    }




}

您可以看到我开始创建一些对象，但我只是不知道如何从其他类(class)获取信息，或者这是否是一个好方法。我创建的用于读取文件的类是；

package it145_final;
import java.io.File;
import java.io.IOException;
import java.util.Scanner;


public class FinalFiles {
     public static void file() throws IOException{


    String admin = "";
    String veterinarian = "";
    String zookeeper = "";
    String[] userA = new String[4];
    String[] userB = new String[4];
    String[] userC = new String[4];
    String[] userD = new String[4];
    String[] userE = new String[4];
    String[] userF = new String[4]; 

        File file0 = new File("C:usercredentials.txt"); // Opens files
            Scanner contents0 = new Scanner(file0);
        File file1 = new File("C:admin.txt"); 
            Scanner contents1 = new Scanner(file1);
        File file2 = new File("C:veterinarian.txt"); 
            Scanner contents2 = new Scanner(file2);
        File file3 = new File("C:zookeeper.txt"); 
            Scanner contents3 = new Scanner(file3);

            // Following reads the files and assignes to variables as needed
            while (contents1.hasNext())
                {     
                    admin += contents1.nextLine();   
                }
           // System.out.println(admin); used to verify that admin was correct
            while (contents2.hasNext())
                {        
                    veterinarian += contents2.nextLine();   
                }
            while (contents3.hasNext())
                {    
                    zookeeper += contents3.nextLine();   
                }              
            while(contents0.hasNext())
                {                
                    String user1 = contents0.nextLine();//grabs the line from the file for each individual user
                    String user2 = contents0.nextLine();
                    String user3 = contents0.nextLine();
                    String user4 = contents0.nextLine();
                    String user5 = contents0.nextLine();
                    String user6 = contents0.nextLine();
                    userA = user1.split("\t");//takes information on user and breaks it into an array                       
                    userB = user2.split("\t");
                    userC = user3.split("\t");
                    userD = user4.split("\t");
                    userE = user5.split("\t");
                    userF = user6.split("\t");

                System.out.println(userB[0]);  //using for testing to make sure I am getting the correct info
                System.out.println(userB[1]);

                }

     }

}

我知道它不整洁，我确信我有更好的方法来写这样的东西，我只是做了我想到的和我知道的。我认为如果有人可以向我展示如何将这些字符串(管理员、 vert 和动物园管理员)以及 String[]、userA userB 等传递到我的 main 中，那么它会再次起作用，并且对于具有我的技能水平的人来说已经足够了。

干杯安迪

Answer 1

由于您处于入门级编码阶段，我会尽力帮助您理解一些逻辑，这对于制作良好的应用程序至关重要。

为了让自己更轻松，您应该认为每个任务都需要一个类。在你的情况下，你应该有一个类用于获取文件，另一个类用于检查密码。请记住，始终有一个主导类启动应用程序并包含 main 方法。

在这些单独的类中，您应该创建方法来分解流程，使代码更加清晰。在密码检查类中，您需要为每个作业提供一个方法(读取文件、加密密码、解密密码、相互检查凭据)。

然后将值返回给第一个类。所以它看起来像这样。

class Main { //first class
    public static void main(String[] args){
        File = new File("file1"); //obtain file 1
        File = new File("file2"); //obtain file 2
        PasswordCheck checker = new PasswordCheck(); // call instance of second class

        boolean credentialOk= passwordCheck.process(file1,file2)//calls method in second class and returns if the credentials match
    }
}

class PasswordCheck { //second class
   public passwordCheck(){

   }//inistialise class

   public boolean process(File file1, File file2){

   }// method to process the files and returns if match succesfully or not 
}