Question

我正在从事学校的ATM Java任务，我被困住了。在子类 Bank 中，我有一个HashMap变量， theBank ，方法 createAccount 用于添加到地图中。接口由赋值规范预先确定，包括HashMap的静态状态：

import java.util.HashMap;
public class Bank {

public static HashMap<String, BankCustomer> theBank;

public Bank ()
{
    theBank = new HashMap<String, BankCustomer> ();
}
/**
 * Method createAccount.
 * To add a new BankCustomer element to the HashMap.
 * Uses the account number as the key and the new BankCustomer as the value.
 * @param newCustomer to input a BankCustomer for the HashpMap 
 * 
 */
public void createAccount(BankCustomer newCustomer)
{
    if (newCustomer != null){   
        theBank.put(newCustomer.getAccountNumber(), newCustomer);
    }
}

我需要在主驱动程序类的方法中初始化HashMap：

/**
 * Method initialize
 * To add Customer references to the Bank HashMap as seed data for testing
 */
public void initialize() 
{   
    Bank testBank = new Bank (); //initialize HashMap from Bank class

    //seed the HashMap with a few objects
    BankCustomer a = new BankCustomer("David", "Jones", "A001", "547");
    BankCustomer b = new BankCustomer("Alice", "Stone", "A002", "777"); 
    //seed the HashMap
    testBank.createAccount(a);
    testBank.createAccount(b);
}

这是驱动程序类的默认构造函数（run（）方法是case / switch例程）：

public class ATM {

/**
 * Default constructor of class ATM. 
 * Calls the initialize() method to seed the Bank with some BankCustomers. 
 * Calls the run() method to perform the primary program functions.
 */
public ATM ()
{
    initialize();
    run();  
}

主要的驱动方法是：

public static void main(java.lang.String[] args)
{
    new ATM();
}

我的问题是在我的ATM类方法中，我无法访问Bank HashMap变量， testBank ; ＆＃34; testBank无法解决。＆＃34;以下是testBank未解决的方法之一：

/**
 * Method verifyCustomer
 * To confirm a BankCustomer's account number and passcode.
 * Called when the user is required to sign in to the application. 
 * Will set a boolean so the user does not have to sign in again during the session.
 */
public void verifyCustomer()
{
    InputReader reader = new InputReader ();
    boolean isVerified = false;
    if(isVerified ==  false){
        System.out.println("Enter Account Number: ");
        String accountNumber = reader.getStringInput();
        for(String accounts: testBank.keySet()){
            if(accounts.equals(accountNumber)){
                BankCustomer customer = testBank.get(accounts);
                String code = customer.getPasscode();
                System.out.println("Enter Passcode: ");
                String passcode = reader.getStringInput();
                if(code.equals(passcode)){
                    isVerified = true;
                }
                else{
                    System.out.println("Incorrect passcode.");
                    isVerified = false;
                }
            }
            else{
                System.out.println("Account not found.");
                isVerified = false;
            }
        }
    }
}

我是否正在初始化HashMap并在 initialize（）方法中正确播种？有什么建议 testBank 没有解决？如何使HashMap的范围足够宽，以便在ATM类方法中解决？

非常感谢。

Answer 1

根据你在问题中所写的内容，我知道为什么会失败：

public void initialize（）{
Bank testBank = new Bank（）; //从Bank类
初始化HashMap

这是您的问题开始的地方。你是用你的本地方法创建的，但是你不能把它保存在任何地方。您需要具有私有参数或其他形式的体系结构。这根本不适用于编译时间。

从驱动程序类初始化静态HashMap，并扩展其范围

1 个答案: