Java: 搜索时未返回 ArrayList 项目

Question

我试图在我的主要方法中概述 ArrayList 个银行账户，调用对该列表中所有账户的搜索，如果该账户存在...存款。程序的实际规格：

设计并实现一个按以下方式执行的程序：

• 程序启动时，会创建两个银行帐户，使用姓名和写入代码的数字；

• 然后要求用户输入帐号，然后输入金额存入该帐户；

• 相应帐户的余额随后会相应更新—或者如果输入了不正确的帐号会显示一条消息； 规范的搜索部分让我很不爽。

• 然后询问用户是否希望进行更多存款；

• 如果用户回答确实希望进行更多存款，则流程继续；

• 如果用户不希望进行更多存款，则两个帐户的详细信息显示（帐号、账户名和余额）。

当我运行当找不到帐户时它 returns 输出的代码...显然我正在定义的帐户没有像我期望的那样被转移到 ArrayList .

银行账户class:

import java.util.ArrayList;

public class BankAccount {

     // the attributes
       private String accountNumber;
       private String accountName;
       private double balance;
       private char choice;
       
       //Notice the static attribute
       private static double interestRate;

       // the methods

       // the constructor
       public BankAccount(String numberIn, String nameIn)
       {
          accountNumber = numberIn;
          accountName = nameIn;
          balance = 0;
       }

       // methods to read the attributes
       public String getAccountName()
       {
          return accountName;
       }

       public String getAccountNumber()
       {
          return accountNumber;
       }

       public double getBalance()
       {
          return balance;
       }

       // methods to deposit and withdraw money
       public void deposit(double amountIn)
       {
          balance = balance + amountIn;
       }

       public void withdraw(double amountIn)
       {
         if (amountIn > balance) 
         {
             System.out.println("Sorry, there is an insufficient amount in your account to complete this withdrawal");
         } 
         else 
            {
             System.out.println("Withdrawal Successful");
             balance = balance - amountIn;
            }
       }
       
       public void setInterestRate(double rateIn)
       {  
          interestRate = rateIn;
       }
       
        public double getInterestRate()
       {  
          return interestRate;
       }
       
        public void addInterest()
       {  
         balance = balance + (balance *interestRate)/100;
       }
        
        
      
}

银行Class:

import java.util.ArrayList;

public class Bank {
    
    ArrayList<BankAccount> list = new ArrayList<>();
    
    
    // helper method to find the index of a specified account
    
        private int search(String accountNumberIn)
        {
            for(int i = 0; i <= list.size() - 1; i++)
            {
                
            BankAccount tempAccount = list.get(i); // find the account at index i
            String tempNumber = tempAccount.getAccountNumber(); // get account number
            
                if(tempNumber.equals(accountNumberIn)) // if this is the account we are looking for
                {
                return i; // return the index
                }
            }
            return -999;
        }
        
    // return the total number of items
        
        public int getTotal()
        {
        return list.size();
        }
        
    // return an account with a particular account number
        
        public BankAccount getItem(String accountNumberIn)
        {
            int index = search(accountNumberIn);
            if(index != -999) // check that account exists
            {
                return list.get(index);
            }
            else
            {
                return null; // no such account
            }
    }
        
    // add an item to the list
        
        public boolean addAccount(String accountNumberIn, String nameIn)
        {
            if(search(accountNumberIn) == -999) // check that account does not already exist
            {
                list.add(new BankAccount(accountNumberIn, nameIn)); // add new account
                return true;
            }
            return false;
        }
        
    // deposit money in a specified account
        
        public boolean depositMoney(String accountNumberIn, double amountIn)
        {
            BankAccount acc = getItem(accountNumberIn);
            if(acc != null)
            {
                acc.deposit(amountIn);
                return true; // indicate success
            }
            else
            {
                return false; // indicate failure
            }
        }
        
    // withdraw money from a specified account
        
        public boolean withdrawMoney(String accountNumberIn, double amountIn)
        {
            BankAccount acc = getItem(accountNumberIn);
            if(acc != null && acc.getBalance() >= amountIn)
            {
                acc.withdraw(amountIn);
                return true; // indicate success
            }
            else
            {
                return false; // indicate failure
            }
        }
        
    // remove an account
        
        public boolean removeAccount(String accountNumberIn)
        {
            int index = search(accountNumberIn); // find index of account
            if(index != -999) // if account exists account
            {
                list.remove(index);
                return true; // remove was successful
            }
            else
            {
                return false; // remove was unsuccessful
            }
        }
    }

最后用 main 方法测试 class：

import java.util.ArrayList;

public class BankAccountTester {
    
     public static void main(String args[])
       {
          
         Bank myBank = new Bank();   
         ArrayList<BankAccount> accountList = new ArrayList<>();
            
           
         accountList.add(new BankAccount("123","Susan Richards"));
         accountList.add(new BankAccount("44567109","Delroy Jacobs"));
         accountList.add(new BankAccount("46376205","Sumana Khan"));
            
            char choice;
           
            
           do {
             
            System.out.println("Please enter your account number:");
            String myAcc = EasyScanner.nextString();
                
            BankAccount account = myBank.getItem(myAcc);
                
            System.out.println("Please enter an amount to deposit: ");
            double depIn = EasyScanner.nextDouble();
            
            boolean found = myBank.depositMoney(myAcc, depIn);
            
            if (found) 
            {
                System.out.println("Deposit made");
                
            } else 
            {
                System.out.println("Invalid account number"); //this is running everytime
            }
            
            System.out.println("Would you like to deposit again? (y/n)");
            choice = EasyScanner.nextChar();
            
           } while (choice == 'y' || choice == 'Y');
            
          System.out.println("Account Details..... \n");
          
          for(BankAccount item : accountList)
            {
                System.out.println("Account number: " + item.getAccountNumber());
                System.out.println("Account name: " + item.getAccountName());
                System.out.println("Current balance: " + item.getBalance());
                System.out.println();
            
            }
          
       
       }  
     
     
 }

我得到的输出如下：


Please enter your account number:
123
Please enter an amount to deposit: 
10
**Invalid account number**
Would you like to deposit again? (y/n)

虽然我猜到正在搜索的ArrayList中没有包含已输入的帐户信息，但我无法弄清楚为什么没有提取帐号。

如有任何帮助，我们将不胜感激！

Answer 1

您必须在 myBank 中而不是在 main 中添加到 accountList。

     myBank.addAccount ("123","Susan Richards"));
     myBank.addAccount ("44567109","Delroy Jacobs"));
     myBank.addAccount ("46376205","Sumana Khan"));

Java: 搜索时未返回 ArrayList 项目

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