Java大一实训银行项目

各位朋友看看这个报错是啥原因，研究了半天没研究明白

img

TestBanking51

package banking51;


public class TestBanking51 {

  public static void main(String[] args) {
    Bank     bank = new Bank();
    Customer customer;

    // Create several customers and their accounts
    bank.addCustomers("Jane", "Simms");
    customer = bank.getCustomer(0);
    Customer.addAccount(new SavingAccount(500.00, 0.05));
    Customer.addAccount(new CheckingAccount(200.00, 400.00));
    bank.addCustomers("Owen", "Bryant");
    customer = bank.getCustomer(1);
    Customer.addAccount(new CheckingAccount(200.00));

    bank.addCustomers("Tim", "Soley");
    customer = bank.getCustomer(2);
    Customer.addAccount(new SavingAccount(1500.00, 0.05));
    Customer.addAccount(new CheckingAccount(200.00));

    bank.addCustomers("Maria", "Soley");
    customer = bank.getCustomer(3);
    // Maria and Tim have a shared checking account
    Customer.addAccount(bank.getCustomer(2).getAccount(1));
    Customer.addAccount(new SavingAccount(150.00, 0.05));

    // Generate a report
    System.out.println("\t\t\tCUSTOMERS REPORT");
    System.out.println("\t\t\t================");

    for ( int cust_idx = 0; cust_idx < bank.getNumberOFCustomers(); cust_idx++ ) {
      customer = bank.getCustomer(cust_idx);

      System.out.println();
      System.out.println("Customer: "
             + customer.getLastName() + ", "
             + customer.getFirstName());

      for ( int acct_idx = 0; acct_idx < customer.getNumberofAccounts(); acct_idx++ ) {
    Account account = customer.getAccount(acct_idx);
    String  account_type = "";

    // Determine the account type
    /* Step 1:
    **** Use the instanceof operator to test what type of account
    **** we have and set account_type to an appropriate value, such
    **** as "Savings Account" or "Checking Account".
    ***/
    if (account instanceof SavingAccount){
        account_type = "Savings Account";
    }else if (account instanceof CheckingAccount){
        account_type = "Checking Account";
    }

    // Print the current balance of the account
    /* Step 2:
    **** Print out the type of account and the balance.
    **** Feel free to use the currency_format formatter
    **** to generate a "currency string" for the balance.
    ***/
    System.out.println(account_type+":current balance is ¥ " + account.getBalance());
      }
    }
  }
}

Customer

package banking51;

//创建kehu类
public class Customer {
//     声明三个私有对象属性：firstName、lastName 和 account。
    private String firstName;
    private String lastName;
    private static Account  [] accounts;
    private static int numberofAccounts;
//     声明一个公有构造器，这个构造器带有两个代表对象属性的参数（f 和 l）
    public Customer(String f, String l){
        firstName = f;
        lastName = l;

        accounts = new Account[2];
    }
//     声明两个公有存取器来访问该对象属性，方法 getFirstName 和 getLastName
//    返
//    回相应的属性。

    public String getFirstName() {
        return firstName;
    }

    public String getLastName() {
        return lastName;
    }
    //     声明 setAccount 方法来对 account 属性赋值。

    public static void addAccount(Account account) {
       accounts[numberofAccounts++] = account;
    }

//     声明 getAccount 方法以获取 account 属性。

    public Account getAccount(int index) {
        return accounts[index];
    }
    public int getNumberofAccounts(){
        return numberofAccounts;
    }
}

31行这里数组越界了吧 ，实例化对象的时候创建的是2个长度的，超过两个就报错了吧

img

我理解你程序的大概意思是一个客户可以有两个银行账户是吗？如果是的话，有这么几个问题。第一，你的customer类中定义了account数组是static属性，属于类，不是属于该类的每个对象，也就是说该类的所有对象公有这个属性，你调用AddAccount方法的时候，是使用类名调用类方法的，每次调用你的numberofaccounts都会自增一，而你的这个accounts数组长度为2，所以当你调用三次及以上的时候，数组下标就会超过1，造成数组越界，也就是你截的图，arrayindexoutofbounds就是数组越界异常的意思。如果你想实现每个客户可以有两个银行账户的话，可以将accounts数组改为普通成员变量，addaccount方法改为普通成员方法，希望对你有所帮助，有帮助的话采纳一下吧，也可以私信讨论哦

img