【Java基础 项目实例 -- Bank项目2】Account 和 customer 对象

总结:
customer.setAccount(account);   //引用,日后的account 和 customer.getAccount()的结果始终一致

实验目的

扩展银行项目，添加一个 Customer 类。Customer 类将包含一个 Account对 象。 
 
 
实验目的： 
 使用引用类型的成员变量。 
 
 提 示： 
 1. 在banking包下的创建Customer类。该类必须实现上面的UML图表中的模 型。 
 
a. 声明三个私有对象属性：firstName、lastName 和 account。  
 b. 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）  
 c. 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。   d. 声明 setAccount 方法来对 account 属性赋值。  
 e. 声明 getAccount 方法以获取 account 属性。  
 
2. 在 exercise2 主目录里，编译运行这个 TestBanking 程序。应该看到如下 输出结果:   Creating the customer Jane Smith.  Creating her account with a 500.00 balance.  Withdraw 150.00  Deposit 22.50  Withdraw 47.62  Customer [Smith, Jane] has a balance of 324.88 

UML 结构图

工程组织结构:

代码编程:

1/Account.java

package Banking_2;

public class Account {
    private double balance;//余额  ,uml前该变量是 '-'
    public Account(double init_balance){
        balance=init_balance;
    }
    public double getBalance() {
        return balance;
    }
    //存钱
    public void deposit(double amt){
        this.balance+=amt;
    }
    //取钱
    public void withdraw(double amt){
        this.balance-=amt;
    }

}

2/Customer.java

package Banking_2;

public class Customer {
    private String firstName;
    private String lastName;
    private  Account account;
    public Customer(String f,String l){
        this.firstName=f;
        this.lastName=l;
    }
    public String getFirstName() {
        return firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public Account getAccount() {
        return account;
    }
    public void setAccount(Account account) {
        this.account = account;
    }
}

3/新开一个package, 添加测试文件:TestBanking2.java

package TestBanks;
import Banking_2.*;

public class TestBanking2{
    public static void main(String[] args) {
        Customer customer=new Customer("Jane","Smith");
        Account  account=new Account(500);

        // Create an account that can has a 500.00 balance.

        System.out.println ("Creating the customer Jane Smith.");
        System.out.println("Creating her account with a 500.00 balance.");
        customer.setAccount(account);
        //code
        System.out.println("Withdraw 150.00");
        customer.getAccount().withdraw(150);
        //code
        System.out.println("Deposit 22.50");
        customer.getAccount().deposit(22.5);
        //code
        System.out.println("Withdraw 47.62");
        customer.getAccount().withdraw(47.62);
        //code
        // Print out the final account balance
        System.out.println("Customer [" + customer.getLastName()
                + ", " + customer.getFirstName()
                + "] has a balance of " + account.getBalance());
        //等价于下面的写法
        /*
         System.out.println("Customer [" + customer.getLastName()
                + ", " + customer.getFirstName()
                + "] has a balance of " + customer.getAccount().getBalance());

         */
    }
}

运行结果: