java 面向对象 声明 调用 使用 详解

package com.day20.test;

public class Bank {
    private Costomer[] costomers=new Costomer[10];
    private int numberCostomer;
    
    public Bank() {
        
    }
    //添加客户
    
    public void addCostomer(String f,String l) {
        Costomer cost=new Costomer(f,l);
        
        //在数组中追加
        costomers[numberCostomer]=cost;
        numberCostomer++;
    }
    
    //获取用户个数
    public int getNumCostomer() {
        return numberCostomer;
    }
    // 获取指定位置上的客户
    public Costomer getCostomer(int index) {
        //这样写不太严谨
    //    return costomers[index];
        if(index>=0 && index< numberCostomer) {
            return costomers[index];
        }
        return null;
    }

}
 

 

//账户类

package com.day20.test;

public class Account {
    //账号ID
    private int id;
    //余额
    private double balance;
    //年化率
    private double annuallneterestRate;
    
    public Account(int id,double balance,double annuallneterestRate) {
        this.id=id;
        this.balance=balance;
        this.annuallneterestRate=annuallneterestRate;
    }
    
    public int getid() {
        return id;
    }
    
    public double getbalance() {
        return balance;
    }
    
    public double getannuallneterestRate() {
        return annuallneterestRate;
    }
    
    
    public void setid(int id) {
        this.id=id;
    }
    
    public void setbalance(double balance) {
        this.balance=balance;
    }
    

    public void setannuallneterestRate(double annuallneterestRate) {
        this.annuallneterestRate=annuallneterestRate;
    }
    
    //取钱
    public void withdraw(double amount) {
        if(this.balance<amount) {
            System.out.println("余额不足");
            System.exit(0);
        }
        this.balance-=amount;
        System.out.println("成功取出"+amount);
    }
    
    //存钱
    public void deposit(double amount) {
        if(amount >0) {
            this.balance+=amount;
            System.out.println("成功存入"+amount);
        }

    }
}
 

//客户类

package com.day20.test;

public class Costomer {
    private String firstName;
    private String lastName;
    private Account account;
    public Costomer(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;
    }
    
    
    

}
 

 

//调用类

package com.day20.test;

import java.util.Arrays;

public class Test20 {
    
    public static void main(String[] args) {
        System.out.println("自学JAVA 第20天");
        //创建一个用户 然后 调用账户钱
    //    Costomer cust=new  Costomer("Json", "wl");
        //Account acct =new Account(1000, 2000, 0.0123);
        
        //把这个用户跟账户钱进行绑定
    //    cust.setAccount(acct);
        
    //    cust.getAccount().deposit(100);
    //    cust.getAccount().withdraw(960);
        //cust.getAccount().withdraw(2000);
        
        //mvc 设计模式
        // c 控制器  m 模型 v 视图 
        // import关键字的使用 
        //import java.util.Arrays;  Arrays.toString() 
    //    String info = Arrays.toString(new int[] {1,2,3});

        
        //测试银行类
        Bank bank=new Bank();
        //创建一个客户
        bank.addCostomer("json", "wl");
        //给这个客户开一个银行账号 存入钱 年化率为***
        bank.getCostomer(0).setAccount(new Account(15641, 5200, 0.1444));
        //这个客户花钱了100
        bank.getCostomer(0).getAccount().withdraw(100);
        //查询这个客户还有多少余额
        double bulance=bank.getCostomer(0).getAccount().getbalance();
        System.out.println("余额为"+bulance);
        
    }

}