java

　银行功能实现，主要为抽象类及接口的运用

package com.javatest.bankimple;
/* UnionPay */
//银联接口
public interface UnionPay {
    public static final double EXCHANGERATE = 6.13;  //汇率
    public abstract void save(); //存钱
    double pick(double pick);   //取钱
    void check();  //查询余额
    boolean checkPassWord(int password);  //验证密码
}

interface ICBC extends UnionPay{  //工商行接口
    public abstract void onlineCharge();  //在线支付
}

interface ABC extends UnionPay{  //农行接口
    public abstract void onlineChargeForMobile();  //在线支付电话费
}

package com.javatest.bankimple;
import com.javatest.bankimple.*;

/* 工商行及农行的接口实现 */

//实现工商行接口
public class ICBCImple implements ICBC{
    private double currentSum;  //卡上目前余额,钱的来源就是要存储、读取记录的地方
    private int passwordPerson;
    ICBCImple(double currentSum,int passwordPerson){
        this.currentSum = currentSum;
        this.passwordPerson = passwordPerson;
    }
    
    /*
     * 存钱
     * */
    public void save(){}
     
    /*
     * 取钱
     * */
    public double pick(double pickNum){ 
        
        //核查是否可取款
        if(pickNum<=currentSum){  
            currentSum -= pickNum;//卡上余额
                System.out.println("取款成功，余额为："+currentSum);
        }else{
            System.out.println("卡上余额不足");
        }
        return currentSum;
    } 
    
    /*
     * 查询余额
     * */
    public void check(){
        System.out.println("卡上余额为："+currentSum);
    }  
    
    /*
     * 验证密码
     * */
    public boolean checkPassWord(int passwordICBC){
        boolean flag;
        if(passwordICBC == passwordPerson){
            System.out.println("输入正确");
            flag = true;
        }else{
            System.out.println("输入错误");
            flag = false;
        }
        return flag;        
    }
    
    /*
     * 在线支付
     * */
    public void onlineCharge(){}
}


//农行接口
class ABCImple implements ABC{
    boolean flag;
    
    public void save(){} //存
    public double pick(double pickNum){
        return 0;
    }   //取钱
    public void check(){
    }  //查钱
    public boolean checkPassWord(int passwordABC){
        return flag;
    }  //验证密码
    public void onlineChargeForMobile(){}  //在线支付电话费
}

package com.javatest.bankimple;
import com.javatest.bankimple.UnionPay;
import com.javatest.bankimple.ICBCImple;
import java.util.Scanner;

/* main测试 */

public class BankImple {
    public static void main(String[] args){         
        UnionPay icbc = new ICBCImple(50000,123);//建工商行--向上造型
        
        //实现工商行功能
        System.out.println("工商银行欢迎你");
        Scanner scanICBC = new Scanner(System.in);
        
        /*
         * 验证密码
         * */
        System.out.print("输入密码：");
        int password = scanICBC.nextInt();
        
        if(icbc.checkPassWord(password)){                
        /*
         * 查询余额
         * */
            System.out.println("是否要查询余额(Y/N)：");
            String inputRemain = scanICBC.next();
            if(inputRemain.equals("Y")){
                icbc.check();
                }else if(inputRemain.equals("N")){
                    System.out.println("不查询余额");
                }
                
        /*
         * 取钱
         * */
            System.out.print("请输入取款数目：");
            double pickICBC = scanICBC.nextDouble();
            icbc.pick(pickICBC);
            }
            else{
                System.out.println("密码错误，无权访问");
            }
        }
}

其中，类成员变量私有、对应方法公开以供外部访问/调用的用法 --供外部访问，但不允许外部修改

public class ICBCImple implements ICBC{
    private double money;   //卡上余额
    private int pwd;  //密码
    ICBCImple(double money,int pwd){
        this.money = money;
        this.pwd = pwd;
    }
....
}