每日博客

实验 24：模板方法模式

package rjsj.no24;

 

public abstract class Operator {

    public abstract void connDB();

 

    public void openDB(){

        System.out.println("---打开数据库---");

    }

 

    public void useDB(){

        System.out.println("---使用数据库---");

    }

 

    public void closeDB(){

        System.out.println("---关闭数据库---");

    }

 

    public void display(){

        this.connDB();

        this.openDB();

        this.useDB();

        this.closeDB();

    }

}

package rjsj.no24;

 

public class Oracle extends Operator{

    @Override

    public void connDB() {

        System.out.println("连接---Oracle---数据库");

    }

}

package rjsj.no24;

 

public class SQLServer extends Operator{

    @Override

    public void connDB() {

        System.out.println("连接---SQLServer---数据库");

    }

}

package rjsj.no24;

 

public class Client {

    public static void main(String[] args) {

        Operator dbOperator;

 

        dbOperator = new SQLServer();

        dbOperator.display();

        System.out.println("————————————————————");

        dbOperator = new Oracle();

        dbOperator.display();

    }

}

 

实验 25：访问者模式

package com.gazikel;

 

public interface Product {

 

    void accept(Visitor visitor);

}

package com.gazikel;

 

public class Apple implements Product {

    @Override

    public void accept(Visitor visitor) {

        visitor.visit(this);

    }

}

package com.gazikel;

 

public class Book implements Product {

    @Override

    public void accept(Visitor visitor) {

        visitor.visit(this);

    }

}

package com.gazikel;

 

public abstract class Visitor {

    protected String name;

 

    public void setName(String name) {

        this.name = name;

    }

 

    public abstract void visit(Apple apple);

 

    public abstract void visit(Book book);

}

package com.gazikel;

 

public class Customer extends Visitor {

    @Override

    public void visit(Apple apple) {

        System.out.println("顾客" + name + "选苹果");

    }

 

    @Override

    public void visit(Book book) {

        System.out.println("顾客" + name + "买书");

    }

}

package com.gazikel;

 

public class Packer extends Visitor {

    @Override

    public void visit(Apple apple) {

        System.out.println("打包员" + name + "给苹果打包");

    }

 

    @Override

    public void visit(Book book) {

        System.out.println("打包员" + name + "给书打包");

    }

}

package com.gazikel;

 

public class Saler extends Visitor {

    @Override

    public void visit(Apple apple) {

        System.out.println("收银员" + name + "给苹果过秤，然后计算其价格");

    }

 

    @Override

    public void visit(Book book) {

        System.out.println("收银员" + name + "直接计算书的价格");

 

    }

}

package com.gazikel;

 

import java.util.ArrayList;

import java.util.List;

 

public class BuyBasket {

 

    private List<Product> products = new ArrayList();

 

    public void accept(Visitor visitor) {

        for (Product product : products) {

            product.accept(visitor);

        }

    }

 

    public void addProduct(Product p) {

        products.add(p);

    }

 

    public void removeProduct(Product p) {

        products.remove(p);

    }

}

package com.gazikel;

 

public class Client {

 

    public static void main(String[] args) {

        BuyBasket buyBasket = new BuyBasket();

 

        buyBasket.addProduct(new Apple());

        buyBasket.addProduct(new Book());

 

        Visitor saler = new Saler();

        saler.setName("李华");

        System.out.println("----收银员----");

        buyBasket.accept(saler);

 

        Visitor packer = new Packer();

        packer.setName("赵强");

        System.out.println("----打包员----");

        buyBasket.accept(packer);

 

        Visitor customer = new Customer();

        customer.setName("王超");

        System.out.println("----顾客----");

        buyBasket.accept(customer);

    }

}