java设计模式学习

1.观察者

package designpattern;

import java.util.ArrayList;

public class Observer {

    public static void main(String[] args) {
        Button b = new Button();
        b.addActionListener(new MyactionListener());
        b.addActionListener(new MyactionListener2());
        b.btnPressed();
    }

}

class Button {
    ArrayList<ActionListener> listeners = new ArrayList<ActionListener>();
    
    public void btnPressed()
    {
        ActionEvent e = new ActionEvent(this);
        for (int i = 0; i < listeners.size(); i++) {
            listeners.get(i).actionPerform(e);
        }
    }
    
    public void addActionListener(ActionListener i){
        listeners.add(i);
    }
    
    
}

interface ActionListener{
    public void actionPerform(ActionEvent e);
}

class ActionEvent{

    private long when ;
    
    private Object source ;
    
    public ActionEvent(Object source) {
        when = System.currentTimeMillis();
    }
    
    public Object getSource() {
        return source;
    }

    public void setSource(Object source) {
        this.source = source;
    }

    public long getWhen() {
        return when;
    }

}

class MyactionListener implements ActionListener{

    @Override
    public void actionPerform(ActionEvent e) {
        p.echo("presess1");
    }
    
}

class MyactionListener2 implements ActionListener{

    @Override
    public void actionPerform(ActionEvent e) {
        p.echo("presess2");
    }
    
}

2.单例模式

package com.singleton;

import java.util.ArrayList;
import java.util.List;


//单例模式
public class Singleton {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Car2 car1 = Car2.getInstance();
        Car2 car2 = Car2.getInstance();
        
        p.echo(car1 == car2);

    }

}

class Car{
    
    //单例
    private static Car car = new Car(); 
    //多例
    private static List<Car> cars = new ArrayList<Car>();
    
    //不可以new这个类
    private void car(){}
    
    public static Car getInstance(){
        return car;
    }
}

//另一种实现方式
class Car2{
    
    private static Car2 car; 
    static{
        Car2 car = new Car2();    
    }
    //不可以new这个类
    private void Car2(){}
    
    public static Car2 getInstance(){
        return car;
    }
}

3.简单工厂

工厂模式的好处：可以有效控制对象的生产过程，如果写在构造方法里面则无法控制

　　

package com.simplefactory;


/**
 * 简单工厂 (只要是控制了对象的生产过程的都可以叫做工厂)
 * 任意定制交通工具（Moveable 限制 有多态存在）， 控制交通工具的产生过程()
 * @author root
 *
 */
public class Factory {

    public static void main(String[] args) {
        MoveFactory factory = new CarFactory();
//        MoveFactory factory = new PlanFactory();
        Moveable m = factory.create();
        m.run();

    }

}

//限制任意定制交通工具
interface Moveable{
    void run();
}

//汽车
class Car implements Moveable{

    @Override
    public void run() {
        p.echo("汽车。。。。。");
    }
    
}

class Plan implements Moveable{

    @Override
    public void run() {
        p.echo("飞机。。。。。");
        
    }
    
}

//接口比抽象类会更好，因为接口可以有多继承
interface MoveFactory{
    Moveable create();
}

/*abstract class MoveFactory{
    abstract void create();
}*/

//汽车工厂
class CarFactory implements MoveFactory{

    @Override
    public Moveable create() {
        return new Car();
        
    }
    
}

//飞机工厂
class PlanFactory implements MoveFactory{
    
    @Override
    public Moveable create() {
        return new Plan();
        
    }
    
}

 

 3.2抽象工厂

package com.abstructfactory;

/**
 * 控制一系列产品的产生(替换一系列的产品)
 * 
 * @author songjiankang
 *
 */
public class AbstructFactory {

    public static void main(String[] args) {
//        MyAbstructFactory = new DefaultFactory();
        MyAbstructFactory factory = new MagicFactory();
        factory.createVehicle().run();
        factory.createWeaWeapon().shoot();

    }

}

abstract class Vehicle{
    abstract public void run();
}

class Car extends Vehicle{

    public void run() {
        p.echo("汽车。。。");
    }
}

class Broom extends Vehicle{
    public void run() {
        p.echo("扫帚。。。");
    }
}

abstract class Weapon{
    abstract public void shoot();
}

class AK47 extends Weapon{
    public void shoot(){
        p.echo("开枪。。。");
    }
}

class Stick extends Weapon{
    public void shoot(){
        p.echo("魔棍。。。");
    }
}


abstract class MyAbstructFactory{
    abstract public Vehicle createVehicle();
    abstract public Weapon createWeaWeapon();
}


class DefaultFactory extends MyAbstructFactory{

    @Override
    public Vehicle createVehicle() {
        return new Car();
    }

    @Override
    public Weapon createWeaWeapon() {
        return new AK47();
    }
    
}


class MagicFactory extends MyAbstructFactory{

    @Override
    public Vehicle createVehicle() {
        return new Broom();
    }

    @Override
    public Weapon createWeaWeapon() {
        return new Stick();
    }
    
}

简单工厂是在产品方面进行扩展方便，但系列会很麻烦，工厂泛滥

抽象工厂在产生产品系列时方便，但产生产品品种则很麻烦

spring 的 Bean 工厂实现方式

把类名以key、value的格式存入到 xml中，然后又一个BeanFactory类读取这个文件，把读取的这个文件以key、value对应的Object格式存到一个map里， 

当获取某个id对应的Object时从map中直接得到

  抽象工厂简单示意图

 

 自定义输出类：

class p{

    public static void echo(Object o) {
        System.out.println(o);
    }
}