java 各种设计模式学习

单例模式

实现要点

* 声明为private来隐藏构造器
* private static Singleton实例
* 声明为public来暴露实例获取方法

单例模式主要追求三个方面性能

* 线程安全
* 调用效率高
* 延迟加载

public class Singleton {
    private static volatile Singleton instance;
    private Singleton() {
    };
    public static Singleton getInstance() {
        if (instance == null) {
            synchronized (Singleton.class) {
                if (instance == null) {
                    instance = new Singleton();
                }
            }
        }
        return instance;
    }
}  

工厂模式

工厂模式主要是为创建对象提供过渡接口，以便将创建对象的具体过程屏蔽隔离起来，达到提高灵活性的目的。

//抽象产品角色
public interface Moveable {
    void run();
}
//具体产品角色
public class Plane implements Moveable {
    @Override
    public void run() {
        System.out.println("plane....");
    }
}

public class Broom implements Moveable {
    @Override
    public void run() {
        System.out.println("broom.....");
    }
}

//抽象工厂
public abstract class VehicleFactory {
    abstract Moveable create();
}
//具体工厂
public class PlaneFactory extends VehicleFactory{
    public Moveable create() {
        return new Plane();
    }
}
public class BroomFactory extends VehicleFactory{
    public Moveable create() {
        return new Broom();
    }
}
//测试类
public class Test {
    public static void main(String[] args) {
        VehicleFactory factory = new BroomFactory();
        Moveable m = factory.create();
        m.run();
    }
}

1.命令模式

package com.controller;

/**
 * @author:
 * @TODO:命令模式
 */
public class CommandTest {
	public static void main(String[] args) {
		Tv myTv = new Tv();
		CommandOn on = new CommandOn(myTv);
		CommandOff off = new CommandOff(myTv);
		CommandChange channel = new CommandChange(myTv, 2);
		Control control = new Control(on, off, channel);
		control.turnOn();
		control.changeChannel();
		control.turnOff();
	}
}
/**
 * @author:
 * @TODO:命令借口
 */
interface Command {
	void execute();
}

class Tv {
	public int currentChannel = 0;

	public void turnOn() {
		System.out.println("The televisino is on.");
	}

	public void turnOff() {
		System.out.println("The television is off.");
	}

	public void changeChannel(int channel) {
		this.currentChannel = channel;
		System.out.println("Now TV channel is " + channel);
	}
}

// 开机命令ConcreteCommand
class CommandOn implements Command {
	private Tv myTv;

	public CommandOn(Tv tv) {
		myTv = tv;
	}

	public void execute() {
		myTv.turnOn();
	}
}

// 关机命令ConcreteCommand
class CommandOff implements Command {
	private Tv myTv;

	public CommandOff(Tv tv) {
		myTv = tv;
	}

	public void execute() {
		myTv.turnOff();
	}
}

// 频道切换命令ConcreteCommand
class CommandChange implements Command {
	private Tv myTv;

	private int channel;

	public CommandChange(Tv tv, int channel) {
		myTv = tv;
		this.channel = channel;
	}

	public void execute() {
		myTv.changeChannel(channel);
	}
}

// 可以看作是遥控器Invoker
class Control {
	private Command onCommand, offCommand, changeChannel;

	public Control(Command on, Command off, Command channel) {
		onCommand = on;
		offCommand = off;
		changeChannel = channel;
	}
	
	public void turnOn() {
		onCommand.execute();
	}

	public void turnOff() {
		offCommand.execute();
	}
	
	public void changeChannel() {
		changeChannel.execute();
	}
}

转自：http://blog.csdn.net/jason0539/article/details/45110355

2.组合模式

package com.controller;

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

public class ComponentTest {

	public abstract class Component {
		String name;

		public abstract void add(Component c);

		public abstract void remove(Component c);

		public abstract void eachChild();
	}

	// 组合部件类
	public class Leaf extends Component {

		// 叶子节点不具备添加的能力，所以不实现
		@Override
		public void add(Component c) {
			System.out.println("");
		}

		// 叶子节点不具备添加的能力必然也不能删除
		@Override
		public void remove(Component c) {
			System.out.println("");
		}

		// 叶子节点没有子节点所以显示自己的执行结果
		@Override
		public void eachChild() {
			System.out.println(name + "执行了");
		}

	}

	// 组合类
	public class Composite extends Component {

		// 用来保存节点的子节点
		List<Component> list = new ArrayList<Component>();

		// 添加节点 添加部件
		@Override
		public void add(Component c) {
			list.add(c);
		}

		// 删除节点 删除部件
		@Override
		public void remove(Component c) {
			list.remove(c);
		}

		// 遍历子节点
		@Override
		public void eachChild() {
			System.out.println(name + "执行了");
			for (Component c : list) {
				c.eachChild();
			}
		}
	}

	public static void main(String[] args) {
		ComponentTest demo = new ComponentTest();
		// 构造根节点
		Composite rootComposite = demo.new Composite();
		rootComposite.name = "根节点";

		// 左节点
		Composite compositeLeft = demo.new Composite();
		compositeLeft.name = "左节点";

		// 构建右节点，添加两个叶子几点，也就是子部件
		Composite compositeRight = demo.new Composite();
		compositeRight.name = "右节点";
		Leaf leaf1 = demo.new Leaf();
		leaf1.name = "右-子节点1";
		Leaf leaf2 = demo.new Leaf();
		leaf2.name = "右-子节点2";
		compositeRight.add(leaf1);
		compositeRight.add(leaf2);

		// 左右节点加入 根节点
		rootComposite.add(compositeRight);
		rootComposite.add(compositeLeft);
		// 遍历组合部件
		rootComposite.eachChild();
	}
}

转自：http://blog.csdn.net/jason0539/article/details/22642281

3.装饰模式

package com.controller;

//定义公共接口
interface Human {
	public void wearClothes();

	public void walkToWhere();
}

// 定义装饰者
abstract class Decorator implements Human {
	private Human human;

	public Decorator(Human human) {
		this.human = human;
	}

	public void wearClothes() {
		human.wearClothes();
	}

	public void walkToWhere() {
		human.walkToWhere();
	}
}

// 下面定义三种装饰，这是第一个，第二个第三个功能依次细化，即装饰者的功能越来越多
class Decorator_zero extends Decorator {

	public Decorator_zero(Human human) {
		super(human);
	}

	public void goHome() {
		System.out.println("进房子。。");
	}

	public void findMap() {
		System.out.println("书房找找Map。。");
	}

	@Override
	public void wearClothes() {
		super.wearClothes();
		goHome();
	}

	@Override
	public void walkToWhere() {
		super.walkToWhere();
		findMap();
	}
}

// 定义被装饰者，被装饰者初始状态有些自己的装饰
class Person implements Human {

	@Override
	public void wearClothes() {
		System.out.println("穿什么呢。。");
	}

	@Override
	public void walkToWhere() {
		System.out.println("去哪里呢。。");
	}
}

// 测试类，看一下你就会发现，跟java的I/O操作有多么相似
public class DecoratorTest {
	public static void main(String[] args) {
		Human person = new Person();
		Decorator decorator = new Decorator_zero(person);
		decorator.wearClothes();
		decorator.walkToWhere();
	}
}

转自：http://blog.csdn.net/jason0539/article/details/22713711

4.原型模式

package com.controller;

import net.sf.cglib.beans.BeanCopier;

/**
 * @author:
 * @TODO:原型模式
 */
public class PrototypeTest extends Prototype{
	public static void main(String[] args)  {
		BO bo = new BO();
		bo.setAge(27);
		CloneClass cp = new CloneClass("lau",bo);
		CloneClass clonecp = null ;
		CloneClass beanCopy = new CloneClass() ;
		try {
			clonecp = (CloneClass)cp.clone();
		} catch (CloneNotSupportedException e) {
			e.printStackTrace();
		}
        clonecp.doIt();
        BeanCopier bc = BeanCopier.create(CloneClass.class, CloneClass.class, false);
        bc.copy(cp, beanCopy, null);
        beanCopy.doIt();
	}
}
/**
 * @author:
 * @TODO:克隆类  
 */
class Prototype implements Cloneable{
	@Override
	public Object clone() throws CloneNotSupportedException {
		Prototype prototype = null;    
        try{    
            prototype = (Prototype)super.clone();    
        }catch(CloneNotSupportedException e){    
            e.printStackTrace();
        }
        return prototype;
	}
}
class CloneClass extends Prototype {
	private String name ;
	private BO bo ;
	
	public CloneClass(){
	}
	public CloneClass(String name,BO bo){
		this.name = name ;
		this.bo = bo ;
	}

	public BO getBo() {
		return bo;
	}
	public void setBo(BO bo) {
		this.bo = bo;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public void doIt(){
		System.out.println(name+" I am "+bo.getAge());
	}
}

class BO{
	private int age ;
	
	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}
}

转自：http://blog.csdn.net/jason0539/article/details/23158081

5.代理模式

package com.controller;

/**
 * @author:
 * @TODO:代理模式
 */
public class ProxyTest {
	public static void main(String[] args) {
		People people_1 = new People();
		people_1.setCash(60000);
		people_1.setUsername("jeck");

		People people_2 = new People();
		people_2.setCash(40000);
		people_2.setUsername("rose");

		People people_3 = new People();

		people_3.setCash(0);
		people_3.setUsername("tom");
		people_3.setVip("vip");

		ProxyClass proxy_buy = new ProxyClass();
		proxy_buy.setPeople(people_1);
		proxy_buy.buy_mycar();

		proxy_buy.setPeople(people_2);
		proxy_buy.buy_mycar();

		proxy_buy.setPeople(people_3);
		proxy_buy.buy_mycar();
	}
}

interface CarShop {
	public void buy_mycar();
}

class People implements CarShop {

	private int cash;
	private String vip;
	private String username;

	@Override
	public void buy_mycar() {
		System.out.print(username + "是vip 客户，可以直接购买新车！");
	}

	public int getCash() {
		return cash;
	}

	public void setCash(int cash) {
		this.cash = cash;
	}

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getVip() {
		return vip;
	}

	public void setVip(String vip) {
		this.vip = vip;
	}
}

class ProxyClass implements CarShop {

	private People people;

	public People getPeople() {
		return people;
	}

	public void setPeople(People people) {
		this.people = people;
	}

	@Override
	public void buy_mycar() {

		if (people.getVip() == "vip") {
			people.buy_mycar();
			return;
		}
		if (people.getCash() >= 50000) {
			System.out.println(people.getUsername() + " 买了新车，交易结束！");
		} else {
			System.out.println(people.getUsername() + " 钱不够，不能买车，继续比赛！");
		}
	}
}

转自：http://blog.csdn.net/jason0539/article/details/22974405

6.策略模式

package com.controller;

/**
 * @author:
 * @TODO:策略模式
 */
public class StrategyTest {

	public static void main(String[] args) {

		Context context;
		System.out.println("----------刚到吴国使用第一个锦囊---------------");
		context = new Context(new BackDoor());
		context.operate();
		System.out.println("\n");

		System.out.println("----------刘备乐不思蜀使用第二个锦囊---------------");
		context.setStrategy(new GivenGreenLight());
		context.operate();
		System.out.println("\n");

		System.out.println("----------孙权的追兵来了，使用第三个锦囊---------------");
		context.setStrategy(new BlackEnemy());
		context.operate();
		System.out.println("\n");
	}
}

/**
 * @author:
 * @TODO:策略接口
 */
interface IStrategy {
	public void operate();
}

class BackDoor implements IStrategy {
	@Override
	public void operate() {
		System.out.println("找乔国老帮忙，让吴国太给孙权施加压力，使孙权不能杀刘备");
	}
}

class GivenGreenLight implements IStrategy {
	@Override
	public void operate() {
		System.out.println("求吴国太开个绿灯，放行");
	}
}

class BlackEnemy implements IStrategy {
	@Override
	public void operate() {
		System.out.println("孙夫人断后，挡住追兵");
	}
}

class Context {
	private IStrategy strategy;

	// 构造函数，要你使用哪个妙计
	public Context(IStrategy strategy) {
		this.strategy = strategy;
	}

	public void setStrategy(IStrategy strategy) {
		this.strategy = strategy;
	}

	public void operate() {
		this.strategy.operate();
	}
}

转自：http://blog.csdn.net/jason0539/article/details/45007553