공장 모드 & 단일 모드

package com.factory;/*
 *@author:
 *@time
 */

import com.entity.Aodi;
import com.entity.Byd;
import com.entity.Car;

public class CarFactory {
    public Car getCar(String type){
        if("  ".equals(type)){
            return Aodi.getInstance();
        }
        else if("   ".equals(type)){
            return Byd.getInstance();
        }
        else
            return null;
    }
}

public static void main(String[] args) {
        Car car=new CarFactory().getCar("   ");
        car.run();
    }

    /**
     *       ，       ，        
     */

    public static void test2(){
        Car car1=new BydFactory().getCar();
        Car car2=new BaomaFactory().getCar();
        Car car3=new AodiFactory().getCar();
        car1.run();
        car2.run();
        car3.run();
    }

    //                     ，             ，        
    import com.entity.Aodi;
    import com.entity.Car;

    public class AodiFactory {

        public Car getCar(){
            return Aodi.getInstance();
        }
    }

package com.entity;/*
 *@author:
 *@time
 */

public class Baoma implements Car{

    private Baoma(){}

    /**
     *        
     */
    private static final Baoma instance=new Baoma();;
    
    public static Baoma getInstance(){
        return instance;
    }

    @Override
    public void run() {
        System.out.println("     ！");
    }

    @Override
    public void stop() {
        System.out.println("     ！");
    }
}

package com.entity;/*
 *@author:
 *@time
 */

public class Aodi implements Car{
    /**
     *           
    */
    private static volatile Aodi instance;
    private Aodi(){}
    public static Aodi getInstance(){
        if(instance==null){
            synchronized (Aodi.class){
                if(instance==null){
                    instance=new Aodi();
                    return instance;
                }
            }
        }
        return instance;
    }
    @Override
    public void run() {
        System.out.println("     ！");
    }

    @Override
    public void stop() {
        System.out.println("     ！");

    }
}

package com.entity;/*
 *@author:
 *@time
 */

public class Byd implements Car {

    /**
     *            
     */
    private static class bydClass{
        private static Byd byd=new Byd();
    }


    public static Byd getInstance(){

        return bydClass.byd;
    }
    private Byd(){}
    @Override
    public void run() {
        System.out.println("      ！");
    }

    @Override
    public void stop() {
        System.out.println("      ！");

    }
}