设计模式之建造者模式！

建造者模式的本质

• 分离了对象子组件的单独构造（由Builder来负责）和装配（由Director负责）。从而可以构造出复杂的对象。这个模式适用于：某个对象的构建过程复杂的情况下使用。
• 由于实现了构建和装配的解耦。不同的构建器，相同的装配，也可以做出不同的对象；相同的构建器，不同的装配顺序也可以做出不同的对象。也就是实现了构建算法、装配算法的解耦，实现了更好的复用。

应用场景

• StringBuilder类中的append方法
• SQL中的PreparedStatement
• JDOM中，DomBuilder、SAXBuilder

具体代码

    package com.yishan.bulider;

    /**
    * 宇宙飞船
    * @author : yishan
    * @date : 2020-09-24 09:54
    */
    public class AirShip {
        private OrbitalModule orbitalModule; //轨道舱
        private Engine engine; //发动机
        private EscapeTower escapeTower; //逃逸塔

        public void launch(){
            System.out.println("发射！");
        }

        public OrbitalModule getOrbitalModule() {
            return orbitalModule;
        }

        public void setOrbitalModule(OrbitalModule orbitalModule) {
            this.orbitalModule = orbitalModule;
        }

        public Engine getEngine() {
            return engine;
        }

        public void setEngine(Engine engine) {
            this.engine = engine;
        }

        public EscapeTower getEscapeTower() {
            return escapeTower;
        }

        public void setEscapeTower(EscapeTower escapeTower) {
            this.escapeTower = escapeTower;
        }
    }


    class OrbitalModule{
        private String name;

        public OrbitalModule(String name) {
            this.name = name;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }
    }

    class Engine{
        private String name;

        public Engine(String name) {
            this.name = name;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }
    }

    class EscapeTower{
        private String name;

        public EscapeTower(String name) {
            this.name = name;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }
    }



    package com.yishan.bulider;

    /**
    * 构建子组件的接口
    * @author : yishan
    * @date : 2020-09-24 10:06
    */
    public interface AirShipBuilder {
        Engine builderEngine();
        OrbitalModule builderOrbitalModule();
        EscapeTower builderEscapeTower();
    }




    package com.yishan.bulider;

    /**
    * 组装飞船对象的接口
    * @author : yishan
    * @date : 2020-09-24 10:08
    */
    public interface AirShipDirector {

        /**
        * 组装飞船对象
        * @return
        */
        AirShip directAirShip();
    }




    package com.yishan.bulider;

    /**
    * 构建者的实现类
    * @author : yishan
    * @date : 2020-09-24 10:11
    */
    public class SxtAirShipBuilder implements AirShipBuilder{ 
        //StringBuilder,以后学习XML解析中，JDOM库中的类：DomBuilder,SaxBuilder
        @Override
        public Engine builderEngine() {
            System.out.println("构建发动机");
            return new Engine("新构建的发动机");
        }

        @Override
        public OrbitalModule builderOrbitalModule() {
            System.out.println("构建逃逸塔");
            return new OrbitalModule("构建好的逃逸塔");
        }

        @Override
        public EscapeTower builderEscapeTower() {
            System.out.println("构建轨道舱");
            return new EscapeTower("构建好的轨道舱");
        }
    }




    package com.yishan.bulider;

    /**
    * 装配的实现类
    * @author : yishan
    * @date : 2020-09-24 10:18
    */
    public class SxtAirshipDirector implements AirShipDirector{

        private AirShipBuilder builder;

        public SxtAirshipDirector(AirShipBuilder builder) {
            this.builder = builder;
        }

        /**
        * 装配成为飞船对象
        * @return
        */
        @Override
        public AirShip directAirShip() {
            Engine e = builder.builderEngine();
            OrbitalModule o = builder.builderOrbitalModule();
            EscapeTower et = builder.builderEscapeTower();

            AirShip ship = new AirShip();
            ship.setEngine(e);
            ship.setOrbitalModule(o);
            ship.setEscapeTower(et);

            return ship;
        }
    }




    package com.yishan.bulider;

    /**
    * @author : yishan
    * @date : 2020-09-24 10:25
    */
    public class Client {
        public static void main(String[] args) {

            AirShipDirector director = new SxtAirshipDirector(new SxtAirShipBuilder());

            AirShip ship = director.directAirShip();

            System.out.println(ship.getEngine().getName());

            ship.launch();
        }
    }

赏

谢谢你请我吃糖果