java设计模式--建造者模式

建造模式是将复杂的内部创建封装在内部，对于外部调用的人来说，只需要传入建造者和建造工具，对于内部是如何建造成成品的，调用者无需关心。

举个例子：汽车的生产

/**
 * 构建汽车
 * @author Administrator
 *
 */
public class Car {
    //企业发动机
    private Fadongji fadongji;
    //模型
    private Moju moju;
    
    /**
     * 运行汽车
     */
    public void run(){
        System.out.println("运行汽车");
        
    }
    
    public Fadongji getFadongji() {
        return fadongji;
    }
    
    public void setFadongji(Fadongji fadongji) {
        this.fadongji = fadongji;
    }
    
    public Moju getMoju() {
        return moju;
    }
    
    public void setMoju(Moju moju) {
        this.moju = moju;
    }
}

/**
 * 发动机类
 * @author Administrator
 *
 */
class Fadongji{
    String name;
    public Fadongji(String name) {
        super();
        this.name = name;
    }
    
}

//模具
class Moju{
    String name;
    public Moju(String name) {
        super();
        this.name = name;
    }
    
}

建造者

/**
 * 建造
 * @author Administrator
 *
 */
public interface CarBuilderInstance {
    
    Fadongji buildFadongji();
    
    Moju buildMoju();
    

}

装备者

/**
 * 装配
 * @author Administrator
 *
 */
public interface CarDirectorInstance {
    
    Car  directorCar();

}

建造者的具体实现

/**
 * 一汽厂商
 * @author Administrator
 *
 */
public class YiqiBuilder implements CarBuilderInstance {

    public Fadongji buildFadongji() {
        System.out.println("一汽发动机");
        return new Fadongji("一汽发动机");
    }

    public Moju buildMoju() {
        System.out.println("一汽模具");
        return new Moju("一汽模具");
    }

}

装配者的具体实现

/**
 * 一汽装配
 * @author Administrator
 *
 */
public class YiqiDirector implements CarDirectorInstance{
    
    //需要建造者进行装配
    private CarBuilderInstance builder;

    public YiqiDirector(CarBuilderInstance builder) {
        super();
        this.builder = builder;
    }

    public Car directorCar() {
        Fadongji fadongji = builder.buildFadongji();
        Moju moju = builder.buildMoju();
        Car car = new Car();
        car.setFadongji(fadongji);
        car.setMoju(moju);
        return car;
    }

}

测试

public class Client {
    
    public static void main(String[] args) {
        
        CarDirectorInstance directorInstance = new YiqiDirector(new YiqiBuilder());
        Car car = directorInstance.directorCar();
        car.run();
        
    }

}

需要现有建造再有装配

应用例子：StringBuilder中append,  PreparedStatement