设计模式（六）建造者(创建型)

2021-11-18 20:01:44

概念

将一个复杂的构建与其表示相分离，使得同样的构建过程可以创建不同的表示。

类图

代码

public abstract class Computer {
    private String type;
    private String cpu;
    private String ram;
    private String os;
    public String getType() {
        return type;
    }
    public void setType(String type) {
        this.type = type;
    }
    public String getCpu() {
        return cpu;
    }
    public void setCpu(String cpu) {
        this.cpu = cpu;
    }
    public String getRam() {
        return ram;
    }
    public void setRam(String ram) {
        this.ram = ram;
    }
    public String getOs() {
        return os;
    }
    public void setOs(String os) {
        this.os = os;
    }
    
}

创建两种型号的计算机：

public class T410 extends Computer {
    private String hardDisk;

    public T410() {
        this.setType("ThinkPad T410i");
    }

    public String getHardDisk() {
        return hardDisk;
    }

    public void setHardDisk(String hardDisk) {
        this.hardDisk = hardDisk;
    }

    @Override
    public String toString() {
        return "T410 [hardDisk=" + hardDisk + ", getType()=" + getType()
                + ", getCpu()=" + getCpu() + ", getRam()=" + getRam()
                + ", getOs()=" + getOs() + ", getClass()=" + getClass()
                + ", hashCode()=" + hashCode() + "]";
    }
}

public class X201 extends Computer {

    public X201() {
        this.setType("Thinkpad X201i");
    }

    @Override
    public String toString() {
        return "X201 [getType()=" + getType() + ", getCpu()=" + getCpu()
                + ", getRam()=" + getRam() + ", getOs()=" + getOs()
                + ", getClass()=" + getClass() + ", hashCode()=" + hashCode()
                + "]";
    }
}

在计算机产品类的基础上增加一个ComputerBuilder接口，以及两个的实现类，以便对计算机进行生产：

public interface ComputerBuilder {
    void buildCpu();
    void buildRam();
    void buildHardDisk();
    void BuildOs();
    
    Computer getResult();
}

public class T410Builder implements ComputerBuilder {

    private T410 computer = new T410();

    @Override
    public void buildCpu() {
        computer.setCpu("i5");

    }

    @Override
    public void buildRam() {
        computer.setRam("4G");

    }

    @Override
    public void buildHardDisk() {
        computer.setHardDisk("500G");

    }

    @Override
    public void BuildOs() {
        computer.setOs("Win7");

    }

    @Override
    public Computer getResult() {
        return computer;
    }

}

public class X201Builder implements ComputerBuilder {

    private X201 computer = new X201();
    
    @Override
    public void buildCpu() {
        computer.setCpu("i7");

    }

    @Override
    public void buildRam() {
        computer.setRam("8G");

    }

    @Override
    public void buildHardDisk() {
        //没有HaedDisk

    }

    @Override
    public void BuildOs() {
        computer.setOs("Win8");

    }

    @Override
    public Computer getResult() {
        return computer;
    }

}

再鞥家导演者：

public class ComputerDirector {
    ComputerBuilder builder;
    public T410 constructT410()
    {
        builder = new T410Builder();
        builder.buildCpu();
        builder.buildHardDisk();
        builder.BuildOs();
        builder.buildRam();
        return (T410) builder.getResult();
    }
    
    public X201 constructX201()
    {
        builder = new X201Builder();
        builder.buildCpu();
        builder.buildHardDisk();
        builder.BuildOs();
        builder.buildRam();
        return (X201) builder.getResult();
    }
}

测试：

public class ComputerTest {

    public static void main(String[] args) {
        ComputerDirector director = new ComputerDirector();
        Computer t410 = director.constructT410();
        System.out.println(t410);
        System.out.println("-------------------------");
        Computer x201 = director.constructX201();
        System.out.println(x201);
    }

}

与抽象工厂的区别

在建造者模式里，有个指导者，由指导者来管理建造者，用户是与指导者联系的，指导者联系建造者最后得到产品。即建造模式可以强制实行一种分步骤进行的建造过程。

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。

本文转自我爱物联网博客园博客，原文链接：http://www.cnblogs.com/yydcdut/p/3856359.html，如需转载请自行联系原作者

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