设计模式（六）建造者(创建型)
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
