GOF23设计模式之:建造者模式
场景
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我们要建造一个复杂的产品.比如:神州飞船,iphone.这个复杂的产品的创建.有这样一个问题需要处理
- 装配这些子组件是不是有个步骤问题?
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实际开发中,我们所需要的对象构建时,也非常复杂,有很多步骤需要处理时
建造模式的本质
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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
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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
public class AirShip {
private OrbitalModule orbitalModule; //轨道舱
private Engine engine; //发动机
private EscapeTower escapeTower; //逃逸塔
public OrbitalModule getOrbitalModule() {
return orbitalModule;
}
public void Launch(){
System.out.println("发射!");
}
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() {
}
public OrbitalModule(String name) {
super();
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
class Engine{
private String name;
public Engine() {
}
public Engine(String name) {
super();
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
class EscapeTower{
private String name;
public EscapeTower() {
super();
}
public EscapeTower(String name) {
super();
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
public interface AirShipBuilder {
Engine buildEngine();
OrbitalModule buildOrbitalModule();
EscapeTower buildEscapeTower();
}
public class LorindaArishipBuilder implements AirShipBuilder{
@Override
public Engine buildEngine() {
System.out.println("构建发动机!");
return new Engine("Lorinda发动机");
}
@Override
public OrbitalModule buildOrbitalModule() {
System.out.println("构建轨道舱!");
return new OrbitalModule("Lorinda轨道舱");
}
@Override
public EscapeTower buildEscapeTower() {
System.out.println("构建逃逸塔!");
return new EscapeTower("Lorinda逃逸塔");
}
}
public interface AirShipDirector {
AirShip createAirShip();
}
public class LorindaAirShipDirector implements AirShipDirector{
private AirShipBuilder builder;
public LorindaAirShipDirector(AirShipBuilder builder) {
super();
this.builder = builder;
}
@Override
public AirShip createAirShip() {
Engine engine = builder.buildEngine();
OrbitalModule module = builder.buildOrbitalModule();
EscapeTower tower = builder.buildEscapeTower();
AirShip ship = new AirShip();
ship.setEngine(engine);
ship.setEscapeTower(tower);
ship.setOrbitalModule(module);
return ship;
}
}
public class Client {
public static void main(String[] args) {
AirShipDirector director = new LorindaAirShipDirector(new LorindaArishipBuilder());
AirShip ship = director.createAirShip();
System.out.println(ship.getEngine().getName());
ship.Launch();
}
}
开发中的应用场景
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StringBuilder类的append方法
-
SQL中的PreparedStatement
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JDOM中,DOMBuilder,SAXBuilder