创建者模式Builder
创建者模式:
分离对象子组件的单独构造(由Builder来负责)和装配(由Director负责),对象的构造比较复杂时使用 该模式。
类图:
Builder 抽象建造者接口,规范各个组成部分的构建。
ConcreteBuilder 具体建造者角色,实现组成部分的构建,并提供示例。
Product 产品角色,创建返回的对象。
Director 导演者角色,负责创建以及使用。
优点:
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成不同的对象,相同的构建器,不同的装配顺序也可以生产成不同的对象。也就是实现了构造算法和装配算法的解耦,实现了更好的复用。
应用场景:
StringBuilder类的append方法。
SQL中的PreparedStatement
JDOM中,DomBuilder SAXBuilder
创建者模式Demo
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 package builder.domain; 2 3 /** 4 * 宇宙飞船 5 * 6 */ 7 public class AirShip { 8 private OrbitalModule orbitalModule; //轨道舱 9 private Engine engine; //发动机 10 private EscapeTower escapeTower; //逃逸塔 11 12 13 public void launch(){ 14 System.out.println("发射!"); 15 } 16 17 18 public OrbitalModule getOrbitalModule() { 19 return orbitalModule; 20 } 21 22 23 public void setOrbitalModule(OrbitalModule orbitalModule) { 24 this.orbitalModule = orbitalModule; 25 } 26 27 28 public Engine getEngine() { 29 return engine; 30 } 31 32 33 public void setEngine(Engine engine) { 34 this.engine = engine; 35 } 36 37 38 public EscapeTower getEscapeTower() { 39 return escapeTower; 40 } 41 42 43 public void setEscapeTower(EscapeTower escapeTower) { 44 this.escapeTower = escapeTower; 45 } 46 } 47 48 49 package builder.domain; 50 51 public class Engine { 52 private String name; 53 54 public Engine(String name) { 55 this.name = name; 56 } 57 58 public String getName() { 59 return name; 60 } 61 62 public void setName(String name) { 63 this.name = name; 64 } 65 } 66 67 68 package builder.domain; 69 70 public class EscapeTower { 71 private String name; 72 73 public String getName() { 74 return name; 75 } 76 77 public void setName(String name) { 78 this.name = name; 79 } 80 81 public EscapeTower(String name) { 82 super(); 83 this.name = name; 84 } 85 } 86 87 88 package builder.domain; 89 90 public class OrbitalModule { 91 private String name; 92 93 public OrbitalModule(String name) 94 { 95 this.name = name; 96 } 97 98 public String getName() { 99 return name; 100 } 101 102 public void setName(String name) { 103 this.name = name; 104 } 105 106 107 } 108 109 110 package builder.service; 111 112 import builder.domain.Engine; 113 import builder.domain.EscapeTower; 114 import builder.domain.OrbitalModule; 115 116 public interface IAirShipBuilder { 117 Engine builderEngine(); 118 OrbitalModule builderOrbitalModule(); 119 EscapeTower builderEscapeTower(); 120 } 121 122 123 package builder.service; 124 125 import builder.domain.Engine; 126 import builder.domain.EscapeTower; 127 import builder.domain.OrbitalModule; 128 129 public class AirShipBuilderImpl implements IAirShipBuilder { 130 //StringBuilder, 以后学习XML解析中,JDOM库中的类:DomBuilder,SaxBuilder 131 @Override 132 public Engine builderEngine() { 133 // TODO Auto-generated method stub 134 System.out.println("构建发动机!"); 135 return new Engine("发动机!"); 136 } 137 138 @Override 139 public OrbitalModule builderOrbitalModule() { 140 // TODO Auto-generated method stub 141 System.out.println("构建轨道舱"); 142 return new OrbitalModule("轨道舱"); 143 } 144 145 @Override 146 public EscapeTower builderEscapeTower() { 147 // TODO Auto-generated method stub 148 System.out.println("构建逃逸塔"); 149 return new EscapeTower("逃逸塔"); 150 } 151 152 } 153 154 155 package builder; 156 157 import builder.domain.AirShip; 158 159 public interface IAirShipDirector { 160 /** 161 * 组装飞船对象 162 * @return 163 */ 164 AirShip directAirShip(); 165 } 166 167 168 package builder; 169 170 import builder.domain.AirShip; 171 import builder.domain.Engine; 172 import builder.domain.EscapeTower; 173 import builder.domain.OrbitalModule; 174 import builder.service.IAirShipBuilder; 175 176 public class AirshipDirectorImpl implements IAirShipDirector { 177 private IAirShipBuilder builder; 178 179 public AirshipDirectorImpl(IAirShipBuilder builder) { 180 this.builder = builder; 181 } 182 183 @Override 184 public AirShip directAirShip() { 185 // TODO Auto-generated method stub 186 Engine e = builder.builderEngine(); 187 OrbitalModule o = builder.builderOrbitalModule(); 188 EscapeTower et = builder.builderEscapeTower(); 189 190 //装配成飞船对象 191 AirShip ship = new AirShip(); 192 ship.setEngine(e); 193 ship.setEscapeTower(et); 194 ship.setOrbitalModule(o); 195 196 return ship; 197 } 198 199 } 200 201 package builder; 202 203 import builder.domain.AirShip; 204 import builder.service.AirShipBuilderImpl; 205 206 public class Client { 207 208 public static void main(String[] args) { 209 // TODO Auto-generated method stub 210 IAirShipDirector director = new AirshipDirectorImpl(new AirShipBuilderImpl()); 211 212 AirShip ship = director.directAirShip(); 213 214 System.out.println(ship.getEngine().getName()); 215 216 ship.launch(); 217 } 218 219 }
posted on 2015-11-05 21:35 ilinux_one 阅读(263) 评论(0) 编辑 收藏 举报