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java设计模式：工厂方法 + 建造者模式

news 2025/9/29 5:48:46

模式结合设计方案

这个设计充分利用了两种模式的优势：工厂方法负责创建不同类型产品的建造者，而建造者模式负责分步骤构造复杂产品
。
类结构设计

- Computer (产品)
- ComputerBuilder (抽象建造者) 
- GamingComputerBuilder, OfficeComputerBuilder (具体建造者)
- ComputerBuilderFactory (建造者工厂)
- ComputerDirector (指挥者)

💻 完整代码实现

产品类 - Computer

public class Computer {private String cpu;private String memory;private String storage;private String graphicsCard;private String powerSupply;// 私有构造函数，只能通过建造者构建private Computer() {}// Setter方法public void setCpu(String cpu) { this.cpu = cpu; }public void setMemory(String memory) { this.memory = memory; }public void setStorage(String storage) { this.storage = storage; }public void setGraphicsCard(String graphicsCard) { this.graphicsCard = graphicsCard; }public void setPowerSupply(String powerSupply) { this.powerSupply = powerSupply; }@Overridepublic String toString() {return String.format("Computer[CPU=%s, Memory=%s, Storage=%s, Graphics=%s, Power=%s]", cpu, memory, storage, graphicsCard, powerSupply);}
}

抽象建造者 - ComputerBuilder

public interface ComputerBuilder {void buildCpu();void buildMemory();void buildStorage();void buildGraphicsCard();void buildPowerSupply();Computer getResult();
}

具体建造者 - 游戏电脑和办公电脑

// 游戏电脑建造者
public class GamingComputerBuilder implements ComputerBuilder {private Computer computer;public GamingComputerBuilder() {this.computer = new Computer();}@Overridepublic void buildCpu() {computer.setCpu("Intel Core i9-13900K");}@Overridepublic void buildMemory() {computer.setMemory("32GB DDR5 RGB");}@Overridepublic void buildStorage() {computer.setStorage("2TB NVMe SSD + 4TB HDD");}@Overridepublic void buildGraphicsCard() {computer.setGraphicsCard("NVIDIA GeForce RTX 4090");}@Overridepublic void buildPowerSupply() {computer.setPowerSupply("1200W 80+ Platinum");}@Overridepublic Computer getResult() {return computer;}
}// 办公电脑建造者
public class OfficeComputerBuilder implements ComputerBuilder {private Computer computer;public OfficeComputerBuilder() {this.computer = new Computer();}@Overridepublic void buildCpu() {computer.setCpu("Intel Core i5-12400");}@Overridepublic void buildMemory() {computer.setMemory("16GB DDR4");}@Overridepublic void buildStorage() {computer.setStorage("512GB NVMe SSD");}@Overridepublic void buildGraphicsCard() {computer.setGraphicsCard("Integrated Intel UHD Graphics");}@Overridepublic void buildPowerSupply() {computer.setPowerSupply("550W 80+ Bronze");}@Overridepublic Computer getResult() {return computer;}
}

工厂方法 - 建造者工厂

public class ComputerBuilderFactory {public enum ComputerType {GAMING, OFFICE}public static ComputerBuilder createBuilder(ComputerType type) {switch (type) {case GAMING:return new GamingComputerBuilder();case OFFICE:return new OfficeComputerBuilder();default:throw new IllegalArgumentException("不支持的电脑类型: " + type);}}
}

指挥者 - ComputerDirector

public class ComputerDirector {public Computer construct(ComputerBuilder builder) {// 统一的构建流程，确保所有电脑都按正确顺序组装builder.buildCpu();builder.buildMemory();builder.buildStorage();builder.buildGraphicsCard();builder.buildPowerSupply();return builder.getResult();}// 可选的快速构建方法public Computer constructGamingComputer() {ComputerBuilder builder = ComputerBuilderFactory.createBuilder(ComputerBuilderFactory.ComputerType.GAMING);return construct(builder);}public Computer constructOfficeComputer() {ComputerBuilder builder = ComputerBuilderFactory.createBuilder(ComputerBuilderFactory.ComputerType.OFFICE);return construct(builder);}
}

客户端使用

public class Client {public static void main(String[] args) {ComputerDirector director = new ComputerDirector();// 方式1：通过工厂方法创建具体建造者，然后指挥者构建System.out.println("=== 方式1：分步构建 ===");ComputerBuilder gamingBuilder = ComputerBuilderFactory.createBuilder(ComputerBuilderFactory.ComputerType.GAMING);Computer gamingComputer = director.construct(gamingBuilder);System.out.println("游戏电脑: " + gamingComputer);// 方式2：直接使用指挥者的快捷方法System.out.println("\n=== 方式2：快捷构建 ===");Computer officeComputer = director.constructOfficeComputer();System.out.println("办公电脑: " + officeComputer);// 方式3：动态根据配置构建System.out.println("\n=== 方式3：动态构建 ===");String userPreference = "performance"; // 可以从配置文件中读取Computer dynamicComputer;if ("performance".equals(userPreference)) {dynamicComputer = director.constructGamingComputer();} else {dynamicComputer = director.constructOfficeComputer();}System.out.println("动态配置电脑: " + dynamicComputer);}
}

✨ 设计模式的优越性体现
🎯 关注点分离与职责清晰

工厂方法专注于创建适当类型的建造者对象

建造者模式专注于分步骤构造复杂产品

指挥者控制构建过程，确保一致性

🔄 极高的灵活性和可扩展性
新增电脑类型时，只需要增加新的具体建造者，无需修改现有代码：

// 新增轻薄本建造者
public class UltrabookComputerBuilder implements ComputerBuilder {// 实现所有构建方法...
}// 在工厂中注册新类型
public static ComputerBuilder createBuilder(ComputerType type) {switch (type) {case GAMING: return new GamingComputerBuilder();case OFFICE: return new OfficeComputerBuilder();case ULTRABOOK: return new UltrabookComputerBuilder(); // 新增default: throw new IllegalArgumentException("不支持的电脑类型: " + type);}
}

🛡️ 构建过程的质量保证
指挥者确保了所有电脑都按照正确的顺序和标准构建：

public Computer construct(ComputerBuilder builder) {// 必须的顺序：先装基础部件，再装扩展部件builder.buildCpu();          // 第一步：安装CPUbuilder.buildMemory();       // 第二步：安装内存builder.buildStorage();      // 第三步：安装存储builder.buildGraphicsCard(); // 第四步：安装显卡builder.buildPowerSupply();  // 第五步：安装电源return builder.getResult();
}