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建造者模式C++

news 2025/8/15 8:54:41

建造者模式（Builder Pattern）是一种创建型设计模式，它将复杂对象的构建过程与表示分离，使得同样的构建过程可以创建不同的表示。这种模式特别适合创建具有多个组成部分、配置复杂的对象。

建造者模式的核心角色

Product（产品）：被构建的复杂对象
Builder（抽象建造者）：定义构建产品各部分的接口
ConcreteBuilder（具体建造者）：实现抽象建造者接口，构建具体产品
Director（指挥者）：控制构建过程，按顺序调用建造者的方法

C++实现示例

以下以"电脑"为例实现建造者模式，电脑由主板、CPU、内存、显卡等部件组成，我们可以通过不同的建造者创建不同配置的电脑。

#include <iostream>
#include <string>
#include <vector>// 产品：电脑
class Computer {
private:std::string motherboard;  // 主板std::string cpu;          // CPUstd::string memory;       // 内存std::string graphicsCard; // 显卡std::string storage;      // 存储设备public:void setMotherboard(const std::string& mb) { motherboard = mb; }void setCPU(const std::string& c) { cpu = c; }void setMemory(const std::string& m) { memory = m; }void setGraphicsCard(const std::string& gc) { graphicsCard = gc; }void setStorage(const std::string& s) { storage = s; }// 显示电脑配置void showConfiguration() const {std::cout << "电脑配置:\n";std::cout << "主板: " << motherboard << "\n";std::cout << "CPU: " << cpu << "\n";std::cout << "内存: " << memory << "\n";std::cout << "显卡: " << graphicsCard << "\n";std::cout << "存储: " << storage << "\n\n";}
};// 抽象建造者
class ComputerBuilder {
public:virtual ~ComputerBuilder() = default;virtual void buildMotherboard() = 0;virtual void buildCPU() = 0;virtual void buildMemory() = 0;virtual void buildGraphicsCard() = 0;virtual void buildStorage() = 0;virtual Computer* getResult() = 0;
};// 具体建造者：游戏电脑建造者
class GamingComputerBuilder : public ComputerBuilder {
private:Computer* computer;public:GamingComputerBuilder() { computer = new Computer(); }~GamingComputerBuilder() { delete computer; }void buildMotherboard() override {computer->setMotherboard("高端游戏主板");}void buildCPU() override {computer->setCPU("高性能多核处理器");}void buildMemory() override {computer->setMemory("32GB 高频内存");}void buildGraphicsCard() override {computer->setGraphicsCard("顶级独立显卡");}void buildStorage() override {computer->setStorage("1TB NVMe SSD");}Computer* getResult() override {return computer;}
};// 具体建造者：办公电脑建造者
class OfficeComputerBuilder : public ComputerBuilder {
private:Computer* computer;public:OfficeComputerBuilder() { computer = new Computer(); }~OfficeComputerBuilder() { delete computer; }void buildMotherboard() override {computer->setMotherboard("普通办公主板");}void buildCPU() override {computer->setCPU("中端处理器");}void buildMemory() override {computer->setMemory("16GB 内存");}void buildGraphicsCard() override {computer->setGraphicsCard("集成显卡");}void buildStorage() override {computer->setStorage("512GB SSD");}Computer* getResult() override {return computer;}
};// 指挥者：指导建造过程
class Director {
public:// 按固定流程构建电脑void construct(ComputerBuilder* builder) {builder->buildMotherboard();builder->buildCPU();builder->buildMemory();builder->buildGraphicsCard();builder->buildStorage();}
};int main() {Director director;// 构建游戏电脑ComputerBuilder* gamingBuilder = new GamingComputerBuilder();director.construct(gamingBuilder);Computer* gamingPC = gamingBuilder->getResult();std::cout << "游戏电脑:\n";gamingPC->showConfiguration();// 构建办公电脑ComputerBuilder* officeBuilder = new OfficeComputerBuilder();director.construct(officeBuilder);Computer* officePC = officeBuilder->getResult();std::cout << "办公电脑:\n";officePC->showConfiguration();// 清理资源delete gamingBuilder;  // 注意：会同时删除内部的Computer对象delete officeBuilder;return 0;
}

代码解析

Computer类：表示被构建的复杂产品，包含多个组件（主板、CPU等）和展示配置的方法。
ComputerBuilder类：抽象建造者，定义了构建电脑各组件的接口方法，以及获取最终产品的方法。
具体建造者：
- GamingComputerBuilder：构建高性能游戏电脑，各组件都选择高端配置
- OfficeComputerBuilder：构建办公电脑，配置满足日常办公需求即可
Director类：指挥者，负责控制构建流程，按固定顺序调用建造者的方法，使构建过程标准化。