[Java知识库]设计模式之建造者模式（Builder模式）

一、UML类图

二、代码示例

• Client:

public class Client {
    public static void main(String[] args) {
        Builder builder = new ConcreteBuilder();
        Director director = new Director(builder);
        director.construct();
        Product product = builder.getProduct();
    }
}

• Builder:

public interface Builder {
    void buildPart1();

    void buildPart2();

    Product getProduct();
}

• ConcreteBuilder:

public class ConcreteBuilder implements Builder{
    private Product product = new Product();

    @Override
    public void buildPart1() {
        product.setPart1("part1");
    }

    @Override
    public void buildPart2() {
        product.setPart2("part2");
    }

    @Override
    public Product getProduct() {
        return product;
    }
}

• Director:

public class Director {
    private Builder builder = null;

    public Director(Builder builder) {
        this.builder = builder;
    }

    public void construct() {
        this.builder.buildPart1();
        this.builder.buildPart2();
    }
}

• Product:

public class Product {
    private String part1;

    private String part2;

    public String getPart1() {
        return part1;
    }

    public void setPart1(String part1) {
        this.part1 = part1;
    }

    public String getPart2() {
        return part2;
    }

    public void setPart2(String part2) {
        this.part2 = part2;
    }
}

三、角色介绍

• Client（客户端）:
  客户端角色，程序的调用者。
• Builder（建造者）:
  负责定义用于生成实例的接口。
• ConcreteBuilder（具体的建造者）:
  负责定义生成实例时实际被调用的方法，并获取最终生成的结果。
• Director（监工）:
  负责使用Builder角色的接口来生成实例。
• Product（产品）:
  所生成的具体实例。