建造者模式（Builder Pattern）：将一个复杂对象的构建与它的表示分离，使得同样的构建过程可以创建不同的表示。建造者模式是一种对象创建型模式。

建造者模式一步一步地创建一个复杂的对象，它允许用户只通过指定复杂对象的类型和内容就可以构建它们，用户不需要知道内部的具体构建细节。

 

// 'Product' 类
public class Product {
    private String partA;
    private String partB;
    private String partC;

    public void setPartA(String partA) {
        this.partA = partA;
    }

    public void setPartB(String partB) {
        this.partB = partB;
    }

    public void setPartC(String partC) {
        this.partC = partC;
    }

    public void showProduct() {
        System.out.println("Part A: " + partA);
        System.out.println("Part B: " + partB);
        System.out.println("Part C: " + partC);
    }
}

// 'Builder' 抽象接口
public interface Builder {
    void buildPartA();
    void buildPartB();
    void buildPartC();

    Product getProduct();
}

// 'ConcreteBuilder1' 类
public class ConcreteBuilder1 implements Builder {
    private Product product = new Product();

    @Override
    public void buildPartA() {
        product.setPartA("This is part A.");
    }

    @Override
    public void buildPartB() {
        product.setPartB("This is part B.");
    }

    @Override
    public void buildPartC() {
        product.setPartC("This is part C.");
    }

    @Override
    public Product getProduct() {
        return product;
    }
}
// 'ConcreteBuilder2' 类
public class ConcreteBuilder2 implements Builder {
    private Product product = new Product();

    @Override
    public void buildPartA() {
        product.setPartA("This is part A.");
    }

    @Override
    public void buildPartB() {
        product.setPartB("This is part B.");
    }

    @Override
    public void buildPartC() {
        product.setPartC("This is part C.");
    }

    @Override
    public Product getProduct() {
        return product;
    }
}
// 'Director' 类
public class Director {
    private Builder builder;

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

    public void constructProduct() {
        builder.buildPartA();
        builder.buildPartB();
        builder.buildPartC();

        Product product = builder.getProduct();
        product.showProduct();
    }
}
// 客户端代码
public class Client {
    public static void main(String[] args) {
        Builder builder1 = new ConcreteBuilder1();
        Director director1 = new Director(builder1);
        director1.constructProduct();

        Builder builder2 = new ConcreteBuilder2();
        Director director2 = new Director(builder2);
        director2.constructProduct();
    }
}