Java设计模式：建造者模式之经典与流式的三种实现（四）

// 产品类  
public class Product {  
    private String partA;  
    private String partB;  
    private String partC;  
  
    // 构造方法可以是私有的，因为建造者模式可以控制对象的构建过程  
    private Product() {}  
  
    public String getPartA() {  
        return partA;  
    }  
  
    public void setPartA(String partA) {  
        this.partA = partA;  
    }  
  
    // 省略其他getter和setter方法...  
  
    // 静态内部类作为具体建造者  
    public static class Builder {  
        private Product product;  
  
        public Builder() {  
            product = new Product();  
        }  
  
        public Builder setPartA(String partA) {  
            product.partA = partA;  
            return this; // 返回当前Builder实例，以便链式调用  
        }  
  
        public Builder setPartB(String partB) {  
            product.partB = partB;  
            return this;  
        }  
  
        public Builder setPartC(String partC) {  
            product.partC = partC;  
            return this;  
        }  
  
        // 创建并返回产品对象  
        public Product build() {  
            return product;  
        }  
    }  
}  
  
// 客户端代码  
public class Client {  
    public static void main(String[] args) {  
        Product product = new Product.Builder()  
            .setPartA("This is part A")  
            .setPartB("This is part B")  
            .setPartC("This is part C")  
            .build();  
  
        System.out.println(product.getPartA());  
        // 省略访问其他部分...  
    }  
}

// 产品类  
public class Product {  
    private String partA;  
    private String partB;  
    private String partC;  
  
    // 私有构造方法，防止直接实例化  
    private Product() {}  
  
    // 省略getter方法...  
  
    // 静态内部类作为流式建造者  
    public static class Builder {  
        private String partA;  
        private String partB;  
        private String partC;  
  
        public Builder withPartA(String partA) {  
            this.partA = partA;  
            return this;  
        }  
  
        public Builder withPartB(String partB) {  
            this.partB = partB;  
            return this;  
        }  
  
        public Builder withPartC(String partC) {  
            this.partC = partC;  
            return this;  
        }  
  
        // 创建产品对象  
        public Product build() {  
            Product product = new Product();  
            product.partA = this.partA;  
            product.partB = this.partB;  
            product.partC = this.partC;  
            return product;  
        }  
    }  
}  
  
// 客户端代码  
public class Client {  
    public static void main(String[] args) {  
        Product product = new Product.Builder()  
            .withPartA("This is part A")  
            .withPartB("This is part B")  
            .withPartC("This is part C")  
            .build();  
  
        // 省略访问产品属性的代码...  
    }  
}

import lombok.Builder;
import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
@Builder
public class Person {
    private String name;
    private int age;
    private String address;

    // 使用 Lombok @Builder 注解后，无需再手动编写建造者模式的代码
    // Lombok 会在编译时自动生成一个名为 Person.PersonBuilder 的内部类

    // 下面是如何使用生成的建造者类来构建 Person 对象的示例
    public static void main(String[] args) {
        Person person = Person.builder()
                .name("John Doe")
                .age(30)
                .address("123 Main St")
                .build();
        
        System.out.println(person);
    }
}

public class Person {
    private String name;
    private int age;
    private String address;

    private Person(Builder builder) {
        this.name = builder.name;
        this.age = builder.age;
        this.address = builder.address;
    }

    public static class Builder {
        private String name;
        private int age;
        private String address;

        public Builder() {}

        public Builder name(String name) {
            this.name = name;
            return this;
        }

        public Builder age(int age) {
            this.age = age;
            return this;
        }

        public Builder address(String address) {
            this.address = address;
            return this;
        }

        public Person build() {
            return new Person(this);
        }
    }

    // getters, setters, toString, etc.
}