建造者模式

public abstract class Builder {
    public abstract void buildPartA();
    public abstract void buildPartB();
    public abstract Product getResult();
}

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

    @Override
    public void buildPartA() {
        product.add("部件A");
        
    }

    @Override
    public void buildPartB() {
        product.add("部件B");
        
    }

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

import java.util.ArrayList;
import java.util.List;

public class Product {
    List<String> parts = new ArrayList<String>();
    
    public void add(String part){
        parts.add(part);
    }
    
    public void show(){
        System.out.println("组成部件：\t");
        for (String str : parts) {
            System.out.print(str+"\t");
        }
    }
}

public class Director {
    public void construct(Builder builder){
        builder.buildPartA();
        builder.buildPartB();
    }
}

public class TestBuilder {
    public static void main(String[] args) {
        Director di = new Director();
        Builder builder = new ConcreteBuilder();
        di.construct(builder);
        Product pr = builder.getResult();
        pr.show();
    }
}

结果：
组成部件：    
部件A    部件B