你还在new对象吗？Java8通用Builder了解一下？

程序员经常会遇到灵魂拷问：你有对象吗？没有，但我可以 new 一个！

public class GirlFriend {
  private String name ;
  private int age ;
  // 省略 getter & setter ...
  public static void main ( String [] args ) {
    GirlFriend myGirlFriend  = new GirlFriend();
    myGirlFriend.setName("小美");
    myGirlFriend.setAge(18);
  }
}

没问题，老铁！但如果对象的属性太多，咋办？
莫慌，看法宝~
这里不再介绍其他 Builder 实现方式，直接祭出最实用的通用Builder：
适用于所有类，不需要改造原来类，不需要 lombok 插件支持。
先看看使用姿势：

public class GirlFriend {
  // 省略属性 ...
  // 省略 getter & setter ...
  public static void main ( String[] args ) {
  GirlFriend myGirlFriend = BuilderUtil.of(GirlFriend::new)
    .with(GirlFriend::setName, "小美")
    .with(GirlFriend::setAge, 18)
    .with(GirlFriend::setVitalStatistics, 33, 23, 33)
    .with(GirlFriend::setBirthday, "2001-10-26")
    .with(GirlFriend::setAddress, "上海浦东")
    .with(GirlFriend::setMobile, "18688888888")
    .with(GirlFriend::setEmail, "pretty-xiaomei@qq.com")
    .with(GirlFriend::setHairColor, "浅棕色带点微卷")
    .with(GirlFriend::addHobby, "逛街")
    .with(GirlFriend::addHobby, "购物")
    .with(GirlFriend::addHobby, "买东西")
    .with(GirlFriend::addGift, "情人节礼物", "LBR 1912女王时代")
    .with(GirlFriend::addGift, "生日礼物", "迪奥烈焰蓝金")
    // 等等等等 ..
    .build();
  }
}

看到了吗！实例化和属性设置在同一条语句执行，链式操作，一路点点点，清爽！
Talk is cheap, show me the code：

/**
 * @author wang.n
 * @date 2021/2/9 8:42
 * @e-mail wang.n_988@foxmail.com
 */
public class BuilderUtil<T> {
    private final Supplier<T> instantiator;

    private List<Consumer<T>> modifiers = new ArrayList<>();

    public BuilderUtil(Supplier<T> instantiator ) {
        this.instantiator = instantiator ;
    }

    public static <T> BuilderUtil<T> of(Supplier<T> instantiator ) {
        return new BuilderUtil<>(instantiator);
    }

    public <P1> BuilderUtil<T> with(Consumer1<T, P1> consumer, P1 p1) {
        Consumer<T> c = instance -> consumer.accept(instance, p1);
        modifiers.add(c);
        return this;
    }

    public<P1, P2> BuilderUtil<T> with(Consumer2<T, P1, P2> consumer, P1 p1, P2 p2) {
        Consumer<T> c = instance -> consumer.accept( instance, p1, p2);
        modifiers.add(c);
        return this;
    }

    public<P1, P2, P3> BuilderUtil<T> with(Consumer3<T, P1, P2, P3> consumer, P1 p1, P2 p2, P3 p3){
        Consumer<T> c = instance -> consumer.accept(instance,p1,p2, p3);
        modifiers.add(c);
        return this;
    }

    public T build() {
        T value = instantiator.get();
        modifiers.forEach( modifier -> modifier.accept(value));
        modifiers.clear();
        return value;
    }

    /**
     * 1 参数 Consumer
     */
    @FunctionalInterface
    public interface Consumer1<T, P1>{
        void accept ( T t, P1 p1);
    }

    /**
     * 2 参数 Consumer
     */
    @FunctionalInterface
    public interface Consumer2< T, P1, P2> {
        void accept( T t, P1 p1, P2 p2);
    }

    /**
     * 3 参数 Consumer
     */
    @FunctionalInterface
    public interface Consumer3< T, P1, P2, P3> {
        void accept( T t, P1 p1, P2 p2, P3 p3);
    }
}

这个示例最多支持三个参数的设置属性方法，也完全够用了。如果要扩展也很容易，依葫芦画瓢，添加多个参数的Consumer。

快用你的 Builder 建个对象吧~