程序員經(jīng)常會(huì)遇到靈魂拷問：你有對(duì)象嗎？

沒有，但我可以 new 一個(gè)！

public class GirlFriend {

private String name;

private int age;

// 省略 getter & setter ...

public satic void main(String[] args) {

GirlFriend myGirlFriend = new GirlFriend();

myGirlFriend.setName("小美");

myGirlFriend.setAge(18);

}

}

但如果對(duì)象的屬性太多，咋辦？

public class GirlFriend {

private String name;

private int age;

private int bust;

private int waist;

private int hips;

private List hobby;

private String birthday;

private String address;

private String mobile;

private String email;

private String hairColor;

private Map gift;

// 等等等等 ...

// 省略 getter & setter ...

public static void main(String[] args) {

GirlFriend myGirlFriend = new GirlFriend();

myGirlFriend.setName("小美");

myGrlFriend.setAge(18);

myGirlFriend.setBust(33);

myGirlFriend.setWaist(23);

myGirlFriend.setHips(33);

myGirlFriend.setBirthday("2001-10-26");

myGirlFriend.setAddress("上海浦東");

myGirlFriend.setMobile("18688888888");

myGirlFriend.setEmail("pretty-xiaomei@qq.com");

myGirlFriend.setHairColor("淺棕色帶點(diǎn)微卷");

List hobby = new ArrayList<>();

hobby.add("逛街");

hobby.add("購物");

hobby.add("買東西");

myGirlFriend.setHobby(hobby);

Map gift = new HashMap<>();

gift.put("情人節(jié)禮物", "LBR 1912女王時(shí)代");

gift.put("生日禮物", "迪奧烈焰藍(lán)金");

gift.put("紀(jì)念日禮物", "阿瑪尼紅管唇釉");

myGirlFriend.setGift(gift);

// 等等等等 ...

}

}

GirlFriend

GirlFriend{name='小美'

, age=18

, bust=33

, waist=23

, hips=33

, hobby=[逛街, 購物, 買東西]

, birthday='2001-10-26'

, address='上海浦東'

, mobile='18688888888'

, email='pretty-xiaomei@qq.com'

, hairColor='淺棕色帶點(diǎn)微卷'

, gift={情人節(jié)禮物=LBR 1912女王時(shí)代, 生日禮物=迪奧烈焰藍(lán)金, 紀(jì)念日禮物=阿瑪尼紅管唇釉}

}

GirlFriend 是很美，但寫起來也太麻煩了吧。

說說缺點(diǎn)：實(shí)例化和設(shè)置屬性分開，不好維護(hù)；變量名重復(fù)寫。

莫慌，看法寶~

這里不再介紹其他 Builder 實(shí)現(xiàn)方式，直接祭出最實(shí)用的通用Builder：

適用于所有類，不需要改造原來類，不需要 lombok 插件支持。

先看看使用姿勢(shì)：

public class GirlFriend {

// 省略屬性 ...

// 省略 getter & setter ...

// 為了演示方便，加幾個(gè)聚合方法

public void addHobby(String hobby) {

this.hobby = Optional.ofNullable(this.hobby).orElse(new ArrayList<>());

this.hobby.add(hobby);

}

public void addGift(String day, String gift) {

this.gift = Optional.ofNullable(this.gift).orElse(new HashMap<>());

this.gift.put(day, gift);

}

public void setVitalStatistics(int bust, int waist, int hips) {

this.bust = bust;

this.waist = waist;

this.hips = hips;

}

public static void main(String[] args) {

GirlFriend myGirlFriend = Builder.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, "上海浦東")

.with(GirlFriend::setMobile, "18688888888")

.with(GirlFriend::setEmail, "pretty-xiaomei@qq.com")

.with(GirlFriend::setHairColor, "淺棕色帶點(diǎn)微卷")

.with(GirlFriend::addHobby, "逛街")

.with(GirlFriend::addHobby, "購物")

.with(GirlFriend::addHobby, "買東西")

.with(GirlFriend::addGift, "情人節(jié)禮物", "LBR 1912女王時(shí)代")

.with(GirlFriend::addGift, "生日禮物", "迪奧烈焰藍(lán)金")

.with(GirlFriend::addGift, "紀(jì)念日禮物", "阿瑪尼紅管唇釉")

// 等等等等 ...

.build();

}

}

看到了嗎！實(shí)例化和屬性設(shè)置在同一條語句執(zhí)行，鏈?zhǔn)讲僮?#xff0c;一路點(diǎn)點(diǎn)點(diǎn)，清爽！

Talk is cheap, show me the code：

/**

* 通用的 Builder 模式構(gòu)建器

*

* @author: CipherCui

* @since 2019/8/29

*/

public class Builder {

private final Supplier instantiator;

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

public Builder(Supplier instantiator) {

this.instantiator = instantiator;

}

public static Builder of(Supplier instantiator) {

return new Builder<>(instantiator);

}

public Builder with(Consumer1 consumer, P1 p1) {

Consumer c = instance -> consumer.accept(instance, p1);

modifiers.add(c);

return this;

}

public Builder with(Consumer2 consumer, P1 p1, P2 p2) {

Consumer c = instance -> consumer.accept(instance, p1, p2);

modifiers.add(c);

return this;

}

public Builder with(Consumer3 consumer, P1 p1, P2 p2, P3 p3) {

Consumer 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 參數(shù) Consumer

*/

@FunctionalInterface

public interface Consumer1 {

void accept(T t, P1 p1);

}

/**

* 2 參數(shù) Consumer

*/

@FunctionalInterface

public interface Consumer2 {

void accept(T t, P1 p1, P2 p2);

}

/**

* 3 參數(shù) Consumer

*/

@FunctionalInterface

public interface Consumer3 {

void accept(T t, P1 p1, P2 p2, P3 p3);

}

}

這個(gè)示例最多支持三個(gè)參數(shù)的設(shè)置屬性方法，也完全夠用了。如果要擴(kuò)展也很容易，依葫蘆畫瓢，添加多個(gè)參數(shù)的Consumer。

快用你的 Builder 建個(gè)對(duì)象吧~

本內(nèi)容屬于網(wǎng)絡(luò)轉(zhuǎn)載，文中涉及圖片等內(nèi)容如有侵權(quán)，請(qǐng)聯(lián)系編輯刪除

總結(jié)

以上是生活随笔為你收集整理的java emailbuilder 样式_Java8通用Builder了解一下的全部內(nèi)容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網(wǎng)站內(nèi)容還不錯(cuò)，歡迎將生活随笔推薦給好友。