你还在new对象吗？Java8通用Builder了解一下？

 1public class GirlFriend {
 2
 3    private String name;
 4    private int age;
 5
 6    // 省略 getter & setter ...
 7
 8    public static void main(String[] args) {
 9        GirlFriend myGirlFriend = new GirlFriend();
10        myGirlFriend.setName("小美");
11        myGirlFriend.setAge(18);
12    }
13}

 1public class GirlFriend {
 2
 3    private String name;
 4    private int age;
 5    private int bust;
 6    private int waist;
 7    private int hips;
 8    private List<String> hobby;
 9    private String birthday;
10    private String address;
11    private String mobile;
12    private String email;
13    private String hairColor;
14    private Map<String, String> gift;
15    // 等等等等 ...
16
17    // 省略 getter & setter ...
18
19    public static void main(String[] args) {
20        GirlFriend myGirlFriend = new GirlFriend();
21        myGirlFriend.setName("小美");
22        myGirlFriend.setAge(18);
23        myGirlFriend.setBust(33);
24        myGirlFriend.setWaist(23);
25        myGirlFriend.setHips(33);
26        myGirlFriend.setBirthday("2001-10-26");
27        myGirlFriend.setAddress("上海浦东");
28        myGirlFriend.setMobile("18688888888");
29        myGirlFriend.setEmail("pretty-xiaomei@qq.com");
30        myGirlFriend.setHairColor("浅棕色带点微卷");
31        List<String> hobby = new ArrayList<>();
32        hobby.add("逛街");
33        hobby.add("购物");
34        hobby.add("买东西");
35        myGirlFriend.setHobby(hobby);
36        Map<String, String> gift = new HashMap<>();
37        gift.put("情人节礼物", "LBR 1912女王时代");
38        gift.put("生日礼物", "迪奥烈焰蓝金");
39        gift.put("纪念日礼物", "阿玛尼红管唇釉");
40        myGirlFriend.setGift(gift);
41        // 等等等等 ...
42    }
43}

 1GirlFriend{name='小美'
 2, age=18
 3, bust=33
 4, waist=23
 5, hips=33
 6, hobby=[逛街, 购物, 买东西]
 7, birthday='2001-10-26'
 8, address='上海浦东'
 9, mobile='18688888888'
10, email='pretty-xiaomei@qq.com'
11, hairColor='浅棕色带点微卷'
12, gift={情人节礼物=LBR 1912女王时代, 生日礼物=迪奥烈焰蓝金, 纪念日礼物=阿玛尼红管唇釉}
13}

 1public class GirlFriend {
 2
 3    // 省略属性 ...
 4
 5    // 省略 getter & setter ...
 6
 7    // 为了演示方便，加几个聚合方法
 8    public void addHobby(String hobby) {
 9        this.hobby = Optional.ofNullable(this.hobby).orElse(new ArrayList<>());
10        this.hobby.add(hobby);
11    }
12
13    public void addGift(String day, String gift) {
14        this.gift = Optional.ofNullable(this.gift).orElse(new HashMap<>());
15        this.gift.put(day, gift);
16    }
17
18    public void setVitalStatistics(int bust, int waist, int hips) {
19        this.bust = bust;
20        this.waist = waist;
21        this.hips = hips;
22    }
23
24    public static void main(String[] args) {
25        GirlFriend myGirlFriend = Builder.of(GirlFriend::new)
26                .with(GirlFriend::setName, "小美")
27                .with(GirlFriend::setAge, 18)
28                .with(GirlFriend::setVitalStatistics, 33, 23, 33)
29                .with(GirlFriend::setBirthday, "2001-10-26")
30                .with(GirlFriend::setAddress, "上海浦东")
31                .with(GirlFriend::setMobile, "18688888888")
32                .with(GirlFriend::setEmail, "pretty-xiaomei@qq.com")
33                .with(GirlFriend::setHairColor, "浅棕色带点微卷")
34                .with(GirlFriend::addHobby, "逛街")
35                .with(GirlFriend::addHobby, "购物")
36                .with(GirlFriend::addHobby, "买东西")
37                .with(GirlFriend::addGift, "情人节礼物", "LBR 1912女王时代")
38                .with(GirlFriend::addGift, "生日礼物", "迪奥烈焰蓝金")
39                .with(GirlFriend::addGift, "纪念日礼物", "阿玛尼红管唇釉")
40                // 等等等等 ...
41                .build();
42    }
43}

 1/**
 2 * 通用的 Builder 模式构建器
 3 *
 4 * @author: CipherCui
 5 * @since 2019/8/29
 6 */
 7public class Builder<T> {
 8
 9    private final Supplier<T> instantiator;
10    private List<Consumer<T>> modifiers = new ArrayList<>();
11
12    public Builder(Supplier<T> instantiator) {
13        this.instantiator = instantiator;
14    }
15
16    public static <T> Builder<T> of(Supplier<T> instantiator) {
17        return new Builder<>(instantiator);
18    }
19
20    public <P1> Builder<T> with(Consumer1<T, P1> consumer, P1 p1) {
21        Consumer<T> c = instance -> consumer.accept(instance, p1);
22        modifiers.add(c);
23        return this;
24    }
25
26    public <P1, P2> Builder<T> with(Consumer2<T, P1, P2> consumer, P1 p1, P2 p2) {
27        Consumer<T> c = instance -> consumer.accept(instance, p1, p2);
28        modifiers.add(c);
29        return this;
30    }
31
32    public <P1, P2, P3> Builder<T> with(Consumer3<T, P1, P2, P3> consumer, P1 p1, P2 p2, P3 p3) {
33        Consumer<T> c = instance -> consumer.accept(instance, p1, p2, p3);
34        modifiers.add(c);
35        return this;
36    }
37
38    public T build() {
39        T value = instantiator.get();
40        modifiers.forEach(modifier -> modifier.accept(value));
41        modifiers.clear();
42        return value;
43    }
44
45    /**
46     * 1 参数 Consumer
47     */
48    @FunctionalInterface
49    public interface Consumer1<T, P1> {
50        void accept(T t, P1 p1);
51    }
52
53    /**
54     * 2 参数 Consumer
55     */
56    @FunctionalInterface
57    public interface Consumer2<T, P1, P2> {
58        void accept(T t, P1 p1, P2 p2);
59    }
60
61    /**
62     * 3 参数 Consumer
63     */
64    @FunctionalInterface
65    public interface Consumer3<T, P1, P2, P3> {
66        void accept(T t, P1 p1, P2 p2, P3 p3);
67    }
68}