Lombok中的@Builder注解的使用

作用

@Builder注解的作用主要是用来生成对象，并且可以为对象链式赋值。

引入依赖

因为@Builder注解是lombok中的东西，所以第一步我们需要引入lombok的依赖，如下图：

第二步给实体类加上@Builder注解

第二步我们需要给我们的实体类加上一个@Builder注解，如下图：

第三步使用测试使用@Builder注解生成对象

实体类加上@Builder注解之后的编译结果

实体类加上@Builder注解之后，编译之后会多出一个builder()方法，和一个CardBuilder静态内部类，如下图：

代码如下:

public class Card {
    private int id;
    private String name;
    private boolean sex;

    public static Card.CardBuilder builder() {
        return new Card.CardBuilder();
    }

    public Card(int id, String name, boolean sex) {
        this.id = id;
        this.name = name;
        this.sex = sex;
    }

    public Card() {
    }

    public int getId() {
        return this.id;
    }

    public String getName() {
        return this.name;
    }

    public boolean isSex() {
        return this.sex;
    }

    public void setId(int id) {
        this.id = id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setSex(boolean sex) {
        this.sex = sex;
    }

    public boolean equals(Object o) {
        if (o == this) {
            return true;
        } else if (!(o instanceof Card)) {
            return false;
        } else {
            Card other = (Card)o;
            if (!other.canEqual(this)) {
                return false;
            } else if (this.getId() != other.getId()) {
                return false;
            } else {
                Object this$name = this.getName();
                Object other$name = other.getName();
                if (this$name == null) {
                    if (other$name == null) {
                        return this.isSex() == other.isSex();
                    }
                } else if (this$name.equals(other$name)) {
                    return this.isSex() == other.isSex();
                }

                return false;
            }
        }
    }

    protected boolean canEqual(Object other) {
        return other instanceof Card;
    }

    public int hashCode() {
        int PRIME = true;
        int result = 1;
        int result = result * 59 + this.getId();
        Object $name = this.getName();
        result = result * 59 + ($name == null ? 43 : $name.hashCode());
        result = result * 59 + (this.isSex() ? 79 : 97);
        return result;
    }

    public String toString() {
        return "Card(id=" + this.getId() + ", name=" + this.getName() + ", sex=" + this.isSex() + ")";
    }

    public static class CardBuilder {
        private int id;
        private String name;
        private boolean sex;

        CardBuilder() {
        }

        public Card.CardBuilder id(int id) {
            this.id = id;
            return this;
        }

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

        public Card.CardBuilder sex(boolean sex) {
            this.sex = sex;
            return this;
        }

        public Card build() {
            return new Card(this.id, this.name, this.sex);
        }

        public String toString() {
            return "Card.CardBuilder(id=" + this.id + ", name=" + this.name + ", sex=" + this.sex + ")";
        }
    }
}