Lombok中的@Builder注解的使用

川长思鸟来 2024-03-03 00:48 76阅读 0赞

## 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：
 *  ![在这里插入图片描述][0ffdbb4f7d76486887db63ca4788eb5d.png]

### 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：
 *  ![在这里插入图片描述][27af5e43f2ee4f0e82b3c624d36962af.png]

### 第三步使用测试使用@Builder注解生成对象 ###

*  ![在这里插入图片描述][1a9cbf9f1a7243ddb3b0b06c061b8caa.png]

### 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：
 *  ![在这里插入图片描述][98f1030957064f5994c0bfc00553d988.png]
 *  ![在这里插入图片描述][e05bd73dc96b4d509da7fbc44346ccc5.png]
 *  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 + ")";
                }
            }
        }

[0ffdbb4f7d76486887db63ca4788eb5d.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/03/87eb2f1dde91482ba16cd12059044944.png
[27af5e43f2ee4f0e82b3c624d36962af.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/03/014d8aa7bbb7492e9e5503f371e7df78.png
[1a9cbf9f1a7243ddb3b0b06c061b8caa.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/03/e5bd048655db46b0955d843064966288.png
[98f1030957064f5994c0bfc00553d988.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/03/2759f69b79914438a19b9a1e9a1a400d.png
[e05bd73dc96b4d509da7fbc44346ccc5.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/03/d5b2809e12954059b2f5dd0371112d0e.png