spingboot的lombok的使用

ゝ一纸荒年。 2022-05-12 14:04 124阅读 0赞

lombok 是采用注解用于自动为 POJO 生成 getter()、setter()、hashCode()、toString() 等方法的第三方类库。其常用注解介绍如下：  
1) @Getter / @Setter：可以作用在类上和属性上，放在类上，会对所有的非静态(non-static)属性生成Getter/Setter方法，放在属性上，会对该属性生成Getter/Setter方法。并可以指定Getter/Setter方法的访问级别。  
2) @EqualsAndHashCode ：默认情况下，会使用所有非瞬态(non-transient)和非静态(non-static)字段来生成equals和hascode方法，也可以指定具体使用哪些属性。 @ToString 生成toString方法，默认情况下，会输出类名、所有属性，属性会按照顺序输出，以逗号分割。  
3) @NoArgsConstructor, @RequiredArgsConstructor and @AllArgsConstructor：无参构造器、部分参数构造器、全参构造器

4) @Data：包含@ToString, @EqualsAndHashCode, 所有属性的@Getter, 所有non-final属性的@Setter和     @RequiredArgsConstructor的组合，通常情况下，基本上使用这个注解就足够了。

5) @Budilder：可以进行Builder方式初始化。

6) @Slf4j：等同于：private final Logger logger = LoggerFactory.getLogger(XXX.class);简直不能更爽了！一般上用在其他java类上

1、在pom.xml文件引入lombok的依赖

<dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.16.22</version>
                <scope>provided</scope>
           </dependency>
           
            <dependency>
                     <groupId>org.springframework.boot</groupId>
                     <artifactId>spring-boot-configuration-processor</artifactId>
                     <optional>true</optional>
            </dependency>

2、在实体bean的类名上加上@Data

package com.example.demo.entity;
    
    import lombok.Data;
    import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.context.annotation.PropertySource;
    import org.springframework.stereotype.Component;
    
    import java.util.List;
    
    @Data
    @Component
    @ConfigurationProperties(prefix="config")
    public class MyConfig {
    
        private String name;
        private Byte age;
        private List<String> hobby;
    
    }

编译后会自动生成所有属性，如下：

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by Fernflower decompiler)
    //
    
    package com.example.demo.entity;
    
    import java.util.List;
    import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.stereotype.Component;
    
    @Component
    @ConfigurationProperties(
        prefix = "config"
    )
    public class MyConfig {
        private String name;
        private Byte age;
        private List<String> hobby;
    
        public MyConfig() {
        }
    
        public String getName() {
            return this.name;
        }
    
        public Byte getAge() {
            return this.age;
        }
    
        public List<String> getHobby() {
            return this.hobby;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public void setAge(Byte age) {
            this.age = age;
        }
    
        public void setHobby(List<String> hobby) {
            this.hobby = hobby;
        }
    
        public boolean equals(Object o) {
            if (o == this) {
                return true;
            } else if (!(o instanceof MyConfig)) {
                return false;
            } else {
                MyConfig other = (MyConfig)o;
                if (!other.canEqual(this)) {
                    return false;
                } else {
                    label47: {
                        Object this$name = this.getName();
                        Object other$name = other.getName();
                        if (this$name == null) {
                            if (other$name == null) {
                                break label47;
                            }
                        } else if (this$name.equals(other$name)) {
                            break label47;
                        }
    
                        return false;
                    }
    
                    Object this$age = this.getAge();
                    Object other$age = other.getAge();
                    if (this$age == null) {
                        if (other$age != null) {
                            return false;
                        }
                    } else if (!this$age.equals(other$age)) {
                        return false;
                    }
    
                    Object this$hobby = this.getHobby();
                    Object other$hobby = other.getHobby();
                    if (this$hobby == null) {
                        if (other$hobby != null) {
                            return false;
                        }
                    } else if (!this$hobby.equals(other$hobby)) {
                        return false;
                    }
    
                    return true;
                }
            }
        }
    
        protected boolean canEqual(Object other) {
            return other instanceof MyConfig;
        }
    
        public int hashCode() {
            int PRIME = true;
            int result = 1;
            Object $name = this.getName();
            int result = result * 59 + ($name == null ? 43 : $name.hashCode());
            Object $age = this.getAge();
            result = result * 59 + ($age == null ? 43 : $age.hashCode());
            Object $hobby = this.getHobby();
            result = result * 59 + ($hobby == null ? 43 : $hobby.hashCode());
            return result;
        }
    
        public String toString() {
            return "MyConfig(name=" + this.getName() + ", age=" + this.getAge() + ", hobby=" + this.getHobby() + ")";
        }
    }