Lombok的使用

IDEA安装插件：

添加Lombok IntelliJ插件以添加对IntelliJ的lombok支持：

• 去 File > Settings > Plugins
• 点击 Browse repositories...
• 搜索 Lombok Plugin
• 点击 Install plugin
• 重启IntelliJ IDEA

pom依赖：

        <!--@Data注解-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.10</version>
        </dependency>

@NonNull：

null检查看起来像if (param == null) throw new NullPointerException("param is marked @NonNull but is null");将被插入到方法的最顶层

 import lombok.NonNull;

public class NonNullExample extends Something {
  private String name;
  
  public NonNullExample(@NonNull Person person) {
    super("Hello");
    this.name = person.getName();
  }
}

　　

@Getter和@Setter

让lombok自动生成默认的getter / setter。

 import lombok.AccessLevel;
import lombok.Getter;
import lombok.Setter;

public class GetterSetterExample {
  /**
   * Age of the person. Water is wet.
   * 
   * @param age New value for this person's age. Sky is blue.
   * @return The current value of this person's age. Circles are round.
   */
  @Getter @Setter private int age = 10;
  
  /**
   * Name of the person.
   * -- SETTER --
   * Changes the name of this person.
   * 
   * @param name The new value.
   */
  @Setter(AccessLevel.PROTECTED) private String name;
  
  @Override public String toString() {
    return String.format("%s (age: %d)", name, age);
  }
}

@EqualsAndHashCode ：

默认情况下生成非静态非final字段的equals和hashcode，可以使用@EqualsAndHashCode.Include 来标记使用哪些字段@EqualsAndHashCode(onlyExplicitlyIncluded = true)，或者@EqualsAndHashCode.Exclude 来排除哪些字段，设置(callSuper=true)来确定是否使用超类字段。

 import lombok.EqualsAndHashCode;

@EqualsAndHashCode
public class EqualsAndHashCodeExample {
  private transient int transientVar = 10;
  private String name;
  private double score;
  @EqualsAndHashCode.Exclude private Shape shape = new Square(5, 10);
  private String[] tags;
  @EqualsAndHashCode.Exclude private int id;
  
  public String getName() {
    return this.name;
  }
  
  @EqualsAndHashCode(callSuper=true)
  public static class Square extends Shape {
    private final int width, height;
    
    public Square(int width, int height) {
      this.width = width;
      this.height = height;
    }
  }
}

@NoArgsConstructor，@ RequiredArgsConstructor，@ AllArgsConstructor

生成构造器

 import lombok.AccessLevel;
import lombok.RequiredArgsConstructor;
import lombok.AllArgsConstructor;
import lombok.NonNull;

@RequiredArgsConstructor(staticName = "of")
@AllArgsConstructor(access = AccessLevel.PROTECTED)
public class ConstructorExample<T> {
  private int x, y;
  @NonNull private T description;
  
  @NoArgsConstructor
  public static class NoArgsExample {
    @NonNull private String field;
  }
}

@data

@Data具有隐式@Getter，@Setter，@ToString，@EqualsAndHashCode和@RequiredArgsConstructor

 import lombok.AccessLevel;
import lombok.Setter;
import lombok.Data;
import lombok.ToString;

@Data public class DataExample {
  private final String name;
  @Setter(AccessLevel.PACKAGE) private int age;
  private double score;
  private String[] tags;
  
  @ToString(includeFieldNames=true)
  @Data(staticConstructor="of")
  public static class Exercise<T> {
    private final String name;
    private final T value;
  }
}

@Slf4j和@Log

等同于：private static final java.util.logging.Logger log = java.util.logging.Logger.getLogger(LogExample.class.getName());

private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(LogExampleOther.class);

 import lombok.extern.java.Log;
import lombok.extern.slf4j.Slf4j;

@Log
public class LogExample {
  
  public static void main(String... args) {
    log.severe("Something's wrong here");
  }
}

@Slf4j
public class LogExampleOther {
  
  public static void main(String... args) {
    log.error("Something else is wrong here");
  }
}

@CommonsLog(topic="CounterLog")
public class LogExampleCategory {

  public static void main(String... args) {
    log.error("Calling the 'CounterLog' with a message");
  }
}