Lombok 类属性

Getter & Setter

public class GetterSetterExample {
  @Getter
  @Setter
  private int age = 10;
  @Setter(AccessLevel.PROTECTED)
  private String name;
  @Override
  public String toString() {
    return String.format("%s (age: %d)", name, age);
  }
}Copy to clipboardErrorCopied

编译之后的代码:

public class GetterSetterExample {
    ...
    public int getAge() {
        return age;
    }
    ...
    public void setAge(int age) {
        this.age = age;
    }
    ...
    protected void setName(String name) {
        this.name = name;
    }
}Copy to clipboardErrorCopied

Accessors

@Accessors(fluent = true)
public class AccessorsExample {
  @Getter
  @Setter
  private int age = 10;
}
class PrefixExample {
  @Accessors(prefix = "f")
  @Getter
  private String fName = "Hello, World!";
}Copy to clipboardErrorCopied

如果设置了 chain 为 true,则仅在 Setter 方法中返回对象,仍然保留标准的 Getter/Setter 风格。

public class AccessorsExample {
  private int age = 10;
  public int age() {
    return this.age;
  }
  public AccessorsExample age(final int age) {
    this.age = age;
    return this;
  }
}
class PrefixExample {
  private String fName = "Hello, World!";
  public String getName() {
    return this.fName;
  }
}Copy to clipboardErrorCopied

Lazy Getter

public class GetterLazyExample {
    @Getter(lazy=true) private final double[] cached = expensive();
    private double[] expensive() {
        ...
    }
}Copy to clipboardErrorCopied

编译之后:

public class GetterLazyExample {
  private final java.util.concurrent.AtomicReference<java.lang.Object> cached = new java.util.concurrent.AtomicReference<java.lang.Object>();
  public double[] getCached() {
    java.lang.Object value = this.cached.get();
    if (value == null) {
      synchronized(this.cached) {
        value = this.cached.get();
        if (value == null) {
          final double[] actualValue = expensive();
          value = actualValue == null ? this.cached : actualValue;
          this.cached.set(value);
        }
      }
    }
    return (double[])(value == this.cached ? null : value);
  }
  private double[] expensive() {
    double[] result = new double[1000000];
    for (int i = 0; i < result.length; i++) {
      result[i] = Math.asin(i);
    }
    return result;
  }
}
}Copy to clipboardErrorCopied

Data

import lombok.AccessLevel;
import lombok.Data;
import lombok.Setter;
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;
  }
}Copy to clipboardErrorCopied

编译后:

import java.util.Arrays;
public class DataExample {
  private final String name;
  private int age;
  private double score;
  private String[] tags;
  public DataExample(String name) {
    this.name = name;
  }
  public String getName() {
    return this.name;
  }
  void setAge(int age) {
    this.age = age;
  }
  public int getAge() {
    return this.age;
  }
  public void setScore(double score) {
    this.score = score;
  }
  public double getScore() {
    return this.score;
  }
  public String[] getTags() {
    return this.tags;
  }
  public void setTags(String[] tags) {
    this.tags = tags;
  }
  @Override
  public String toString() {
    return (
      "DataExample(" +
      this.getName() +
      ", " +
      this.getAge() +
      ", " +
      this.getScore() +
      ", " +
      Arrays.deepToString(this.getTags()) +
      ")"
    );
  }
  protected boolean canEqual(Object other) {
    return other instanceof DataExample;
  }
  @Override
  public boolean equals(Object o) {
    if (o == this) return true;
    if (!(o instanceof DataExample)) return false;
    DataExample other = (DataExample) o;
    if (!other.canEqual((Object) this)) return false;
    if (
      this.getName() == null ? other.getName() != null
        : !this.getName().equals(other.getName())
    ) return false;
    if (this.getAge() != other.getAge()) return false;
    if (Double.compare(this.getScore(), other.getScore()) != 0) return false;
    if (!Arrays.deepEquals(this.getTags(), other.getTags())) return false;
    return true;
  }
  @Override
  public int hashCode() {
    final int PRIME = 59;
    int result = 1;
    final long temp1 = Double.doubleToLongBits(this.getScore());
    result =
      (result * PRIME) +
        (this.getName() == null ? 43 : this.getName().hashCode());
    result = (result * PRIME) + this.getAge();
    result = (result * PRIME) + (int) (temp1 ^ (temp1 >>> 32));
    result = (result * PRIME) + Arrays.deepHashCode(this.getTags());
    return result;
  }
  public static class Exercise<T> {
    private final String name;
    private final T value;
    private Exercise(String name, T value) {
      this.name = name;
      this.value = value;
    }
    public static <T> Exercise<T> of(String name, T value) {
      return new Exercise<T>(name, value);
    }
    public String getName() {
      return this.name;
    }
    public T getValue() {
      return this.value;
    }
    @Override
    public String toString() {
      return (
        "Exercise(name=" + this.getName() + ", value=" + this.getValue() + ")"
      );
    }
    protected boolean canEqual(Object other) {
      return other instanceof Exercise;
    }
    @Override
    public boolean equals(Object o) {
      if (o == this) return true;
      if (!(o instanceof Exercise)) return false;
      Exercise<?> other = (Exercise<?>) o;
      if (!other.canEqual((Object) this)) return false;
      if (
        this.getName() == null ? other.getValue() != null
          : !this.getName().equals(other.getName())
      ) return false;
      if (
        this.getValue() == null ? other.getValue() != null
          : !this.getValue().equals(other.getValue())
      ) return false;
      return true;
    }
    @Override
    public int hashCode() {
      final int PRIME = 59;
      int result = 1;
      result =
        (result * PRIME) +
          (this.getName() == null ? 43 : this.getName().hashCode());
      result =
        (result * PRIME) +
          (this.getValue() == null ? 43 : this.getValue().hashCode());
      return result;
    }
  }
}Copy to clipboardErrorCopied
下一节:ModelMapper 是一个从对象到对象(object-to-object)的框架,能将 Java Bean(Pojo)对象从一种表现形式转化为另一种表现形式。它采用“通过约定来配置”的方式,自动匹配不同的对象映射,同时具备满足某些特殊需求的高级功能。这与.NET 的 AutoMapper 库很类似(但不是直接移植)。