1.安装插件
1.找到lombok-1.18.12.jar
java -jar ./lombok-1.18.12.jar
2.选择Eclipse对应的安装位置之后安装
3.安装成功在eclipse目录会生成lombok.jar
同时eclipse.ini也会增加一行：
-javaagent:E:Eclipseeclipse-jee-mars-1-win32-x86_64eclipse-jee-mars-1-win32-x86_64eclipselombok.jar
4.重启eclipse即可
二、lombok简单使用
pom文件引入依赖：
<dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency>
1.测试常用注解@Getter、@Setter、@EqualsAndHashCode、@ToString
package cn.qlq.lombok; import lombok.EqualsAndHashCode; import lombok.Getter; import lombok.Setter; import lombok.ToString; @Getter @Setter @EqualsAndHashCode @ToString public class User { private long id; private String username; }
jd反编译后查看代码：
package cn.qlq.lombok; public class User { private long id; private String username; public String getUsername() { return this.username; } public long getId() { return this.id; } public void setUsername(String username) { this.username = username; } public void setId(long id) { this.id = id; } protected boolean canEqual(Object other) { return other instanceof User; } public int hashCode() { int PRIME = 59;int result = 1;long $id = getId();result = result * 59 + (int)($id ^ $id >>> 32);Object $username = getUsername();result = result * 59 + ($username == null ? 43 : $username.hashCode());return result; } public boolean equals(Object o) { if (o == this) { return true; } if (!(o instanceof User)) { return false; } User other = (User)o; if (!other.canEqual(this)) { return false; } if (getId() != other.getId()) { return false; } Object this$username = getUsername();Object other$username = other.getUsername();return this$username == null ? other$username == null : this$username.equals(other$username); } public String toString() { return "User(id=" + getId() + ", username=" + getUsername() + ")"; } }
2.@NoArgsConstructor 、@AllArgsConstructor分别用于无参构造和有参构造
package cn.qlq.lombok; import lombok.AllArgsConstructor; import lombok.NoArgsConstructor; @NoArgsConstructor // 无参构造 @AllArgsConstructor // 有参构造 public class User { private long id; private String username; }
反编译查看代码：
package cn.qlq.lombok; public class User { private long id; private String username; public User() {} public User(long id, String username) { this.id = id;this.username = username; } }
3.@Data 相当于@Getter、@Setter、@EqualsAndHashCode、@ToString
package cn.qlq.lombok; import lombok.Data; @Data public class User { private long id; private String username; }
反编译查看：
package cn.qlq.lombok; public class User { private long id; private String username; public String toString() { return "User(id=" + getId() + ", username=" + getUsername() + ")"; } public int hashCode() { int PRIME = 59;int result = 1;long $id = getId();result = result * 59 + (int)($id ^ $id >>> 32);Object $username = getUsername();result = result * 59 + ($username == null ? 43 : $username.hashCode());return result; } protected boolean canEqual(Object other) { return other instanceof User; } public boolean equals(Object o) { if (o == this) { return true; } if (!(o instanceof User)) { return false; } User other = (User)o; if (!other.canEqual(this)) { return false; } if (getId() != other.getId()) { return false; } Object this$username = getUsername();Object other$username = other.getUsername();return this$username == null ? other$username == null : this$username.equals(other$username); } public void setUsername(String username) { this.username = username; } public void setId(long id) { this.id = id; } public String getUsername() { return this.username; } public long getId() { return this.id; } }
查看@Data源码如下：其实还有@RequiredArgsConstructor ，只是这个注解一般不用。
/** <a href="http://www.cpupk.com/decompiler">Eclipse Class Decompiler</a> plugin, Copyright (c) 2017 Chen Chao. */ package lombok; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; /** * Generates getters for all fields, a useful toString method, and hashCode and equals implementations that check * all non-transient fields. Will also generate setters for all non-final fields, as well as a constructor. * <p> * Equivalent to {@code @Getter @Setter @RequiredArgsConstructor @ToString @EqualsAndHashCode}. * <p> * Complete documentation is found at <a href="https://projectlombok.org/features/Data">the project lombok features page for @Data</a>. * * @see Getter * @see Setter * @see RequiredArgsConstructor * @see ToString * @see EqualsAndHashCode * @see lombok.Value */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.SOURCE) public @interface Data { /** * If you specify a static constructor name, then the generated constructor will be private, and * instead a static factory method is created that other classes can use to create instances. * We suggest the name: "of", like so: * * <pre> * public @Data(staticConstructor = "of") class Point { final int x, y; } * </pre> * * Default: No static constructor, instead the normal constructor is public. * * @return Name of static 'constructor' method to generate (blank = generate a normal constructor). */ String staticConstructor() default ""; }
需要注意：@Data生成toString和equals、hashCode时不会选择父类的字段，如下：
父类：
package cn.qlq.lombok; import java.io.Serializable; import lombok.Data; @Data public abstract class AbstractSequenceEntity implements Serializable { private static final long serialVersionUID = 7304379208787774552L; protected Long id; }
反编译查看：
package cn.qlq.lombok; import java.io.Serializable; public abstract class AbstractSequenceEntity implements Serializable { private static final long serialVersionUID = 7304379208787774552L; protected Long id; public String toString() { return "AbstractSequenceEntity(id=" + getId() + ")"; } public int hashCode() { int PRIME = 59;int result = 1;Object $id = getId();result = result * 59 + ($id == null ? 43 : $id.hashCode());return result; } protected boolean canEqual(Object other) { return other instanceof AbstractSequenceEntity; } public boolean equals(Object o) { if (o == this) { return true; } if (!(o instanceof AbstractSequenceEntity)) { return false; } AbstractSequenceEntity other = (AbstractSequenceEntity)o; if (!other.canEqual(this)) { return false; } Object this$id = getId();Object other$id = other.getId();return this$id == null ? other$id == null : this$id.equals(other$id); } public void setId(Long id) { this.id = id; } public Long getId() { return this.id; } }
子类如下：
package cn.qlq.lombok; import lombok.Data; @Data public class User extends AbstractSequenceEntity { private static final long serialVersionUID = 1487903039867324395L; private String username; }
反编译查看：没有从父类继承的属性
package cn.qlq.lombok; public class User extends AbstractSequenceEntity { private static final long serialVersionUID = 1487903039867324395L; private String username; public String toString() { return "User(username=" + getUsername() + ")"; } public int hashCode() { int PRIME = 59;int result = 1;Object $username = getUsername();result = result * 59 + ($username == null ? 43 : $username.hashCode());return result; } protected boolean canEqual(Object other) { return other instanceof User; } public boolean equals(Object o) { if (o == this) { return true; } if (!(o instanceof User)) { return false; } User other = (User)o; if (!other.canEqual(this)) { return false; } Object this$username = getUsername();Object other$username = other.getUsername();return this$username == null ? other$username == null : this$username.equals(other$username); } public void setUsername(String username) { this.username = username; } public String getUsername() { return this.username; } }
解决办法：
package cn.qlq.lombok; import lombok.EqualsAndHashCode; import lombok.Getter; import lombok.Setter; import lombok.ToString; @Getter @Setter // callSuper： 是否包含父类的属性 @ToString(callSuper = true) @EqualsAndHashCode(callSuper = true) public class User extends AbstractSequenceEntity { private static final long serialVersionUID = 1487903039867324395L; private String username; }
反编译查看：
package cn.qlq.lombok; public class User extends AbstractSequenceEntity { private static final long serialVersionUID = 1487903039867324395L; private String username; public String getUsername() { return this.username; } public void setUsername(String username) { this.username = username; } public String toString() { return "User(super=" + super.toString() + ", username=" + getUsername() + ")"; } public boolean equals(Object o) { if (o == this) { return true; } if (!(o instanceof User)) { return false; } User other = (User)o; if (!other.canEqual(this)) { return false; } if (!super.equals(o)) { return false; } Object this$username = getUsername();Object other$username = other.getUsername();return this$username == null ? other$username == null : this$username.equals(other$username); } protected boolean canEqual(Object other) { return other instanceof User; } public int hashCode() { int PRIME = 59;int result = super.hashCode();Object $username = getUsername();result = result * 59 + ($username == null ? 43 : $username.hashCode());return result; } }
4.@Slf4j可以整合日志
原来我们使用日志的方式如下：
package cn.qlq.lombok; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class User { private static final Logger log = LoggerFactory.getLogger(User.class); }
注解方式如下：
package cn.qlq.lombok; import lombok.extern.slf4j.Slf4j; @Slf4j public class User { }
反编译查看：
package cn.qlq.lombok; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class User { private static final Logger log = LoggerFactory.getLogger(User.class); }
5.@Builder用于生成加个构造者模式
package cn.qlq.lombok; import lombok.Builder; import lombok.Data; @Data @Builder public class User { private long id; private String username; }
测试代码：
package cn.qlq.lombok; public class Client { public static void main(String[] args) { // 两种方式创建Builder // UserBuilder builder = User.builder(); User.UserBuilder userBuilder = new User.UserBuilder(); User user = userBuilder.id(5).username("admin").build(); System.out.println(user); } }
结果：
User(id=5, username=admin)
反编译查看：(User$UserBuilder.class是内部类编译后生成的cass文件)
package cn.qlq.lombok; public class User { private long id; private String username; public String toString() { return "User(id=" + getId() + ", username=" + getUsername() + ")"; } public int hashCode() { int PRIME = 59;int result = 1;long $id = getId();result = result * 59 + (int)($id ^ $id >>> 32);Object $username = getUsername();result = result * 59 + ($username == null ? 43 : $username.hashCode());return result; } protected boolean canEqual(Object other) { return other instanceof User; } public boolean equals(Object o) { if (o == this) { return true; } if (!(o instanceof User)) { return false; } User other = (User)o; if (!other.canEqual(this)) { return false; } if (getId() != other.getId()) { return false; } Object this$username = getUsername();Object other$username = other.getUsername();return this$username == null ? other$username == null : this$username.equals(other$username); } public void setUsername(String username) { this.username = username; } public void setId(long id) { this.id = id; } public String getUsername() { return this.username; } public long getId() { return this.id; } public static class UserBuilder { private long id; private String username; public String toString() { return "User.UserBuilder(id=" + this.id + ", username=" + this.username + ")"; } public User build() { return new User(this.id, this.username); } public UserBuilder username(String username) { this.username = username;return this; } public UserBuilder id(long id) { this.id = id;return this; } } public static UserBuilder builder() { return new UserBuilder(); } User(long id, String username) { this.id = id;this.username = username; } }
package cn.qlq.lombok; public class User$UserBuilder { private long id; private String username; public String toString() { return "User.UserBuilder(id=" + this.id + ", username=" + this.username + ")"; } public User build() { return new User(this.id, this.username); } public UserBuilder username(String username) { this.username = username;return this; } public UserBuilder id(long id) { this.id = id;return this; } }
补充一些其他不常用的注解：
@Cleanup : 可以关闭流
@Synchronized ： 加个同步锁
@SneakyThrows : 等同于try/catch 捕获异常
@NonNull : 如果给参数加个这个注解 参数为null会抛出空指针异常
@Value : 注解和@Data类似，区别在于它会把所有成员变量默认定义为private final修饰，并且不会生成set方法。