Lombok简单化Java代码　-　Code less do More

2012-10-16

Lombok简化Java代码　-　Code less do More关于Lombok这个东西,论坛里已经有人介绍过,我也是通过别人帖子了

Lombok简化Java代码　-　Code less do More

关于Lombok这个东西,论坛里已经有人介绍过,我也是通过别人帖子了解到这个小工具:

http://www.iteye.com/topic/798305

不过作者以免写Getter/Setter为题来介绍Lombok的优势,看了后面的评论之后,觉得这个工具意义不大.

后来在博客在线看到一篇文章,期中提到了Lombok工具.这个工具已经被国外创业者所使用,随之对其产生了很浓厚的兴趣.

<Java开源建站工具>http://www.jobbole.com/entry.php/1233

关于如何介绍Lombok这个工具,自己想了半天,觉得实在比不过作者在首页提供的视频介绍:

http://projectlombok.org/

ｏｋ~　写了这么多Lombok到底是什么东西,他具体能带来什么便利呢?

Lombok主要是提供一套注解,根据注解在编译时生成相关代码,目前提供如下注解:

@Getter?/?@Setter

永远不用再写?public int getFoo() {return foo;}.

@Getter(lazy=true)

Laziness is a virtue!

@ToString

Ｌombok会根据field自动生成toString?方法,这个对调试来说很方便! 这个注解生成的toString格式:

LombokUser(id=001, name=wity_lv, email=wity_lv@sample.com)?

@EqualsAndHashCode

生成?hashCode?and?equals?方法.

@NoArgsConstructor,?@RequiredArgsConstructor?and?@AllArgsConstructor

Constructors made to order: Generates constructors that take no arguments, one argument per final / non-null field, or one argument for every field.

@Data

All together now: A shortcut for?@ToString,?@EqualsAndHashCode,?@Getter?on all fields, and?@Setter?on all non-final fields, and?@RequiredArgsConstructor!

@Cleanup

Automatic resource management: Call your?close()?methods safely with no hassle.

@Synchronized

synchronized?done right: Don't expose your locks.

@SneakyThrows

To boldly throw checked exceptions where no one has thrown them before!

@Log

支持多种Log工具,　我平时用@Log4j注解

val

Finally! Hassle-free final local variables.

@Delegate

Don't lose your composition.

如何使用?

1. 从项目首页下载lombok.jar

2. 双击lombok.jar, 将其安装到eclipse中(该项目需要jdk1.6+的环境)

Lombok简单化Java代码　-　Code less do More

3.　将Lombok.jar添加到classpath中

4. 　编码看看:

项目结构:

Lombok简单化Java代码　-　Code less do More

package lv.sample.lombok;import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;import lombok.extern.log4j.Log4j;@Data@NoArgsConstructor@AllArgsConstructor@Log4jpublic class LombokUser {private String id = null;private String name = null;private String email = null;public static void main(String[] args) {log.info("test the lombok bean");LombokUser u = new LombokUser("001", "wity_lv", "wity_lv@sample.com");System.out.println(u.toString());LombokUser u2 = new LombokUser("001", "wity_lv", "wity_lv@sample.com");System.out.println(u.equals(u2));}}

?
?console out 写道

在eclipse outline中显示的结构

Lombok简单化Java代码　-　Code less do More

到这里 ~ 这些仅仅只是作者提供一些方便的注释,　当然我们可以fork这个项目的　GitHub, 研究内部原理,构建适合自己团队的Lombok:

https://github.com/rzwitserloot/lombok

2011-08-26 10:00 补充 ?User中究竟省了多少代码:

关于上面写的User方法,我用作者提供的 delombok 进行了反向生成,　看看这些注释究竟省了多少代码:

// Generated by delombok at Fri Aug 26 18:12:13 CST 2011package lv.sample.lombok;public class LombokUser {private String id = null;private String name = null;private String email = null;public static void main(String[] args) {log.info("test the lombok bean");LombokUser u = new LombokUser("001", "wity_lv", "wity_lv@sample.com");log.info(u.toString());LombokUser u2 = new LombokUser("001", "wity_lv", "wity_lv@sample.com");log.info(u.equals(u2));}@java.lang.SuppressWarnings("all")public String getId() {return this.id;}@java.lang.SuppressWarnings("all")public String getName() {return this.name;}@java.lang.SuppressWarnings("all")public String getEmail() {return this.email;}@java.lang.SuppressWarnings("all")public void setId(final String id) {this.id = id;}@java.lang.SuppressWarnings("all")public void setName(final String name) {this.name = name;}@java.lang.SuppressWarnings("all")public void setEmail(final String email) {this.email = email;}@java.lang.Override@java.lang.SuppressWarnings("all")public boolean equals(final java.lang.Object o) {if (o == this) return true;if (!(o instanceof LombokUser)) return false;final LombokUser other = (LombokUser)o;if (!other.canEqual((java.lang.Object)this)) return false;if (this.getId() == null ? other.getId() != null : !this.getId().equals((java.lang.Object)other.getId())) return false;if (this.getName() == null ? other.getName() != null : !this.getName().equals((java.lang.Object)other.getName())) return false;if (this.getEmail() == null ? other.getEmail() != null : !this.getEmail().equals((java.lang.Object)other.getEmail())) return false;return true;}@java.lang.SuppressWarnings("all")public boolean canEqual(final java.lang.Object other) {return other instanceof LombokUser;}@java.lang.Override@java.lang.SuppressWarnings("all")public int hashCode() {final int PRIME = 31;int result = 1;result = result * PRIME + (this.getId() == null ? 0 : this.getId().hashCode());result = result * PRIME + (this.getName() == null ? 0 : this.getName().hashCode());result = result * PRIME + (this.getEmail() == null ? 0 : this.getEmail().hashCode());return result;}@java.lang.Override@java.lang.SuppressWarnings("all")public java.lang.String toString() {return "LombokUser(id=" + this.getId() + ", name=" + this.getName() + ", email=" + this.getEmail() + ")";}@java.lang.SuppressWarnings("all")public LombokUser() {}@java.beans.ConstructorProperties({"id", "name", "email"})@java.lang.SuppressWarnings("all")public LombokUser(final String id, final String name, final String email) {this.id = id;this.name = name;this.email = email;}private static final org.apache.log4j.Logger log = org.apache.log4j.Logger.getLogger(LombokUser.class);}?

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Lombok简单化Java代码 - Code less do More

Lombok简单化Java代码　-　Code less do More