lombok使用-简介
2017-03-21 09:41
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lombok使用
lombok的使用简介
lombok其实就是在我们进行编译事加一层处理的机制,具体百度。* https://projectlombok.org/features/index.html
* http://lrwinx.github.io/2017/03/04/%E7%BB%86%E6%80%9D%E6%9E%81%E6%81%90-%E4%BD%A0%E7%9C%9F%E7%9A%84%E4%BC%9A%E5%86%99java%E5%90%97/ 这个小哥写的不错
* http://tech.meituan.com/clean-code.html cleancode
* http://www.zuidaima.com/share/1949333085654016.htm lombok使用
常用注解
@Data :注解在类上;提供类所有属性的 getting 和 setting 方法,此外还提供了equals、canEqual、hashCode、toString 方法@Setter:注解在属性上;为属性提供 setting 方法
@Getter:注解在属性上;为属性提供 getting 方法
@Log4j :注解在类上;为类提供一个 属性名为log 的 log4j 日志对象
@Slf4j : 注解在类上;为类提供一个 属性名为log 的 log4j 日志对象
@NoArgsConstructor:注解在类上;为类提供一个无参的构造方法
@AllArgsConstructor:注解在类上;为类提供一个全参的构造方法
@Accessors(chain = true) 支持链式调用的:
@Builder 建筑者模式
实战
Getter,Setter
import lombok.Getter; import lombok.Setter; import lombok.extern.slf4j.Slf4j; @Slf4j @Getter @Setter public class Person { private String name; private String old; public static void main(String[] args) { Person px =new Person(); px.setName("xx"); px.setOld("xx"); log.info(px.getName()); } }
编译后的代码:
import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class Person { private static final Logger log = LoggerFactory.getLogger(Person.class); private String name; private String old; public Person() { } public static void main(String[] args) { Person px = new Person(); px.setName("xx"); px.setOld("xx"); log.info(px.getName()); } public String getName() { return this.name; } public String getOld() { return this.old; } public void setName(String name) { this.name = name; } public void setOld(String old) { this.old = old; } }
@Data
编译前:import lombok.Data; import lombok.extern.slf4j.Slf4j; /** * Created by wangji on 2017/3/20. */ @Slf4j @Data public class Person { private String name; private String old; public static void main(String[] args) { Person px =new Person(); px.setName("xx"); px.setOld("xx"); log.info(px.getName()); } }
编译后的结果,可以看到给予了许多的get,set and toString等等
import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class Person { private static final Logger log = LoggerFactory.getLogger(Person.class); private String name; private String old; public static void main(String[] args) { Person px = new Person(); px.setName("xx"); px.setOld("xx"); log.info(px.getName()); } public Person() { } public String getName() { return this.name; } public String getOld() { return this.old; } public void setName(String name) { this.name = name; } public void setOld(String old) { this.old = old; } public boolean equals(Object o) { if(o == this) { return true; } else if(!(o instanceof Person)) { return false; } else { Person other = (Person)o; if(!other.canEqual(this)) { return false; } else { String this$name = this.getName(); String other$name = other.getName(); if(this$name == null) { if(other$name != null) { return false; } } else if(!this$name.equals(other$name)) { return false; } String this$old = this.getOld(); String other$old = other.getOld(); if(this$old == null) { if(other$old != null) { return false; } } else if(!this$old.equals(other$old)) { return false; } return true; } } } protected boolean canEqual(Object other) { return other instanceof Person; } public int hashCode() { boolean PRIME = true; byte result = 1; String $name = this.getName(); int result1 = result * 59 + ($name == null?43:$name.hashCode()); String $old = this.getOld(); result1 = result1 * 59 + ($old == null?43:$old.hashCode()); return result1; } public String toString() { return "Person(name=" + this.getName() + ", old=" + this.getOld() + ")"; } }
支持链式调用 @Data @Accessors(chain = true) 配合使用
类似这种类型:Student student = new Student() .setAge(24) .setName("zs");
编译前:
import lombok.Data; import lombok.experimental.Accessors; import lombok.extern.slf4j.Slf4j; /** * Created by wangji on 2017/3/20. */ @Slf4j @Data @Accessors(chain = true) public class Person { private String name; private String old; public static void main(String[] args) { Person px =new Person().setOld("xxx").setName("xxx"); log.info(px.getName()); } }
编译后的代码:
import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class Person { private static final Logger log = LoggerFactory.getLogger(Person.class); private String name; private String old; public static void main(String[] args) { Person px = (new Person()).setOld("xxx").setName("xxx"); log.info(px.getName()); } public Person() { } public String getName() { return this.name; } public String getOld() { return this.old; } public Person setName(String name) { this.name = name; return this; } public Person setOld(String old) { this.old = old; return this; } public boolean equals(Object o) { if(o == this) { return true; } else if(!(o instanceof Person)) { return false; } else { Person other = (Person)o; if(!other.canEqual(this)) { return false; } else { String this$name = this.getName(); String other$name = other.getName(); if(this$name == null) { if(other$name != null) { return false; } } else if(!this$name.equals(other$name)) { return false; } String this$old = this.getOld(); String other$old = other.getOld(); if(this$old == null) { if(other$old != null) { return false; } } else if(!this$old.equals(other$old)) { return false; } return true; } } } protected boolean canEqual(Object other) { return other instanceof Person; } public int hashCode() { boolean PRIME = true; byte result = 1; String $name = this.getName(); int result1 = result * 59 + ($name == null?43:$name.hashCode()); String $old = this.getOld(); result1 = result1 * 59 + ($old == null?43:$old.hashCode()); return result1; } public String toString() { return "Person(name=" + this.getName() + ", old=" + this.getOld() + ")"; } }
@builder
Builder模式,可以看一下《Head First》(设计模式) 的建造者模式。一种变种的builder模式,那就是构建bean的builder模式,其实主要的思想是带着大家一起看一下lombok给我们带来了什么。
看一下Student这个类的原始builder状态:
public class Student { private String name; private int age; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public static Builder builder(){ return new Builder(); } public static class Builder{ private String name; private int age; public Builder name(String name){ this.name = name; return this; } public Builder age(int age){ this.age = age; return this; } public Student build(){ Student student = new Student(); student.setAge(age); student.setName(name); return student; } } }
调用的方法:
Student student = Student.builder().name("zs").age(24).build();
这样的builder代码,让我是在恶心难受,于是我打算用lombok重构这段代码:
@Builder public class Student { private String name; private int age; } Student student = Student.builder().name("zs").age(24).build();
上面的是参考的,下面是自己实现的
import lombok.Builder; import lombok.ToString; import lombok.extern.slf4j.Slf4j; /** * Created by wangji on 2017/3/20. */ @Slf4j @Builder @ToString public class Person { private String name; private String old; public static void main(String[] args) { Person person =Person.builder().name("xxx").old("xx").build(); log.info(person.toString()); } }
编译后的代码:
import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class Person { private static final Logger log = LoggerFactory.getLogger(Person.class); private String name; private String old; public static void main(String[] args) { Person person = builder().name("xxx").old("xx").build(); log.info(person.toString()); } Person(String name, String old) { this.name = name; this.old = old; } public static Person.PersonBuilder builder() { return new Person.PersonBuilder(); } public String toString() { return "Person(name=" + this.name + ", old=" + this.old + ")"; } public static class PersonBuilder { private String name; private String old; PersonBuilder() { } public Person.PersonBuilder name(String name) { this.name = name; return this; } public Person.PersonBuilder old(String old) { this.old = old; return this; } public Person build() { return new Person(this.name, this.old); } public String toString() { return "Person.PersonBuilder(name=" + this.name + ", old=" + this.old + ")"; } } }
@NoArgsConstructor:注解在类上;为类提供一个无参的构造方法 @AllArgsConstructor:注解在类上;为类提供一个全参的构造方法
这个没啥好说的!每天都是学习!哈哈!
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