标签:size prime mpi public creat intellij 使用 static 返回
这里对lombok的@Builder和@Data组合的使用示例
import lombok.Builder; import lombok.Data; @Data @Builder public class People { private String name; private String sex; private int age; }
@Test public void testBuilderAnnotation(){ People.PeopleBuilder builder = People.builder(); People.PeopleBuilder peopleBuilder = builder.name("LuoTianyan").age(23); if(true){ peopleBuilder.sex("female"); } People luoTianyan = peopleBuilder.build(); System.out.println(luoTianyan.toString()); //People(name=LuoTianyan, sex=female, age=23) People people = new People("LuoTianyan","female",23); System.out.println(luoTianyan.equals(people)); //true }
class People加上了@Builder和@Data注解后,多了一个静态内部类PeopleBuilder,People调用静态方法builder生成PeopleBuilder对象,PeopleBuilder可以使用".属性名(属性值)"的方式进行属性设置,再调用build()方法就生成了People对象,并且如果两个对象的属性如果相同,就会认为这两个对象相等,即重写了hashCode和equls方法。
在Intellij IDEA下,查看反编译的文件People.class;
可以看到,生成的有:
Getter和Setter方法;
访问类型是private无参构造方法,访问类型为defaul的全部参数的构造方法;
重写hashCode、equals、toString方法,则People可以做为Map的key;
访问类型为public的静态方法builder,返回的是People.PeopleBuilder对象,非单例;
访问类型为public的静态内部类PeopleBuilder,该类主要有build方法,返回类型是People;
最后还有个canEqual方法,判断是否与People同类型。
// // Source code recreated from a .class file by IntelliJ IDEA // (powered by Fernflower decompiler) // public class People { private String name; private String sex; private int age; People(String name, String sex, int age) { this.name = name; this.sex = sex; this.age = age; } public static People.PeopleBuilder builder() { return new People.PeopleBuilder(); } private People() { } public String getName() { return this.name; } public String getSex() { return this.sex; } public int getAge() { return this.age; } public void setName(String name) { this.name = name; } public void setSex(String sex) { this.sex = sex; } public void setAge(int age) { this.age = age; } public boolean equals(Object o) { if (o == this) { return true; } else if (!(o instanceof People)) { return false; } else { People other = (People)o; if (!other.canEqual(this)) { return false; } else { label39: { Object this$name = this.getName(); Object other$name = other.getName(); if (this$name == null) { if (other$name == null) { break label39; } } else if (this$name.equals(other$name)) { break label39; } return false; } Object this$sex = this.getSex(); Object other$sex = other.getSex(); if (this$sex == null) { if (other$sex != null) { return false; } } else if (!this$sex.equals(other$sex)) { return false; } if (this.getAge() != other.getAge()) { return false; } else { return true; } } } } protected boolean canEqual(Object other) { return other instanceof People; } public int hashCode() { int PRIME = true; int result = 1; Object $name = this.getName(); int result = result * 59 + ($name == null ? 43 : $name.hashCode()); Object $sex = this.getSex(); result = result * 59 + ($sex == null ? 43 : $sex.hashCode()); result = result * 59 + this.getAge(); return result; } public String toString() { return "People(name=" + this.getName() + ", sex=" + this.getSex() + ", age=" + this.getAge() + ")"; } public static class PeopleBuilder { private String name; private String sex; private int age; PeopleBuilder() { } public People.PeopleBuilder name(String name) { this.name = name; return this; } public People.PeopleBuilder sex(String sex) { this.sex = sex; return this; } public People.PeopleBuilder age(int age) { this.age = age; return this; } public People build() { return new People(this.name, this.sex, this.age); } public String toString() { return "People.PeopleBuilder(name=" + this.name + ", sex=" + this.sex + ", age=" + this.age + ")"; } } }
标签:size prime mpi public creat intellij 使用 static 返回
原文地址:https://www.cnblogs.com/theRhyme/p/10181103.html