使用lombok从现有对象构建对象 [英] Build an object from an existing one using lombok
问题描述
假设我有一个lombok注释类,如
Lets say I have a lombok annotated class like
@Builder
class Band {
String name;
String type;
}
我知道我能做到:
Band rollingStones = Band.builder().name("Rolling Stones").type("Rock Band").build();
是否有一种简单的方法可以使用现有对象作为模板创建Foo对象并更改一个它的属性?
Is there an easy way to create an object of Foo using the existing object as a template and changing one of it's properties?
类似于:
Band nirvana = Band.builder(rollingStones).name("Nirvana");
我在lombok文档中找不到这个。
I can't find this in the lombok documentation.
推荐答案
您可以使用 toBuilder
参数为您的实例提供 toBuilder()
方法。
You can use the toBuilder
parameter to give your instances a toBuilder()
method.
@Builder(toBuilder=true)
class Foo {
int x;
...
}
Foo f0 = Foo.builder().build();
Foo f1 = f0.toBuilder().x(42).build();
来自文档:
如果使用@Builder生成构建器来生成自己类的实例(这总是除非将@Builder添加到不返回自己类型的方法中,否则可以使用@Builder(toBuilder = true)在类中生成一个名为toBuilder()的实例方法;它会创建一个以该实例的所有值开头的新构建器。
If using @Builder to generate builders to produce instances of your own class (this is always the case unless adding @Builder to a method that doesn't return your own type), you can use @Builder(toBuilder = true) to also generate an instance method in your class called toBuilder(); it creates a new builder that starts out with all the values of this instance.
免责声明:我是一名lombok开发人员。
Disclaimer: I am a lombok developer.
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