Guice的@Singleton注释可以继承吗? [英] Can Guice's @Singleton annotation be inherited?
本文介绍了Guice的@Singleton注释可以继承吗?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
比方说我有这个课程:
@Singleton
public class Parent { ... }
和此类:
public class Child extends Parent { ... }
在我的Java应用程序中,我的应用程序依靠 Guice 注入来创建对象。如果通过 Injector.createInstance(Child.class)
创建 Child
的实例,该实例将自动成为Singleton (因为父级被注释为Singleton),或者我需要将 @Singleton
注释显式添加到 Child
?
in my Java app, and my app relies on Guice injection to create objects. If I create an instance of Child
through Injector.createInstance(Child.class)
, wiill that instance be a Singleton automatically (because the parent was annotated as a Singleton), or do I need to explicitly add the @Singleton
annotation to Child
?
推荐答案
不是-您还需要注释 Child
。您可以设置一个简单的测试来验证这一点,例如:
Nope - you'd need to annotate Child
as well. You can set up a simple test to verify this like:
public class GuiceTest {
@Singleton
static class Parent {}
static class Child extends Parent{}
static class Module extends AbstractModule {
@Override
protected void configure() {
bind(Parent.class);
bind(Child.class);
}
}
@Test
public void testSingleton() {
Injector i = Guice.createInjector(new Module());
assertNotSame(i.getInstance(Child.class), i.getInstance(Child.class));
}
}
这篇关于Guice的@Singleton注释可以继承吗?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文