Java自定义注解聚合多个注解

问题描述

我正在为我的 RestControllers
编写一个 TestCases对于每个 ControllerTest calss 我使用以下注释

Im writing a TestCases for my RestControllers
For each ControllerTest calss I use the following annotations

@WebAppConfiguration
@RunWith(value = SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {WebConfig.class, TestAppConfig.class})

所以，我决定定义我自己的注释女巫，包含所有这样的注释

So, I decided to define my own annotation witch contain all those annotations like this

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@WebAppConfiguration
@RunWith(value = SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {WebConfig.class, TestAppConfig.class})
public @interface ControllerTest {
}

然后，我只对所有 ControllerTest 类

@ControllerTest
public class XXControllerTest {
}

此修改后测试失败

java.lang.IllegalArgumentException: WebApplicationContext is required
    at org.springframework.util.Assert.notNull(Assert.java:115)

为了让它再次工作，我需要将 @RunWith(SpringJUnit4ClassRunner.class) 添加到 Test class

And to make it work again it required me to add the @RunWith(SpringJUnit4ClassRunner.class) to the Test class

@ControllerTest
@RunWith(SpringJUnit4ClassRunner.class)
public class XXControllerTest {
}

我的问题是为什么我的 @ControllerTest 注释在包含 @RunWith(SpringJUnit4ClassRunner.class) 注释时不起作用?@RunWith 注释有什么特别之处吗?还是我错过了什么?

My question is why my @ControllerTest annotation doesn't work while its contain the @RunWith(SpringJUnit4ClassRunner.class) annotation? is there anything special about the @RunWith annotation? or did I miss something?

PS:我对 Spring 配置类 使用相同的方法，它们工作得很好.

PS: I use the same approach for Spring config classes and they work just fine.

推荐答案

这种机制，您可以拥有元注释"，这些注释本身与其他注释一起注释，然后应用于您放置元注释的类注解，是特定于 Spring 框架的东西.它不是 Java 注释的标准特性.

This mechanism, where you can have "meta-annotations" that are themselves annotated with other annotations, which then apply to the class on which you put your meta-annotation, is something that is specific to the Spring Framework. It is not a standard feature of Java annotations.

它不起作用，因为 JUnit 不了解这种机制.@RunWith 注释是一个 JUnit 注释.JUnit 不明白它应该查看 @ControllerTest 元注释上的注释.

It doesn't work because JUnit does not understand this mechanism. The @RunWith annotation is a JUnit annotation. JUnit does not understand that it should look at the annotations that are on your @ControllerTest meta-annotation.

因此，此机制适用于由 Spring 处理的注释，但不适用于由其他工具(如 JUnit)处理的注释.

So, this mechanism works with annotations that are processed by Spring, but not with annotations that are processed by other tools such as JUnit.

这篇关于Java自定义注解聚合多个注解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！