spring - @RunWith(SpringJUnit4ClassRunner.class) 无法加载带有 NULL 的 ApplicationContext 'contextLoader'

Question

我有这个代码，

@RunWith(SpringJUnit4ClassRunner.class)
public class JunitDemo {

    @Test
    public void testAssertArrayEquals() {

        byte[] expected = "trial".getBytes();
        byte[] actual = "trial".getBytes();

        Assert.assertArrayEquals("fail", expected, actual);
    }
}

并运行测试，出现错误

Caused by: java.lang.IllegalArgumentException: Can not load an ApplicationContext with a NULL 'contextLoader'. Consider annotating your test class with @ContextConfiguration. at org.springframework.util.Assert.notNull(Assert.java:112) at org.springframework.test.context.TestContext.loadApplicationContext(TestContext.java:276) at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:304) ... 28 more

然后，我找到了与SO相同的Q，解决方案是

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
public class JunitDemo {

    @Resource
    private ApplicationContext ApplicationContext;

    @Test
    public void testAssertArrayEquals() {

        byte[] expected = "trial".getBytes();
        byte[] actual = "trial".getBytes();

        Assert.assertArrayEquals("fail", expected, actual);
    }
}

事实上，对于这个pojo，我不需要xml配置。我会得到其他错误

Caused by: java.io.FileNotFoundException: class path resource [/JunitDemo-context.xml] cannot be opened because it does not exist at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:158) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:328) ... 37 more

如何正确运行我的程序？

Answer 1

来自@ContextConfiguration文档:

@ContextConfiguration defines class-level metadata that is used to determine how to load and configure an ApplicationContext for integration tests.

注释本身具有属性loader并且文档说:

If not specified, the loader will be inherited from the first superclass that is annotated with @ContextConfiguration and specifies an explicit loader. If no class in the hierarchy specifies an explicit loader, a default loader will be used instead.

The default concrete implementation chosen at runtime.

因此您可以指定上下文 loader直接使用 loader 属性。要导航到直接配置，请使用 xml 的 locations 和带注释的类配置的 classes 。

在您的情况下，Spring 选择 GenericXmlContextLoader 进行上下文加载，您没有指定位置，因此 ApplicationConext 将从“classpath:/com/example/<您的_test_class_name>-context.xml”

这是good article关于它。