Java Spring MVC - java.lang.NoClassDefFoundError: javax/servlet/ServletContext

Question

我正在尝试为我的 Java Spring 应用程序编写一些 JUnit 测试，但我不断收到此错误 java.lang.NoClassDefFoundError: javax/servlet/ServletContext。
测试类：

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = AppConfig.class, loader = AnnotationConfigContextLoader.class)

public class SampleTest {
    @Autowired
    public ApplicationContext applicationContext;

    @Test
    public void sampleTest() throws Exception {
        fail("this is a fail.");
    }

}

pom.xml：

 <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.0.1</version>
        <scope>provided</scope>
 </dependency>
 <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>4.1.7.RELEASE</version>
 </dependency>

AppConfig.java

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = {"my.base.package"})
public class AppConfig extends WebMvcConfigurerAdapter {
    @Bean
    public InternalResourceViewResolver viewResolver() {
        InternalResourceViewResolver res = new InternalResourceViewResolver();
        res.setPrefix("/");
        res.setSuffix(".jsp");
        return res;
    }

    @Bean
    public MessageSource messageSource() {
        ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
        messageSource.setBasename("/i18/usermsg");
        messageSource.setDefaultEncoding("UTF-8");
        return messageSource;
    }

    @Bean
    public LocaleResolver localeResolver() {
        CookieLocaleResolver resolver = new CookieLocaleResolver();
        resolver.setDefaultLocale(new Locale("en_US"));
        resolver.setCookieName("myLocaleCookie");
        resolver.setCookieMaxAge(4800);
        return resolver;
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        LocaleChangeInterceptor interceptor = new LocaleChangeInterceptor();
        interceptor.setParamName("mylocale");
        registry.addInterceptor(interceptor);
    }
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
    configurer.enable();
    }
}

异常跟踪：

java.lang.NoClassDefFoundError: javax/servlet/ServletContext
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2442)
    at java.lang.Class.getDeclaredMethods(Class.java:1808)
    at org.springframework.core.type.StandardAnnotationMetadata.getAnnotatedMethods(StandardAnnotationMetadata.java:140)
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:290)
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:230)
    at org.springframework.context.annotation.ConfigurationClassParser.processImports(ConfigurationClassParser.java:486)
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:276)
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:230)
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:197)
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:166)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:306)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:239)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:254)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:94)
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:606)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:462)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:125)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60)
    at org.springframework.test.context.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:68)
    at org.springframework.test.context.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:86)
    at org.springframework.test.context.DefaultTestContext.getApplicationContext(DefaultTestContext.java:72)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:212)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:200)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:259)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:261)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:219)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:83)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:68)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:163)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:74)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:211)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:67)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
Caused by: java.lang.ClassNotFoundException: javax.servlet.ServletContext
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 49 more

这是我第一次编写 JUnit 测试，所以我不知道你们这些超级好心的人是否需要额外的信息。如果是这样，我很乐意提供他们:)

Answer 1

你需要在你的测试类中使用@WebAppConfiguration注解。 documentation 声明如下：

@WebAppConfiguration 一个类级别的注解，用于声明 为集成测试加载的 ApplicationContext 应该是 Web 应用程序上下文。 @WebAppConfiguration 仅存在于 测试类确保将为 测试，使用路径的默认值“file:src/main/webapp” 到 Web 应用程序的根目录（即资源基础路径）。这 资源基本路径在幕后用于创建一个 MockServletContext 用作测试的 ServletContext WebApplicationContext。

这适用于javax.servlet-api 的provided 范围。

此外，您不能在用于测试的配置类中使用@EnableWebMvc。最好创建一个单独的配置类，它只用于测试，没有@EnableWebMvc。你可以看看这个讨论：java.lang.IllegalArgumentException: A ServletContext is required to configure default servlet handling

Answer 2

它应归功于您在此处声明的范围（提供）的价值。尝试修改它以进行测试，它应该可以正常工作。但建议保持提供，因为此 jar 文件默认由 servlet 容器提供。