java - 无法构建 MockMvc(已经映射了 X 类型的处理程序)

我有简单的 Controller 类:

@Controller
public class UserController {
    @RequestMapping("/user")
    @ResponseBody
    @PostAuthorize("hasPermission(returnObject, 'VIEW')")
    public User getUser(Long id) {
        // fetch user from DB
    }
}

我想使用 Spring Security 对我的 Controller 进行集成测试。基于 this article 我创建了以下测试:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(loader = AnnotationConfigWebContextLoader.class, classes = WebappConfig.class)
@WebAppConfiguration
public class UserControllerTest {
    @Autowired
    private WebApplicationContext context;

    @Autowired
    private Filter springSecurityFilterChain;

    protected MockMvc mvc;

    @Before
    public void initializeMvc() {
        mvc = MockMvcBuilders
                .webAppContextSetup(context)
                .addFilters(springSecurityFilterChain)
                .build();
    }

    // tests
}

但是，在 @Before 方法内部，当调用 build() 时，会抛出以下异常:

java.lang.IllegalStateException:
Cannot map handler 'userController' to URL path [/user]:
There is already handler of type
[class com.example.UserController$$EnhancerBySpringCGLIB$$adfe5ea8] mapped.

似乎 Spring 试图将 Controller 实例化两次。为什么？

网络应用配置:

@Configuration
@EnableWebMvc
@ComponentScan("com.example")
@EnableGlobalMethodSecurity(prePostEnabled = true)
@EnableSpringDataWebSupport
public class WebappConfig extends WebMvcConfigurerAdapter { }

完整的堆栈跟踪:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping': Initialization of bean failed; nested exception is java.lang.IllegalStateException: Cannot map handler 'userController' to URL path [/user]: There is already handler of type [class com.example.rest.controller.UserController$$EnhancerBySpringCGLIB$$adfe5ea8] mapped.
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:547) ~[spring-beans-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476) ~[spring-beans-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:291) ~[spring-beans-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.createDefaultStrategy(DispatcherServlet.java:849) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.getDefaultStrategies(DispatcherServlet.java:818) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.initHandlerMappings(DispatcherServlet.java:588) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.initStrategies(DispatcherServlet.java:482) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.onRefresh(DispatcherServlet.java:471) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:555) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:489) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136) [spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at javax.servlet.GenericServlet.init(GenericServlet.java:244) [javax.servlet-api-3.1.0.jar:3.1.0]
    at org.springframework.test.web.servlet.MockMvcBuilderSupport.createMockMvc(MockMvcBuilderSupport.java:52) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.test.web.servlet.setup.AbstractMockMvcBuilder.build(AbstractMockMvcBuilder.java:146) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at com.example.UserControllerTest.initializeMvc(UserControllerTest .java:40) [test/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) [junit-4.12.jar:4.12]
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) [junit-4.12.jar:4.12]
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) [junit-4.12.jar:4.12]
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:73) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:55) [junit-4.12.jar:4.12]
    at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:55) [junit-4.12.jar:4.12]
    at org.junit.rules.RunRules.evaluate(RunRules.java:20) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:73) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:224) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:83) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:68) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:163) [spring-test-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137) [junit-4.12.jar:4.12]
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:78) [junit-rt.jar:na]
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:212) [junit-rt.jar:na]
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:68) [junit-rt.jar:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140) [idea_rt.jar:na]
Caused by: java.lang.IllegalStateException: Cannot map handler 'userController' to URL path [/user]: There is already handler of type [class com.example.rest.controller.UserController$$EnhancerBySpringCGLIB$$adfe5ea8] mapped.
    at org.springframework.web.servlet.handler.AbstractUrlHandlerMapping.registerHandler(AbstractUrlHandlerMapping.java:295) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.handler.AbstractUrlHandlerMapping.registerHandler(AbstractUrlHandlerMapping.java:265) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.handler.AbstractDetectingUrlHandlerMapping.detectHandlers(AbstractDetectingUrlHandlerMapping.java:82) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.handler.AbstractDetectingUrlHandlerMapping.initApplicationContext(AbstractDetectingUrlHandlerMapping.java:58) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.context.support.ApplicationObjectSupport.initApplicationContext(ApplicationObjectSupport.java:120) ~[spring-context-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.context.support.WebApplicationObjectSupport.initApplicationContext(WebApplicationObjectSupport.java:76) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.context.support.ApplicationObjectSupport.setApplicationContext(ApplicationObjectSupport.java:74) ~[spring-context-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.context.support.ApplicationContextAwareProcessor.invokeAwareInterfaces(ApplicationContextAwareProcessor.java:119) ~[spring-context-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.context.support.ApplicationContextAwareProcessor.postProcessBeforeInitialization(ApplicationContextAwareProcessor.java:94) ~[spring-context-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:408) ~[spring-beans-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1566) ~[spring-beans-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539) ~[spring-beans-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    ... 51 common frames omitted

我可以在 MockMvc 独立设置中运行这个测试，但似乎 I can't use spring data web integration then ，这同样令人讨厌。

最佳答案

这是一个假设，因为您没有提供系统的其他部分，这些部分可能看起来不相关，但实际上可能是因为 WebappConfig 类上的 @ComponentScan("com.example") 注释。根据我的经验，这通常是最常见的原因。

如果在包“com.example”或其任何子包中确实有其他@Configuration 类，它们也将被加载到上下文中。

现在如果其他@Configuration 类也有@ComponentScan, 注释，那可能是组件被扫描两次的问题。

因此，如果这是您的情况，则避免这种情况的解决方案是以使用@ComponentScan 注释的类永远不会扫描也使用@ComponentScan 的其他类的方式组织您的包。