java - 为什么模拟注释不模拟/注入(inject)存储库？

Question

我正在使用 mockito 来测试 Controller 。该 Controller 使用连接到数据库的存储库。我想模拟 userRepository 并将其注入(inject)到 usercontroller 中，但是当我运行测试时，在 when(userRepository.addUser(anyString(), anyString())).thenReturn(true); 处抛出 NullPointerException在测试中。此外，当我删除此行以查看 mockMvc 是否也给出此错误时，它确实做到了这一点。

因此我认为问题的根源是 MockitoAnnotations.initMocks(this); 它以某种方式无法启用注释。

我做了一些研究，了解为什么会在 Google 上发生这种情况，但没有一种解决方案可以解决这个问题，而且我不知道为什么这不起作用。

我要测试的 Controller :

@RestController
public class UserController {

    @Autowired
    private transient userRepository userRepository;

    @PostMapping("/user/add")
    public ResponseEntity<?> addUser(@RequestBody User user) {
        String firstname = user.getUsername();
        String lastname = user.getLastName();

        boolean added = userRepository.addUser(firstname , lastname );

        if(added){
            return new ResponseEntity<>(true, HttpStatus.OK);
        }

        return new ResponseEntity<>(HttpStatus.CONFLICT);
    }

到目前为止我的测试:

@RunWith(SpringRunner.class)
class UserControllerTest {

    private MockMvc mockMvc;

    @MockBean
    private UserRepository userRepository;

    @InjectMocks
    private UserController userController;

    @BeforeEach
    public void init() {
        MockitoAnnotations.initMocks(this);
        mockMvc = MockMvcBuilders
                .standaloneSetup(userController)
                .build();
    }

    @Test
    void testAddUserToDb() throws Exception {
        User user = new User();
        User.setFirstName("first");
        User.setLastName("last");

        Gson gson = new Gson();
        String request = gson.toJson(user);

        //HERE I GET NULLPOINTEREXCEPTION
        when(userRepository.addUser(anyString(), anyString())).thenReturn(true);

        mockMvc.perform(post("user/add")
                .contentType(MediaType.APPLICATION_JSON).content(request))
                .andExpect(status().isOk())
                .andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8));


        verify(userRepository, times(1)).addUser(anyString(), anyString());
        verifyNoMoreInteractions(userRepository);
    }

我的用户存储库:

@Repository
public class UserRepository {

    @Autowired
    private transient JdbcTemplate jdbcTemplate;

    public boolean addUser(String firstName, String lastName){
        boolean added = false;

        String ADD_USER = "INSERT INTO Users(firstName, lastname) VALUES(?, ?)";

        //execute sql query and retrieve result set
        int rowsHit = jdbcTemplate.update(ADD_USER, firstName, lastName);

        if (rowsHit == 1) {
            added = true;
        }

        return added;
    }

错误信息:

java.lang.NullPointerException
    at server.controller.UserControllerTest.testAddUserToDb(UserControllerTest.java:21)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:567)
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:436)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:115)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:170)
    at org.junit.jupiter.engine.execution.ThrowableCollector.execute(ThrowableCollector.java:40)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:166)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:113)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:58)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$3(HierarchicalTestExecutor.java:112)
    at org.junit.platform.engine.support.hierarchical.SingleTestExecutor.executeSafely(SingleTestExecutor.java:66)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.executeRecursively(HierarchicalTestExecutor.java:108)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.execute(HierarchicalTestExecutor.java:79)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$2(HierarchicalTestExecutor.java:120)
    at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
    at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
    at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133)
    at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
    at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
    at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
    at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$3(HierarchicalTestExecutor.java:120)
    at org.junit.platform.engine.support.hierarchical.SingleTestExecutor.executeSafely(SingleTestExecutor.java:66)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.executeRecursively(HierarchicalTestExecutor.java:108)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.execute(HierarchicalTestExecutor.java:79)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$2(HierarchicalTestExecutor.java:120)
    at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
    at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
    at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133)
    at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
    at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
    at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
    at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$3(HierarchicalTestExecutor.java:120)
    at org.junit.platform.engine.support.hierarchical.SingleTestExecutor.executeSafely(SingleTestExecutor.java:66)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.executeRecursively(HierarchicalTestExecutor.java:108)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.execute(HierarchicalTestExecutor.java:79)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:55)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:43)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:220)
    at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:188)
    at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:202)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:181)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
    at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:102)
    at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$000(JUnitPlatformTestClassProcessor.java:82)
    at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:78)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:61)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:567)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
    at com.sun.proxy.$Proxy5.stop(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.stop(TestWorker.java:132)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:567)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:164)
    at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:412)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
    at java.base/java.lang.Thread.run(Thread.java:835)

Answer 1

将您的测试类编辑为下面的代码，它不应再抛出任何 NullPointerException(尽管您的代码中还有其他一些编译时错误，例如在 Controller 中混合 firstname 与 用户名)。

@SpringBootTest
@AutoConfigureMockMvc
@RunWith(SpringRunner.class)
public class UserControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Mock
    private UserRepository userRepository;

    @Test
    public void testAddUserToDb() throws Exception {
        User user = new User();
        user.setFirstName("first");
        user.setLastName("last");

        Gson gson = new Gson();
        String request = gson.toJson(user);

        //HERE I GET NULLPOINTEREXCEPTION
        when(userRepository.addUser(anyString(), anyString())).thenReturn(true);

        mockMvc.perform(post("user/add")
                .contentType(MediaType.APPLICATION_JSON).content(request))
                .andExpect(status().isOk())
                .andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8));


        verify(userRepository, times(1)).addUser(anyString(), anyString());
        verifyNoMoreInteractions(userRepository);
    }
}

在您的 gradle 文件中，您混合了 Spring (Boot) 版本和 Spring 的一些其他临时依赖项。您是否也可以将 Gradle 文件更新为:

plugins {
    id 'org.springframework.boot' version '2.2.1.RELEASE'
    id 'io.spring.dependency-management' version '1.0.8.RELEASE'
    id 'java'
}

sourceCompatibility = 12

repositories {
    mavenCentral()
    jcenter()
}

test {
    useJUnitPlatform()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-jdbc'
    implementation 'org.springframework.boot:spring-boot-starter-security'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    implementation group: 'com.google.code.gson', name: 'gson', version: '2.8.5'

    components {
        withModule('org.springframework:spring-beans') {
            allVariants {
                withDependencyConstraints {
                    it.findAll { it.name == 'snakeyaml' }.each { it.version { strictly '1.19' } }
                }
            }
        }
    }
}

bootJar {
    mainClassName = 'server.Application'
}

如果你会得到关于数据源的异常，然后从 Gradle 配置中删除 implementation 'org.springframework.boot:spring-boot-starter-jdbc'(或导入数据源依赖项和如果您使用的是数据库，请在 Gradle 中配置它。