带有 MockMVC 的 Junit - 错误 - java.lang.IllegalArgumentException：实体不能为空答案

【问题标题】：Junit with MockMVC - Error - java.lang.IllegalArgumentException: Entity must not be null带有 MockMVC 的 Junit - 错误 - java.lang.IllegalArgumentException：实体不能为空
【发布时间】：2020-02-27 21:17:26
【问题描述】：

我为书店创建了一个简单的 get 和 post rest 服务。我是 Junit 的新手。使用 Mockito 后调用时出现错误。

BookRepository.java

public interface BookRepository extends MongoRepository<Book, BigInteger> {

}

BookController.java


@RestController
public class BookController {

    @Autowired
    BookRepository bookRepository;

    @GetMapping("/books")
    public ResponseEntity<List<Book>> get(){
        return new ResponseEntity<List<Book>>(bookRepository.findAll(), HttpStatus.OK);
    }

    @PostMapping("/book")
    public ResponseEntity<Book> create(@RequestBody Book book){
        return new ResponseEntity<Book>(bookRepository.save(book), HttpStatus.CREATED);
    }

}

Book.java

@Document(collection="book")
public class Book {

    @Id
    private BigInteger id;
    private String bookname;
    private String author;
    private BigDecimal price;
    //getter and setter
}

JunitApplicationTests.java

@SpringBootTest
@AutoConfigureMockMvc
class JunitApplicationTests {

    @Autowired
    private MockMvc mockMvc;

    @Autowired
    private BookRepository bookRepository;

    @Test
    public void get() throws Exception {
        mockMvc.perform(MockMvcRequestBuilders.get("/books")).andExpect(MockMvcResultMatchers.status().isOk());
    }

    @Test
    public void create() throws Exception{
        Book book=createBook();
        Mockito.when(bookRepository.save(Mockito.any(Book.class))).thenReturn(book);//here I am getting error
        mockMvc.perform(MockMvcRequestBuilders.post("/book")).andExpect(MockMvcResultMatchers.status().isCreated());
    }

    public Book createBook() {
        Book book=new Book();
        book.setId(new BigInteger("102"));
        book.setBookname("Java Concept");
        book.setAuthor("James K");
        book.setPrice(new BigDecimal("205.50"));
        return book;
    }
}

我遇到了错误

java.lang.IllegalArgumentException: Entity must not be null!
    at org.springframework.util.Assert.notNull(Assert.java:198)
    at org.springframework.data.mongodb.repository.support.SimpleMongoRepository.save(SimpleMongoRepository.java:81)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:371)
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:204)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:657)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:621)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:605)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:95)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
    at com.sun.proxy.$Proxy82.save(Unknown Source)
    at com.example.demo.JunitApplicationTests.create(JunitApplicationTests.java:33)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:675)
    at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:125)
    at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:132)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:124)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:74)
    at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:104)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:62)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:43)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:35)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:202)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:198)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:135)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:69)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:135)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
    at java.util.ArrayList.forEach(Unknown Source)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
    at java.util.ArrayList.forEach(Unknown Source)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:220)
    at org.junit.platform.launcher.core.DefaultLauncher.lambda$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.eclipse.jdt.internal.junit5.runner.JUnit5TestReference.run(JUnit5TestReference.java:89)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)

我为书店创建了一个简单的 get 和 post rest 服务。我是 Junit 的新手。使用 Mockito 后调用时出现错误。

【问题讨论】：

你用@AutowiredBookRepository，我觉得应该是@MockBean吧？
感谢您的建议。有效。但是当我执行 Junit 测试用例时，create book 测试实际上是在数据库中创建记录。我认为不应该。你能建议吗？
如果你在 bookRepository 字段上使用了@MockBean 注解，它不应该在数据库中创建任何记录，因为它不会调用它的实际 save() 方法。您能否分享一段导致记录直接进入数据库的测试代码？
我用@Mock代替@MockBean，它正在数据库中创建记录，现在我使用@MockBean，并且记录没有创建。但我很惊讶为什么@Mock 正在创建记录而@MockBean 不是，两者有什么区别。
当项目不是带有 SpringBootTests 的 SpringBoot 项目时，我会使用 @Mock :) 这里很好地解释了它们的不同之处：stackoverflow.com/questions/44200720/…

标签： java junit mockito mockmvc

【解决方案1】：

测试中的问题create()。你正在做没有身体的帖子。添加.content()和.contentType()：

mockMvc.perform(MockMvcRequestBuilders.post("/book"))
   .contentType(MediaType.APPLICATION_JSON_UTF8)
   .content(bookJson)
   .andExpect(MockMvcResultMatchers.status().isCreated());

【讨论】：

好东西要指出，但这不是问题。如果是这样，它会抛出 400（错误请求）而不是 NPE :) NPE 发生是因为 BookRepository 是自动装配的而不是模拟的。所以， save() 方法是一个实际的调用。 Spring 断言实体为 null 并做出相应反应，因为 any(Book.class) 将返回 null。