java - Spring Junit 测试因 NullPointerException 而失败
问题描述
我正在为我的 REST API 端点编写 JUnit,我为此创建了一个简单的 hello world 控制器类和 JUnit,但是在执行 JUnit 测试用例时我遇到了异常。如果有人可以帮助我解决这个问题,那将非常有帮助。我正在使用带有 Spring 4.3 版本的 JDK 6
注意:我没有使用 spring-context XML - 我使用的是 Java 注释
HelloController.java
@RestController
@RequestMapping("/hello")
public class HelloController {
@GetMapping
public String helloWorld() {
return "hello World";
}
}
HelloControllerTest.java
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {HelloController.class})
public class HelloControllerTest {
private MockMvc mockMvc;
@InjectMocks
private HelloController helloController;
@Before
public void setUp() throws Exception {
mockMvc = MockMvcBuilders.standaloneSetup(helloController).build();
}
@Test
public void testHelloWorld() throws Exception {
mockMvc.perform(MockMvcRequestBuilders.get("/hello")).andExpect(MockMvcResultMatchers.status().isOk())
.andExpect(MockMvcResultMatchers.content().string("hello World"));
}
}
例外:
java.lang.NullPointerException
at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.detectHandlerMethods(AbstractHandlerMethodMapping.java:227)
at org.springframework.test.web.servlet.setup.StandaloneMockMvcBuilder$StaticRequestMappingHandlerMapping.registerHandlers(StandaloneMockMvcBuilder.java:486)
at org.springframework.test.web.servlet.setup.StandaloneMockMvcBuilder.registerMvcSingletons(StandaloneMockMvcBuilder.java:352)
at org.springframework.test.web.servlet.setup.StandaloneMockMvcBuilder.initWebAppContext(StandaloneMockMvcBuilder.java:337)
at org.springframework.test.web.servlet.setup.AbstractMockMvcBuilder.build(AbstractMockMvcBuilder.java:139)
at HelloControllerTest.setUp(HelloControllerTest.java:32)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:60)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
at java.lang.reflect.Method.invoke(Method.java:611)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
解决方案
如果您使用的是standaloneSetup
,则无需使用SpringJUnit4ClassRunner
. 那个跑步者需要一个 Spring 配置。
你可以HelloController
自己初始化一个
例如
public class HelloControllerTest {
private MockMvc mockMvc;
private HelloController helloController = new HelloController();
@Before
public void setUp() throws Exception {
mockMvc = MockMvcBuilders.standaloneSetup(helloController).build();
}
@Test
public void testHelloWorld() throws Exception {
mockMvc.perform(MockMvcRequestBuilders.get("/hello")).andExpect(MockMvcResultMatchers.status().isOk())
.andExpect(MockMvcResultMatchers.content().string("hello World"));
}
或者您可以让 Spring 通过注入您的 WebApplicationContext 并使用创建 WebApplicationContext 所需的任何配置来构建它
@RunWith(SpringRunner.class)
@ContextConfiguration(classes = MyWebApplicationConfig.class)
public class HelloControllerTest {
@Autowired
private WebApplicationContext wac;
private MockMvc mockMvc;
private HelloController helloController;
@Before
public void setUp() throws Exception {
mockMvc = MockMvcBuilders.webAppContextSetup(wac).build();
}
或者最后,如果你碰巧使用 Spring Boot,你可以使用他们的 Slice Test 注释之一,
@RunWith(SpringRunner.class)
@WebMvcTest
public class HelloControllerTest {
@Autowired
private MockMvc mockmvc;
}
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