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[英]NullPointerException in Spring Boot Autowired service
[英]Spring boot Autowired Service and Repository throwing nullpointerexception
我正在测试一个简单的初学者春季启动应用程序,但它不断为我的服务类和我的存储库类抛出NullPointerException
。
这是我的控制器类:
@EnableAutoConfiguration
@RestController
public class MyController {
@Autowired
private MyService service;
@GetMapping("/welcome")
public String home throws IOException {
return service.getEntities();
}
}
这是Service类:
@EnableAutoConfiguration
@Service
public class MyService{
@Autowired(required=true)
private MyRepository repository;
public MyService() {
};
public List<Entity> getEntities() throws IOException {
return repository.findAll();
}
这是存储库:
@Repository
public interface MyRepository extends JpaRepository<Entity, Long>{
List<Entity> findAll();
}
所以,如果我运行应用程序一切正常。 问题是当我运行此测试时:
@RunWith(SpringRunner.class)
@ContextConfiguration(classes = { MyService.class, MyController.class, Entity.class })
@ComponentScan("test.firstproject")
@EntityScan(basePackages = {"test.firstproject.entities"})
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@AutoConfigureTestDatabase(replace = Replace.NONE)
@EnableJpaRepositories("test.firstproject.repository")
@EnableAutoConfiguration
public class TestController {
private MockMvc mvc = MockMvcBuilders.standaloneSetup(new MyController).build();
public static final MediaType APPLICATION_JSON_UTF8 = new MediaType(MediaType.APPLICATION_JSON.getType(), MediaType.APPLICATION_JSON.getSubtype(), Charset.forName("utf8"));
@Autowired
private ObjectMapper objectMapper;
@Test
public void allEntities() {
this.objectMapper = new ObjectMapper();
try {
ResultActions resultActions = this.mvc
.perform(MockMvcRequestBuilders.get("/welcome").accept(MediaType.APPLICATION_JSON));
this.mvc.perform(get("/welcome")).andExpect(status().isOk());
MvcResult result = resultActions.andReturn();
List<Object> list = objectMapper.readValue(result.getResponse().getContentAsString(), new TypeReference<List<Entity>>(){});
for (Object c : list) {
assertTrue(c.getClass().equals(Entity.class));
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
首先,它在调用service.getEntities()
时抛出了NullPointerException。 然后我尝试初始化服务= new MyService()
,但这次return repository.findAll();
抛出错误。 怎么了?
编辑 - Stacktrace
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1013)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:71)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:166)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:133)
at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:182)
at com.example.demo.TestController.getAllEntities(TestController.java:58)
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:566)
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.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
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:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
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:190)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.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)
Caused by: java.lang.NullPointerException
at com.springmiddleware.controllers.MyController.allEntities(MyController.java:32)
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:566)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
... 40 more
您使用new
in line创建了MyController:
private MockMvc mvc = MockMvcBuilders.standaloneSetup(new MyController()).build();
Spring可能没有为它注入Service
。 尝试autowire:
@Autowired
private MyController myController;
并将MockMvc
实例化移动到@Before
方法:
private MockMvc mvc;
@Before
public void initialize() {
mvc = MockMvcBuilders.standaloneSetup(myController).build();
}
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