记录MockMvc请求Controller时，Service报空指针异常的问题与解决

2023-11-24 14:12| 来源: 网络整理| 查看: 265

MockMvc请求Controller时，Service报空指针异常问题重现原因分析解决方法其他原因

问题重现

代码结构如下：已通过主函数启动，项目无问题，正常运行。在这里插入图片描述初始代码：

import com.alibaba.fastjson.JSONObject; import com.nancalyy.controller.ModelDataController; import org.junit.Before; import org.junit.Test; import org.junit.runner.RunWith; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc; import org.springframework.http.MediaType; import org.springframework.test.context.junit4.SpringRunner; import org.springframework.test.web.servlet.MockMvc; import org.springframework.test.web.servlet.ResultActions; import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder; import org.springframework.test.web.servlet.request.MockMvcRequestBuilders; import org.springframework.test.web.servlet.result.MockMvcResultHandlers; import org.springframework.test.web.servlet.setup.MockMvcBuilders; @RunWith(SpringRunner.class) @org.springframework.boot.test.context.SpringBootTest(classes = ModelServiceApplication.class) @AutoConfigureMockMvc public class ModelDataControllerTest { private Logger logger = LoggerFactory.getLogger(ModelDataControllerTest.class); private MockMvc mockMvc; @Before public void setUp(){ logger.info("单元测试------初始化执行"); mockMvc = MockMvcBuilders.standaloneSetup(new ModelDataController()).build(); } /** * 数据统计单元测试 * @throws Exception */ @Test public void dataCounterTest() throws Exception { MockHttpServletRequestBuilder requestBuilder = MockMvcRequestBuilders.get("/model/dataCounter") .accept(MediaType.APPLICATION_JSON,MediaType.APPLICATION_JSON_UTF8)//请求数据格式 .contentType(MediaType.APPLICATION_JSON);//接受所用数据格式 // 执行请求 ResultActions result = mockMvc.perform(requestBuilder); //结果解析 result.andDo(MockMvcResultHandlers.print()) // 打印 .andReturn(); // 返回 }

报错：

rg.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:72) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:167) at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:134) at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:183) at com.nancalyy.ModelDataControllerTest.dataCounterTest(ModelDataControllerTest.java:46) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) 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.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) 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$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69) at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38) at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11) at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35) at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235) at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54) Caused by: java.lang.NullPointerException at com.nancalyy.controller.ModelDataController.dataCounter(ModelDataController.java:33) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ... 42 more 原因分析

原因解析：未能注入Service。是由于在单元测试中，使用setup方法初始化测试用例时，使用了new ModelDataController()。该方法就重新建立了一个controller，未使用springboot注入的原controller，因此找不到注入的service。

解决方法

解决方法：采用注入的方式，获取controller实例。代码如下：

import com.alibaba.fastjson.JSONObject; import com.nancalyy.controller.ModelDataController; import org.junit.Before; import org.junit.Test; import org.junit.runner.RunWith; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc; import org.springframework.http.MediaType; import org.springframework.test.context.junit4.SpringRunner; import org.springframework.test.web.servlet.MockMvc; import org.springframework.test.web.servlet.ResultActions; import org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder; import org.springframework.test.web.servlet.request.MockMvcRequestBuilders; import org.springframework.test.web.servlet.result.MockMvcResultHandlers; import org.springframework.test.web.servlet.setup.MockMvcBuilders; @RunWith(SpringRunner.class) @org.springframework.boot.test.context.SpringBootTest(classes = ModelServiceApplication.class) @AutoConfigureMockMvc public class ModelDataControllerTest { private Logger logger = LoggerFactory.getLogger(ModelDataControllerTest.class); private MockMvc mockMvc; @Autowired private ModelDataController modelDataController; @Before public void setUp(){ logger.info("单元测试------初始化执行"); mockMvc = MockMvcBuilders.standaloneSetup(modelDataController).build(); } /** * 数据统计单元测试 * @throws Exception */ @Test public void dataCounterTest() throws Exception { MockHttpServletRequestBuilder requestBuilder = MockMvcRequestBuilders.get("/model/dataCounter") .accept(MediaType.APPLICATION_JSON,MediaType.APPLICATION_JSON_UTF8)//请求数据格式 .contentType(MediaType.APPLICATION_JSON);//接受所用数据格式 // 执行请求 ResultActions result = mockMvc.perform(requestBuilder); //结果解析 result.andDo(MockMvcResultHandlers.print()) // 打印 .andReturn(); // 返回 } 其他原因

该问题其余方法：对于测试用例类，没有添加注解（如下）：

@RunWith(SpringRunner.class) @org.springframework.boot.test.context.SpringBootTest(classes = XXXXApplication.class)

没添加该注解，就不会执行springboot的主函数。

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