Java 使用Mockito测试Spring控制器,空指针异常
我正在尝试使用Mockito测试Spring控制器。我已经模拟了同样使用Java 使用Mockito测试Spring控制器,空指针异常,java,spring,spring-mvc,mocking,mockito,Java,Spring,Spring Mvc,Mocking,Mockito,我正在尝试使用Mockito测试Spring控制器。我已经模拟了同样使用when()的对象,但是我仍然面临空指针异常。请建议解决此异常的方法 链接到的特定行空指针为 modelMap.put("categories", simpleCategoryDAO.getAllCategories()); 我模拟了simpleCategoryDAO,并使用when()返回getAllCategories()的列表 试验方法: @RunWith(MockitoJUnitRunner.class
when()
的对象,但是我仍然面临空指针异常。请建议解决此异常的方法
链接到的特定行空指针为
modelMap.put("categories", simpleCategoryDAO.getAllCategories());
我模拟了simpleCategoryDAO,并使用when()
返回getAllCategories()
的列表
试验方法:
@RunWith(MockitoJUnitRunner.class)
public class CategoryControllerTest {
private MockMvc mockMvc;
@InjectMocks
private CategoryController categoryController;
@Mock
private SimpleCategoryDAO simpleCategoryDAO;
@Before
public void setup() {
categoryController = new CategoryController();
mockMvc = MockMvcBuilders.standaloneSetup(categoryController).build();
}
@Test
public void categories_ShouldRenderCategoriesView() throws Exception {
List<Category> ALL_CATEGORIES = Arrays.asList(
new Category(1,"Funny"),
new Category(2,"JoyFul")
);
Mockito.when(simpleCategoryDAO.getAllCategories()).thenReturn(ALL_CATEGORIES);
mockMvc.perform(get("/categories"))
//.andExpect((MockMvcResultMatchers.model()).attribute("categories",ALL_CATEGORIES));
.andExpect(MockMvcResultMatchers.view().name("categories"));
}
}
例外情况:
java.lang.NullPointerException: null
at com.teja.controller.CategoryController.getAllCategories(CategoryController.java:23) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_73]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_73]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_73]
at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_73]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) ~[spring-web-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137) ~[spring-web-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) ~[spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967) [spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858) [spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) [tomcat-embed-core-8.0.23.jar:8.0.23]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843) [spring-webmvc-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:65) [spring-test-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [tomcat-embed-core-8.0.23.jar:8.0.23]
at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:167) [spring-test-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:134) [spring-test-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:144) [spring-test-4.1.7.RELEASE.jar:4.1.7.RELEASE]
at CategoryControllerTest.categories_ShouldRenderCategoriesView(CategoryControllerTest.java:46) [classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_73]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_73]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_73]
at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_73]
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) [junit-4.12.jar:4.12]
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) [junit-4.12.jar:4.12]
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) [junit-4.12.jar:4.12]
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) [junit-4.12.jar:4.12]
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) [junit-4.12.jar:4.12]
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37) [mockito-core-1.10.19.jar:na]
at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62) [mockito-core-1.10.19.jar:na]
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) [.cp/:na]
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) [.cp/:na]
问题出在实例化新控制器之前的
测试类上
@Before
public void setup() {
categoryController = new CategoryController();
mockMvc = MockMvcBuilders.standaloneSetup(categoryController).build();
}
@Controller
public class CategoryController {
private SimpleCategoryDAO simpleCategoryDAO;
private SimpleGifDAO simpleGifDAO;
@Autowired
public void setSimpleGifDAO(SimpleGifDAO simpleGifDAO) {
this.simpleGifDAO = simpleGifDAO;
}
@Autowired
public void setSimpleCategoryDAO(SimpleCategoryDAO simpleCategoryDAO) {
this.simpleCategoryDAO = simpleCategoryDAO;
}
@RequestMapping("/categories")
public String getAllCategories(ModelMap modelMap) {
modelMap.put("categories", simpleCategoryDAO.getAllCategories());
return "categories";
}
@RequestMapping("/category/{categoryID}")
public String getGifsByCategoryID(@PathVariable int categoryID, ModelMap modelMap) {
modelMap.put("gifs", simpleGifDAO.findGifsByCategoryID(categoryID));
modelMap.put("category", simpleCategoryDAO.getCategoryByID(categoryID));
return "category";
}
}
下面是我如何测试控制器的方法
@RunWith(MockitoJUnitRunner.class)
public class CategoryControllerTest {
private MockMvc mockMvc;
@Mock
private SimpleCategoryDAO simpleCategoryDAO;
@Before
public void setup() {
final CategoryController categoryController = new CategoryController();
//notice here I'm setting the mocked dao here
// if you didn't use @RunWith(MockitoJUnitRunner.class)
// you can do: simpleCategoryDAO = Mockito.mock(SimpleCategoryDAO.class);
categoryController.setSimpleCategoryDAO(simpleCategoryDAO);
mockMvc = MockMvcBuilders.standaloneSetup(categoryController).build();
}
@Test
public void categories_ShouldRenderCategoriesView() throws Exception {
List<Category> ALL_CATEGORIES = Arrays.asList(
new Category(1, "Funny"),
new Category(2, "JoyFul")
);
Mockito.when(simpleCategoryDAO.getAllCategories()).thenReturn(ALL_CATEGORIES);
mockMvc.perform(get("/categories"))
//.andExpect((MockMvcResultMatchers.model()).attribute("categories",ALL_CATEGORIES));
.andExpect(MockMvcResultMatchers.view().name("categories"));
}
}
控制器类:
@Before
public void setup() {
categoryController = new CategoryController();
mockMvc = MockMvcBuilders.standaloneSetup(categoryController).build();
}
@Controller
public class CategoryController {
private SimpleCategoryDAO simpleCategoryDAO;
private SimpleGifDAO simpleGifDAO;
@Autowired
public void setSimpleGifDAO(SimpleGifDAO simpleGifDAO) {
this.simpleGifDAO = simpleGifDAO;
}
@Autowired
public void setSimpleCategoryDAO(SimpleCategoryDAO simpleCategoryDAO) {
this.simpleCategoryDAO = simpleCategoryDAO;
}
@RequestMapping("/categories")
public String getAllCategories(ModelMap modelMap) {
modelMap.put("categories", simpleCategoryDAO.getAllCategories());
return "categories";
}
@RequestMapping("/category/{categoryID}")
public String getGifsByCategoryID(@PathVariable int categoryID, ModelMap modelMap) {
modelMap.put("gifs", simpleGifDAO.findGifsByCategoryID(categoryID));
modelMap.put("category", simpleCategoryDAO.getCategoryByID(categoryID));
return "category";
}
}
注意,我在这里使用的是setter注入,而不是字段注入。您也可以使用构造函数注入(我的首选方式)
在你的测试课上
@RunWith(MockitoJUnitRunner.class)
公共类类别控制器测试{
私有MockMvc-MockMvc;
@嘲弄
私有SimpleCategoryDAO SimpleCategoryDAO;
@以前
公共作废设置(){
最终类别控制器类别控制器=新类别控制器();
//注意,我在这里设置模拟dao
//如果您没有使用@RunWith(MockitoJUnitRunner.class)
//您可以这样做:simpleCategoryDAO=Mockito.mock(simpleCategoryDAO.class);
categoryController.setSimpleCategoryDAO(simpleCategoryDAO);
mockMvc=MockMvcBuilders.standaloneSetup(categoryController.build();
}
@试验
公共无效类别\u ShouldRenderCategoriesView()引发异常{
列出所有类别=数组.asList(
新类别(1,“搞笑”),
新类别(2,“快乐”)
);
Mockito.when(simpleCategoryDAO.getAllCategories())。然后返回(所有类别);
mockMvc.perform(get(“/categories”))
//.andExpect((MockMvcResultMatchers.model()).attribute(“categories”,所有类别));
.andExpect(MockMvcResultMatchers.view().name(“类别”);
}
}
在测试方法
之前,请查看。我正在我创建的控制器的新实例上设置模拟DAO
,然后我正在使用控制器的同一实例创建模拟MVC
。我对提供的解决方案有一些问题,所以我想分享一下我是如何解决的信息技术我的问题是,当控制器在DAO上调用一个方法时,它抛出了NullPointerException,因为我不想使用setter注入向控制器提供模拟DAO(我拒绝在DAO中创建setter方法,只是为了能够测试一切)
基本上,OP需要:
未在setup()方法中实例化控制器(如Aman指出的)
在控制器声明之前使用@Mock注释声明DAO
像这样:
@RunWith(MockitoJUnitRunner.class)
public class CategoryControllerTest {
private MockMvc mockMvc;
@Mock
private SimpleCategoryDAO simpleCategoryDAO;
@InjectMocks
private CategoryController categoryController;
@Before
public void setup() {
mockMvc = MockMvcBuilders.standaloneSetup(categoryController).build();
}
@Test
public void categories_ShouldRenderCategoriesView() throws Exception {
List<Category> ALL_CATEGORIES = Arrays.asList(
new Category(1,"Funny"),
new Category(2,"JoyFul")
);
Mockito.when(simpleCategoryDAO.getAllCategories()).thenReturn(ALL_CATEGORIES);
mockMvc.perform(get("/categories"))
//.andExpect((MockMvcResultMatchers.model()).attribute("categories",ALL_CATEGORIES));
.andExpect(MockMvcResultMatchers.view().name("categories"));
}
}
@RunWith(MockitoJUnitRunner.class)
公共类CategoryController测试{
私有MockMvc-MockMvc;
@嘲弄
私有SimpleCategoryDAO SimpleCategoryDAO;
@注射模拟
私有类别控制器类别控制器;
@以前
公共作废设置(){
mockMvc=MockMvcBuilders.standaloneSetup(categoryController.build();
}
@试验
public void categories_ShouldRenderCategoriesView()引发异常{
列出所有类别=数组.asList(
新类别(1,“搞笑”),
新类别(2,“快乐”)
);
Mockito.when(simpleCategoryDAO.getAllCategories())。然后返回(所有类别);
mockMvc.perform(get(“/categories”))
//.andExpect((MockMvcResultMatchers.model()).attribute(“categories”,所有类别));
.andExpect(MockMvcResultMatchers.view().name(“类别”);
}
}
如果直接调用CategoryController的方法而不使用mockMvc
,测试它是否会更简单?可以通过自定义断言方法验证注释(如@RequestMapping
)的存在。只是想知道…您可以在没有mockmvc的情况下对控制器进行简单的测试。该方法只将控制器方法作为普通组件而不是mockmvc进行测试。这里我们模拟的是对handlerYes的实际调用,但是“模拟对handler的实际调用”究竟给了我们什么好处?我们可以检查HttpStatus代码是否正确返回。我们可以检查指定为GET的方法是否可以通过POST访问,反之亦然。我们可以检查返回的内容类型。如果我们将返回的内容设置为JSON,我们可以在测试中检查JSON是否实际返回。同样,我们可以使用jsonPath库来检查json是否完全按照我们希望的方式创建。请参阅本文。