Spring MVC 应用程序 Junit 测试用例失败

Posted 2023-02-27

【中文标题】Spring MVC 应用程序 Junit 测试用例失败

【英文标题】：Spring MVC application Junit test case failing

【发布时间】：2016-04-30 21:45:08

【问题描述】：

我的 JUnit 测试用例失败了。行发生错误

Mockito.when(blogEntryService.find(1L)).thenReturn(entry);

故障跟踪是

java.lang.NullPointerException 在 com.sample.controller.BlogEntryControllerTest.getExistingBlogEntry(BlogEntryControllerTest.java:72) 在 sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 在 sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke（未知来源）在 java.lang.reflect.Method.invoke（未知来源）在 org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) 在 org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) 在 org.junit.runners.model.FrameworkMethod.invokeExplosively（FrameworkMethod.java:47） 在 org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) 在 org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) 在 org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74) 在 org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83) 在 org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) 在 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233) 在 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87) 在 org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) 在 org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) 在 org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) 在 org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) 在 org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) 在 org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) 在 org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) 在 org.junit.runners.ParentRunner.run(ParentRunner.java:363) 在 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176) 在 org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) 在 org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) 在 org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) 在 org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) 在 org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) 在 org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

在我看来 blogEntryService 是空的

我的代码是

    /**
 * TODO - Describe purpose and operation of class.
 * 
 * <table border="1" cellpadding="0" cellspacing="0" >
 * <caption align="center">Edit and Version History</caption>
 * <tr><th>Version</th><th>Date</th><th>Author</th><th>Description</th></tr>
 * <tr><td>1.0</td><td>Jan 17, 2016</td><td>EOV537</td><td>Initial creation.</td></tr>
 * </table>
 */
package com.sample.controller;

import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.forwardedUrl;

import org.hamcrest.Matchers;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.MockitoAnnotations;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

import com.sample.config.ApplicationConfig;
import com.sample.model.BlogEntry;
import com.sample.service.BlogEntryService;

/**
 * @author EOV537 -
 * @since 1.0
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = ApplicationConfig.class)
@WebAppConfiguration
public class BlogEntryControllerTest 

    private MockMvc mockMvc;

    @InjectMocks
    private BlogEntryController blogentryconttroller;

    @Mock
    private BlogEntryService blogEntryService;

    @Autowired
    private WebApplicationContext appCtx;

    @Before
    public void setup() 

        MockitoAnnotations.initMocks(BlogEntryControllerTest.class);
        mockMvc = MockMvcBuilders.webAppContextSetup(appCtx).build();
    

    @Test
    public void getExistingBlogEntry() throws Exception 

        BlogEntry entry = new BlogEntry();
        entry.setId(1L);
        entry.setTitle("Test Title");

        Mockito.when(blogEntryService.find(1L)).thenReturn(entry);

        mockMvc.perform(MockMvcRequestBuilders.get("/rest/blog-entries/1"))
                .andExpect(MockMvcResultMatchers.jsonPath("$.title", Matchers.is("Test Title")))
                .andExpect(
                        MockMvcResultMatchers.jsonPath("$.links[*].href",
                                Matchers.hasItem(Matchers.endsWith("/blog-entries/1"))))
                .andExpect(MockMvcResultMatchers.status().isOk());
    

    public void getNonExistingBlogEntry() throws Exception 

        Mockito.when(blogEntryService.find(1L)).thenReturn(null);
        mockMvc.perform(MockMvcRequestBuilders.get("/rest/blog-entries/1")).andExpect(
                MockMvcResultMatchers.status().isNotFound());
    

BlogEntryController.Java

package com.sample.controller;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import com.sample.assembler.BlogEntryResourceAsm;
import com.sample.model.BlogEntry;
import com.sample.resource.BlogEntryResource;
import com.sample.service.BlogEntryService;

/**
 * @author EOV537 -
 * @since 1.0
 */
@Controller
@RequestMapping(value = "/rest/blog-enteries")
public class BlogEntryController 

    public BlogEntryController() 

    

    public BlogEntryController(BlogEntryService blogEntryService) 

        this.blogEntryService = blogEntryService;
    

    private BlogEntryService blogEntryService;

    @RequestMapping(value = "/blogEntryId", method = RequestMethod.GET)
    public ResponseEntity<BlogEntryResource> getExsitingBlogEntry(@PathVariable Long blogEntryId) 

        BlogEntry entry = blogEntryService.find(blogEntryId);

        if (entry != null) 
            BlogEntryResource res = new BlogEntryResourceAsm().toResource(entry);
            return new ResponseEntity<BlogEntryResource>(res, HttpStatus.OK);
         else 
            return new ResponseEntity<BlogEntryResource>(HttpStatus.NOT_FOUND);
        
    

BlogEntryService.Java

package com.sample.service;

import org.springframework.stereotype.Component;

import com.sample.model.BlogEntry;

/**
 * @author EOv537 -
 * 
 * @since 1.0
 */

public interface BlogEntryService 
    public BlogEntry find(Long id);

BlogEntryResource.java

package com.sample.resource;

import org.springframework.hateoas.ResourceSupport;

/**
 * @author EOv537 -
 * @since 1.0
 */
public class BlogEntryResource extends ResourceSupport 

    private String title;

    public String getTitle() 
        return title;
    

    public void setTitle(String title) 
        this.title = title;
    

BlogEntryResourceAsm.java

public class BlogEntryResourceAsm extends ResourceAssemblerSupport<BlogEntry, BlogEntryResource> 

    /**
     * @param controllerClass
     * @param resourceType
     */
    public BlogEntryResourceAsm() 
        super(BlogEntryController.class, BlogEntryResource.class);
        // TODO Auto-generated constructor stub
    

    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.hateoas.ResourceAssembler#toResource(java.lang.Object)
     */
    @Override
    public BlogEntryResource toResource(BlogEntry blogEntry) 

        BlogEntryResource res = new BlogEntryResource();
        res.setTitle(blogEntry.getTitle());
        Link link = ControllerLinkBuilder.linkTo(BlogEntryController.class).slash(blogEntry.getId()).withSelfRel();
        return res;

    

ApplicationConfig.java

/**
 * TODO - Describe purpose and operation of class.
 * 
 * <table border="1" cellpadding="0" cellspacing="0" >
 * <caption align="center">Edit and Version History</caption>
 * <tr><th>Version</th><th>Date</th><th>Author</th><th>Description</th></tr>
 * <tr><td>1.0</td><td>Jan 17, 2016</td><td>EOV537</td><td>Initial creation.</td></tr>
 * </table>
 */
package com.sample.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

/**
 * @author EOV537 -
 * @since 1.0
 */
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.sample")
public class ApplicationConfig extends WebMvcConfigurerAdapter 

    private static final String VIEW_RESOLVER_PREFIX = "/WEB-INF/jsp/";

    private static final String VIEW_RESOLVER_SUFFIX = ".jsp";

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) 
        registry.addResourceHandler("/static/**").addResourceLocations("/static/");
    

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) 
        configurer.enable();
    

    @Bean
    public ViewResolver viewResolver() 
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();

        // viewResolver.setViewClass(InternalResourceViewResolver.class); // NOSONAR
        viewResolver.setPrefix(VIEW_RESOLVER_PREFIX);
        viewResolver.setSuffix(VIEW_RESOLVER_SUFFIX);

        return viewResolver;
    

WebApplint.java

/**
 * TODO - Describe purpose and operation of class.
 * 
 * <table border="1" cellpadding="0" cellspacing="0" >
 * <caption align="center">Edit and Version History</caption>
 * <tr><th>Version</th><th>Date</th><th>Author</th><th>Description</th></tr>
 * <tr><td>1.0</td><td>Jan 17, 2016</td><td>EOV537</td><td>Initial creation.</td></tr>
 * </table>
 */
package com.sample.config;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

/**
 * @author EOV537 -
 * @since 1.0
 */
public class WebApplint implements WebApplicationInitializer 
    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.web.WebApplicationInitializer#onStartup(javax.servlet.ServletContext)
     */
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException 

        AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
        rootContext.register(ApplicationConfig.class);

        ServletRegistration.Dynamic registration = servletContext.addServlet("DispatcherServlet",
                new DispatcherServlet(rootContext));

        registration.addMapping("/");

        registration.setLoadOnStartup(1);
        servletContext.addListener(new ContextLoaderListener(rootContext));

    

【参考方案1】：

private MockMvc mockMvc;

@Autowired
@InjectMocks
private BlogEntryController blogentryconttroller;

@Autowired
private WebApplicationContext appCtx;

@Mock
BlogEntryService blogEntryService;

@Before
public void setup() 
    MockitoAnnotations.initMocks(BlogEntryControllerTest.this);
    mockMvc = MockMvcBuilders.webAppContextSetup(appCtx).build();


@Test
public void getExistingBlogEntry() throws Exception 
    BlogEntry entry = new BlogEntry();
    entry.setId(1L);
    entry.setTitle("Test Title");
    Mockito.when(blogEntryService.find(1L)).thenReturn(entry);
    mockMvc.perform(MockMvcRequestBuilders.get("/rest/blog-enteries/1"))
            .andExpect(MockMvcResultMatchers.status().isOk());

【讨论】：

我要使用注解@Mock private BlogEntryService blogEntryService;如果您看到我已经上过的课程，那是不是这种方法不正确？

使用您的解决方案 BlogEntryService blogEntryService = Mockito.mock(BlogEntryService.class); Mockito 给了我代理实现，我不需要添加实现和初始化，但我不明白为什么@mock 不起作用。

我确实初始化了，看看我的代码 MockitoAnnotations.initMocks(BlogEntryControllerTest.class);

使用您的解决方案，我可以前进 1 步，但在测试执行后仍然失败 2016-01-24 11:21:21 DEBUG TestDispatcherServlet:984 - 无法完成请求 java.lang。 com.sample.controller.BlogEntryController.getExsitingBlogEntry(BlogEntryController.java:49) 处的 NullPointerException

我没有服务实现，这就是我使用模拟的原因。这是我的存储库的链接github.com/satyajitn/rest-service 我正在做测试驱动开发，所以在服务实现之前编写测试用例

【参考方案2】：

在 BlogEntryController() 中，blogEntryService 永远不会用值初始化。在您的 @Before (setup()) 方法中，初始化 blogEntryService：

blogEntryService = new BlogEntryService();

【讨论】：

blogEntryService 是接口，无法解析为变量。请看代码

【参考方案3】：

Rohit 的上述回答帮助并解决了最初的模拟问题，这是我尝试过的替代方案并且它有效，但它只是替代方案而不是解决方案。

我评论了下面一行

//@RunWith(SpringJUnit4ClassRunner.class)
//@ContextConfiguration(classes = ApplicationConfig.class)

来自 BlogEntryControllerTest.java

我将 setup() 方法从 BlogEntryControllerTest 更改为

@Before
public void setup() 

    // blogEntryService = Mockito.mock(BlogEntryService.class);
    MockitoAnnotations.initMocks(this);
    mockMvc = MockMvcBuilders.standaloneSetup(blogentryconttroller).build();
    //mockMvc = MockMvcBuilders.webAppContextSetup(appCtx).build();

改为 StandaloneSetup 而不是 webAppContextSetup 然后

更新了 BlogEntryController 并删除了默认构造函数

// public BlogEntryController()

//

现在只有 1 个构造函数

公共 BlogEntryController(BlogEntryService blogEntryService)

    this.blogEntryService = blogEntryService;

现在，当我执行测试时，模拟的 blogEntryService 正在正确注入。

当我使用 webAppContextSetup 时，我必须保留默认构造函数 博客条目控制器。因为它有默认构造函数，所以当我运行测试时 默认构造函数被执行并且 blogEntryService 保持为空并且测试失败。

即使我能够做到这一点，这也不是解决方案，它只是一种替代方案。

如果有人知道如何通过 webAppContextSetup 解决此问题，请发布解决方案。