Question

我的JUnit测试用例失败了。第

行发生错误

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

失败追踪

java.lang.NullPointerException at com.sample.controller.BlogEntryControllerTest.getExistingBlogEntry（BlogEntryControllerTest.java:72） at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method）at sun.reflect.NativeMethodAccessorImpl.invoke（未知来源）at sun.reflect.DelegatingMethodAccessorImpl.invoke（未知来源）at java.lang.reflect.Method.invoke（未知来源）at 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）at at org.junit.runners.ParentRunner $ 1.schedule（ParentRunner.java:71）at at org.junit.runners.ParentRunner.runChildren（ParentRunner.java:288）at at org.junit.runners.ParentRunner.access $ 000（ParentRunner.java:58）at at org.junit.runners.ParentRunner $ 2.evaluate（ParentRunner.java:268）at at 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）at 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为null

我的代码是

    /**
 * TODO - Describe purpose and operation of class.
 * 
 * <table border="1" cellpadding="0" cellspacing="0" width="100%">
 * <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" width="100%">
 * <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" width="100%">
 * <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));

    }
}

Answer 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());
}

Answer 2

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

blogEntryService = new BlogEntryService();

Answer 3

Rohit的上述答案帮助并解决了原始的嘲弄问题，以下是我尝试过的替代方案，但它只是替代方案而不是解决方案。

我评论了以下一行

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

来自BlogEntryControllerTest.java的

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();

}

而不是webAppContextSetup，它将更改为StandaloneSetup 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

public BlogEntryController（BlogEntryService blogEntryService）{
    this.blogEntryService = blogEntryService;
}

现在，当我执行测试模拟时，blogEntryService正在正确注入。

当我使用webAppContextSetup时，我必须保留默认构造函数 BlogEntryController。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执行并且blogEntryService保持为null并且测试失败。

即使我能够使这个工作，这不是解决方案，它只是一个替代方案。

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

Spring MVC应用程序Junit测试用例失败

3 个答案: