使用Spring MVC和Mockito进行MockMvc测试时没有JSON内容（为空

Question

有一个使用SpringMVC4.0.3.Release的代码库，用于Restful Web服务。

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>4.0.3.RELEASE</version>
</dependency>

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>4.0.3.RELEASE</version>
</dependency>

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>4.0.3.RELEASE</version>
    <scope>test</scope>
</dependency>

<!-- A bunch of other Spring libs omitted from this post -->

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>3.1.0</version>
    <scope>provided</scope>
</dependency>

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
    <exclusions>
        <exclusion>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-core</artifactId>
        </exclusion>
    </exclusions>
</dependency>

<dependency>
    <groupId>org.hamcrest</groupId>
    <artifactId>hamcrest-all</artifactId>
    <version>1.3</version>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-core</artifactId>
    <version>1.10.19</version>
    <exclusions>
        <exclusion>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-core</artifactId>
        </exclusion>
    </exclusions>
    <scope>test</scope>
</dependency>

<dependency>
    <groupId>com.jayway.jsonpath</groupId>
    <artifactId>json-path-assert</artifactId>
    <version>0.9.1</version>
    <scope>test</scope>
</dependency>

package com.myapp.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@EnableWebMvc
@Configuration
@ComponentScan("com.myapp.rest")
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
        configurer.defaultContentType(MediaType.APPLICATION_JSON);
    }
}

ServletInitializer：

package com.myapp.config;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

import com.myapp.config.WebConfig;

public class ServletInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

    protected Class<?>[] getServletConfigClasses() {
        return new Class[] { WebConfig.class };
    }

    @Override
    protected String[] getServletMappings() {
        return new String[] { "/" };
    }

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return null;
    }
}

用户控制器：

@RestController
@RequestMapping("/v2")
public class UserController {

    private final UserDAO dao;

    private HttpHeaders headers = null;

    @Autowired 
    public UserController(UserDAO dao) {
        this.dao = dao;
        headers = new HttpHeaders();
        headers.add("Content-Type", "application/json");
    }

    @RequestMapping(value = "users/{appId}", method = RequestMethod.GET, produces="application/json")
    @ResponseBody 
    public ResponseEntity<Object> getUserDetails(@PathVariable String appId) {
        Object jsonPayload = dao.getUser(appId);
        return new ResponseEntity<Object>(jsonPayload, headers, HttpStatus.OK);
    }
}

用户道：

@Repository
public class UserDAO {

    private JdbcTemplate jdbcTemplate;

    @Autowired
    public UserDAO(@Qualifier("dataSourceDB") DataSource dataSource) {
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }

    // Finders methods (such as the getUser(appId)) which use Spring JDBC
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4"
    xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

    <display-name>MyApp</display-name>

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

    <servlet>
        <servlet-name>mvc-dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>mvc-dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value>
    </context-param>
</web-app>

<beans xmlns="http://www.springframework.org/schema/beans">

    <import resource="classpath:database.xml" />
    <context:component-scan base-package="com.myapp.rest" />
    <mvc:annotation-driven />

    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix">
            <value>/WEB-INF/pages/</value>
        </property>
        <property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>
</beans>

<beans xmlns="http://www.springframework.org/schema/beans">
    <bean id="dataSourceDB" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName"><value>${jdbc.driver}</value></property>
        <property name="url"><value>${db.url}</value></property>
        <property name="username"><value>${db.username}</value></property>
        <property name="password"><value>${db.password}</value></property>
    </bean>
</beans>

RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:**/mvc-dispatcher-servlet.xml")
@WebAppConfiguration
public class UserControllerTest {

    private MockMvc mockMvc;

    @Mock
    private UserDAO dao;

    @InjectMocks
    private UserController controller;

    @Before
    public void setUp() {
        MockitoAnnotations.initMocks(this);
        mockMvc = MockMvcBuilders.standaloneSetup(controller).build();
    }

    @Test
    public void getUserDetails() throws Exception {
        String appId = "23bdr4560l";
        mockMvc.perform(get("/v2/users/{appId}",appId)
               .accept(MediaType.APPLICATION_JSON))
               .andExpect(content().contentType(MediaType.APPLICATION_JSON))
               .andExpect(status().isOk())
               .andDo(print());
    }
}

当我在本地调用构建时：

mvn clean install

生成到stdout的输出：

正在运行com.myapp.rest.controllers.UserControllerTest

MockHttpServletRequest:
         HTTP Method = GET
         Request URI = /v2/users/23bdr4560l
          Parameters = {}
             Headers = {Accept=[application/json]}

             Handler:
                Type = com.myapp.rest.controllers.UserController
              Method = public org.springframework.http.ResponseEntity<java.lang.Object> com.myapp.rest.controllers.UserController.getUserDetails(java.lang.String)

               Async:
   Was async started = false
        Async result = null

  Resolved Exception:
                Type = null

        ModelAndView:
           View name = null
                View = null
               Model = null

            FlashMap:

MockHttpServletResponse:
              Status = 200
       Error message = null
             Headers = {Content-Type=[application/json]}
        Content type = application/json
                Body = 
       Forwarded URL = null
      Redirected URL = null
             Cookies = []
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.728 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

Body = 

@Test
public void getUserDetails() throws Exception {
    String appId = "23bdr4560l";
    mockMvc.perform(get("/v2/users/{appId}",appId)
           .accept(MediaType.APPLICATION_JSON))
           .andExpect(content().contentType(MediaType.APPLICATION_JSON))
           .andExpect(status().isOk())
           .andExpect(jsonPath("$", hasSize(2)))
           .andDo(print());
}

Results :

Tests in error: 
  getUserDetails(com.myapp.rest.controllers.UserControllerTest): json can not be null or empty

Tests run: 1, Failures: 0, Errors: 1, Skipped: 0

我到底做错了什么？

显然，我需要模拟出响应，但我在谷歌上搜索了这个结果，其他使用MockMvc的人能够获得一个JSON他们的测试。

这是一个配置问题吗（我需要为我的单元测试放置某种类型的注释吗）？

我非常感谢任何帮助...

Answer 1

当您试图像这样模拟bean时，它会尝试使用默认构造函数创建模拟。

@Mock
private UserDAO dao

它适用于实际的rest调用，因为您在运行时提供了依赖的datasource。为UserDAO类提供有效的从属模拟是可行的。