自定义的 ObjectMapper 未在测试中使用

Question

我正在使用 Spring 框架，版本 4.1.6，带有 Spring 网络服务，没有 Spring 启动。为了学习该框架，我正在编写一个 REST API 并进行测试以确保从命中端点接收到的 JSON 响应是正确的。具体来说，我正在尝试调整 ObjectMapper 的 PropertyNamingStrategy 以使用 "lower case with underscores" 命名策略。

我正在使用 the method detailed on Spring's blog 创建一个新的 ObjectMapper 并将其添加到转换器列表中。如下：

package com.myproject.config;

import com.fasterxml.jackson.databind.PropertyNamingStrategy;
import org.springframework.context.annotation.*;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import java.util.List;

@Configuration
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        Jackson2ObjectMapperBuilder builder = jacksonBuilder();
        converters.add(new MappingJackson2HttpMessageConverter(builder.build()));
    }

    public Jackson2ObjectMapperBuilder jacksonBuilder() {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
        builder.propertyNamingStrategy(PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);

        return builder;
    }
}

然后我运行进行以下测试（使用JUnit、MockMvc和Mockito）来验证我的更改：

package com.myproject.controller;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.springframework.http.MediaType;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.AnnotationConfigWebContextLoader;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.MvcResult;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;

import static org.mockito.Mockito.when;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

// Along with other application imports...

@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration(classes = {WebConfig.class}, loader = AnnotationConfigWebContextLoader.class)
public class MyControllerTest {

    @Mock
    private MyManager myManager;

    @InjectMocks
    private MyController myController;

    private MockMvc mockMvc;

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


    @Test
    public void testMyControllerWithNameParam() throws Exception {
        MyEntity expected = new MyEntity();
        String name = "expected";
        String title = "expected title";

        // Set up MyEntity with data.
        expected.setId(1); // Random ID.
        expected.setEntityName(name);
        expected.setEntityTitle(title)

        // When the MyManager instance is asked for the MyEntity with name parameter,
        // return expected.
        when(this.myManager.read(name)).thenReturn(expected);

        // Assert the proper results.
        MvcResult result = mockMvc.perform(
                get("/v1/endpoint")
                    .param("name", name))
                .andExpect(status().isOk())
                .andExpect((content().contentType("application/json;charset=UTF-8")))
                .andExpect(jsonPath("$.entity_name", is(name))))
                .andExpect(jsonPath("$.entity_title", is(title)))
                .andReturn();

        System.out.println(result.getResponse().getContentAsString());
    }
}

但是，这个 returns 的响应是：

{"id": 1, "entityName": "expected", "entityTitle": "expected title"}

我什么时候应该得到：

{"id": 1, "entity_name": "expected", "entity_title": "expected title"}

我有一个扫描包的已实现的 WebApplicationInitializer：

package com.myproject.config;

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

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

public class WebAppInitializer implements WebApplicationInitializer {

    public void onStartup(ServletContext servletContext) throws ServletException {
        AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
        ctx.scan("com.myproject.config");
        ctx.setServletContext(servletContext);

        ServletRegistration.Dynamic servlet = servletContext.addServlet("dispatcher", new DispatcherServlet(ctx));
        servlet.setLoadOnStartup(1);
        servlet.addMapping("/");

        servletContext.addListener(new ContextLoaderListener(ctx));
    }
}

在 IntelliJ 中使用我的调试器，我可以看到生成器已创建并添加，但在某处生成的 ObjectMapper 并未实际使用。我一定是遗漏了什么，但我设法找到的所有例子似乎都没有提到那是什么！我已经尝试消除 @EnableWebMvc 并实现 WebMvcConfigurationSupport，使用 MappingJackson2HttpMessageConverter 作为 Bean，并将 ObjectMapper 设置为 Bean 无济于事。

如有任何帮助，我们将不胜感激！如果需要任何其他文件，请告诉我。

谢谢！

编辑： 进行了更多挖掘，发现 this。在 link 中，作者在 he/she 构建 MockMvc 之前附加了 setMessageConverters() 并且它适用于作者。做同样的事情对我也有用；但是，我不确定是否所有内容都可以在生产中使用，因为存储库尚未清除。当我发现我会提交一个答案。

编辑 2： 查看答案。

Answer 1

我了解了为什么会这样工作。重申一下，让我的自定义 ObjectMapper 在我的测试中工作的过程（假设 MockMvc 被创建为独立的）如下：

创建一个扩展 WebMvcConfigurerAdapter.

WebConfig

在WebConfigclass中新建一个@Bean，即returns一个MappingJackson2HttpMessageConverter。这个 MappingJackson2HttpMessageConverter 应用了所需的更改（在我的例子中，它传递给它一个 Jackson2ObjectMapperBuilder，PropertyNamingStrategy 设置为 CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES。）
同样在 WebConfig class、@Override configureMessageConverters() 中并将 (2) 中的 MappingJackson2HttpMessageConverter 添加到消息转换器列表中。
在测试文件中，添加一个@ContextConfiguration(classes = { WebConfig.class })注解来告知测试你的@Bean。
使用@Autowired注入并访问(2)中定义的@Bean。
在 MockMvc 的设置中，使用 .setMessageConverters() 方法并将其传递给注入的 MappingJackson2HttpMessageConverter。测试现在将使用 (2) 中设置的配置。

测试文件：

package com.myproject.controller;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.springframework.http.MediaType;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.AnnotationConfigWebContextLoader;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.MvcResult;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;

import static org.mockito.Mockito.when;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

// Along with other application imports...

@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration(classes = {WebConfig.class})
public class MyControllerTest {

    /**
     * Note that the converter needs to be autowired into the test in order for
     * MockMvc to recognize it in the setup() method.
     */
    @Autowired
    private MappingJackson2HttpMessageConverter jackson2HttpMessageConverter;

    @Mock
    private MyManager myManager;

    @InjectMocks
    private MyController myController;

    private MockMvc mockMvc;

    @Before
    public void setup() {
        MockitoAnnotations.initMocks(this);
        this.mockMvc = MockMvcBuilders
            .standaloneSetup(this.myController)
            .setMessageConverters(this.jackson2HttpMessageConverter) // Important!
            .build();
    }


    @Test
    public void testMyControllerWithNameParam() throws Exception {
        MyEntity expected = new MyEntity();
        String name = "expected";
        String title = "expected title";

        // Set up MyEntity with data.
        expected.setId(1); // Random ID.
        expected.setEntityName(name);
        expected.setEntityTitle(title)

        // When the MyManager instance is asked for the MyEntity with name parameter,
        // return expected.
        when(this.myManager.read(name)).thenReturn(expected);

        // Assert the proper results.
        MvcResult result = mockMvc.perform(
                get("/v1/endpoint")
                    .param("name", name))
                .andExpect(status().isOk())
                .andExpect((content().contentType("application/json;charset=UTF-8")))
                .andExpect(jsonPath("$.entity_name", is(name))))
                .andExpect(jsonPath("$.entity_title", is(title)))
                .andReturn();

        System.out.println(result.getResponse().getContentAsString());
    }
}

和配置文件：

package com.myproject.config;
import com.fasterxml.jackson.databind.PropertyNamingStrategy;
import org.springframework.context.annotation.*;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import java.util.List;

@Configuration
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(jackson2HttpMessageConverter());
    }

    @Bean
    public MappingJackson2HttpMessageConverter jackson2HttpMessageConverter() {
        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
        Jackson2ObjectMapperBuilder builder = this.jacksonBuilder();
        converter.setObjectMapper(builder.build());

        return converter;
    }

    public Jackson2ObjectMapperBuilder jacksonBuilder() {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder(); 
        builder.propertyNamingStrategy(PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);

        return builder;
    }
}

将我生成的 WAR 文件部署到 Tomcat 7 in XAMPP 表明命名策略使用正确。我相信它之所以如此工作，是因为在独立设置中，除非另有说明，否则始终使用一组默认的消息转换器。这可以在 StandAloneMockMvcBuilder.java（版本 4.1.6，\org\springframework\test\web\servlet\setup\StandaloneMockMvcBuilder.java）中的 setMessageConverters() 函数的注释中看到：

   /**
     * Set the message converters to use in argument resolvers and in return value
     * handlers, which support reading and/or writing to the body of the request
     * and response. If no message converters are added to the list, a default
     * list of converters is added instead.
     */
    public StandaloneMockMvcBuilder setMessageConverters(HttpMessageConverter<?>...messageConverters) {
        this.messageConverters = Arrays.asList(messageConverters);
        return this;
    }

因此，如果 MockMvc 在构建 MockMvc 期间未明确告知对消息转换器的更改，它将不会使用这些更改。

Answer 2

或者你可以

MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter = new
            MappingJackson2HttpMessageConverter();
    mappingJackson2HttpMessageConverter.setObjectMapper( new ObjectMapper().setPropertyNamingStrategy(
            PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES) );
    mockMvc = MockMvcBuilders.standaloneSetup(attributionController).setMessageConverters(
            mappingJackson2HttpMessageConverter ).build();

Answer 3

使用 Spring Boot 1.5.1 我可以做到：

@RunWith(SpringRunner.class)
@AutoConfigureJsonTesters
@JsonTest
public class JsonTest {

    @Autowired
    ObjectMapper objectMapper;
}

以与运行时相同的方式访问配置的 ObjectMapper。

我的runtime jackson是这样配置的：

@Configuration
public class JacksonConfiguration {

    @Autowired
    Environment environment;

    @Bean
    public Jackson2ObjectMapperBuilderCustomizer jacksonCustomizer() {
        return builder -> {
            builder.locale(new Locale("sv", "SE"));

            if (JacksonConfiguration.this.environment == null
                    || !JacksonConfiguration.this.environment.acceptsProfiles("docker")) {
                builder.indentOutput(true);
            }

            final Jdk8Module jdk8Module = new Jdk8Module();

            final ProblemModule problemModule = new ProblemModule();

            final JavaTimeModule javaTimeModule = new JavaTimeModule();

            final Module[] modules = new Module[] { jdk8Module, problemModule,
                javaTimeModule };
            builder.modulesToInstall(modules);
        };
    }
}

Answer 4

在 Spring 引导中，当对控制器层 (@WebMvcTest) 进行单元测试时，您可以访问对象映射器，因此您可以在测试用例之前对其进行修改：

@Autowired
private ObjectMapper objectMapper;

@Before
public void init(){
    objectMapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);
}

自定义的 ObjectMapper 未在测试中使用

Customized ObjectMapper not used in test

spring

spring-mvc

jackson