如何配置springfox使用Gson而不是Jackson

Question

我试图使用Gson发送JsonObjects作为响应。这些JsonObjects是手工构造的，而不是使用objectMapper或GSON。我排除了所有与杰克逊有关的依赖关系。它工作得很好很好。后来，我尝试使用SpringFox添加Swagger文档。现在它抛出以下异常：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'objectMapperConfigurer' defined in springfox.documentation.spring.web.SpringfoxWebMvcConfiguration: Post-processing of merged bean definition failed; nested exception is java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/ObjectMapper
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:526) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:235) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:703) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:528) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
    at com.honeywell.ldi.LdiDetailerApplication.main(LdiDetailerApplication.java:44) ~[classes/:na]
Caused by: java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/ObjectMapper
    at java.lang.Class.getDeclaredMethods0(Native Method) ~[na:1.8.0_151]
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) ~[na:1.8.0_151]
    at java.lang.Class.getDeclaredMethods(Class.java:1975) ~[na:1.8.0_151]
    at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:613) ~[spring-core-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.util.ReflectionUtils.doWithLocalMethods(ReflectionUtils.java:489) ~[spring-core-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.buildLifecycleMetadata(InitDestroyAnnotationBeanPostProcessor.java:206) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.findLifecycleMetadata(InitDestroyAnnotationBeanPostProcessor.java:187) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(InitDestroyAnnotationBeanPostProcessor.java:125) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(CommonAnnotationBeanPostProcessor.java:295) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyMergedBeanDefinitionPostProcessors(AbstractAutowireCapableBeanFactory.java:992) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:523) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
    ... 15 common frames omitted
Caused by: java.lang.ClassNotFoundException: com.fasterxml.jackson.databind.ObjectMapper
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_151]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_151]
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335) ~[na:1.8.0_151]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_151]
    ... 26 common frames omitted

Answer 1

出现异常是由于springfox.documentation.spring.web.objectMapperConfigurer抱怨缺少com.fasterxml.jackson.databind.objectMapper。

ObjectMapper存在于com.fasterxml.jackson.core:jackson-databind:jar中。您仍然需要jackson-databindJAR来使您的应用程序与SpringFox一起工作。

至于SpringFox，它不适合Gson开箱即用。您需要使用GSON对象为不同的Springfox工件注册自定义序列化器。

Gson gson = GsonBuilder()
    // needed for making calls to /v2/api-docs
    .registerTypeAdapter(Json.class, 
        new SpringfoxJsonSerializer())
    // rest are needed for making calls to /swagger-ui.html
    .registerTypeAdapter(ApiListing.class, 
        new SpringfoxApiListingJsonSerializer())
    .registerTypeAdapter(SwaggerResource.class, 
        new SpringfoxResourceJsonSerializer())
    .registerTypeAdapter(ResourceListing.class, 
        new SpringfoxResourceListingJsonSerializer())
    .registerTypeAdapter(UiConfiguration.class, 
        new SpringfoxUiConfigurationJsonSerializer())
    // needed if you have security
    .registerTypeAdapter(SecurityConfiguration.class, 
        new SpringfoxSecurityConfigurationJsonSerializer())
    ...
    .create();