MessageBodyProviderNotFoundException,ModelValidationException

在使用dropwizard开发文件上传服务的时候，需要使用Jersy的扩展包：

    <dependency>        <groupId>org.glassfish.jersey.media</groupId>        <artifactId>jersey-media-multipart</artifactId>        <version>${multipart.version}</version>    </dependency>

在Resource中使用@FormDataParam

  @Consumes(MediaType.MULTIPART_FORM_DATA)    @POST    public Response upload(            @FormDataParam("name") String name,            @FormDataParam("file") InputStream inputStream    )

在Application中注册Multipart的Provider：

@Override    public void run(final FileConfiguration configuration,                    final Environment environment) {        environment.jersey().register(MultiPartFeature.class);        environment.jersey().register(new MyResource());    }

否则会报异常：

org.glassfish.jersey.server.model.ModelValidationException: Validation of the application resource model has failed during application initialization.[[FATAL] No injection source found for a parameter of type public javax.ws.rs.core.Response me.ligen.file.resources.FileResource.upload(java.lang.String,java.io.InputStream) throws java.lang.Exception at index 0.; source='ResourceMethod{httpMethod=POST, consumedTypes=[multipart/form-data], producedTypes=[], suspended=false, suspendTimeout=0, suspendTimeoutUnit=MILLISECONDS, 

接下来要说的是重点，有单元测试习惯的同学，一定会使用Dropwizard提供的ResourceTestRule，那么极有会碰到这个异常：

org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyWriter not found for media type=multipart/form-data, type=class org.glassfish.jersey.media.multipart.FormDataMultiPart, genericType=class org.glassfish.jersey.media.multipart.FormDataMultiPart

原因是客户端也需要注册MultiPartFeature，否则无法找到对应的Provider。解决办法如下：

@ClassRule    public static final ResourceTestRule RESOURCE_TEST_RULE = ResourceTestRule.builder()            .setClientConfigurator(clientConfig -> clientConfig.register(MultiPartFeature.class))            .addProvider(MultiPartFeature.class)            .addResource(new MyResource())            .build();

这样就能美美得UT了。