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提问者：小点点

使用泽西2.2和杰克逊2.1的自定义对象映射器


我正在努力使用Grizzly、泽西和Jackson的REST应用程序，因为泽西忽略了我的自定义ObjectMapper。

聚甲醛依赖关系：

<dependencies>
    <dependency>
        <groupId>org.glassfish.jersey.containers</groupId>
        <artifactId>jersey-container-grizzly2-servlet</artifactId>
        <version>2.2</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.jaxrs</groupId>
        <artifactId>jackson-jaxrs-json-provider</artifactId>
        <version>2.1.4</version>
    </dependency>
</dependencies>

生成的版本是：Grizzly 2.3.3、Jackson 2.1.4和泽西2.2。

主类（我想要Jersey组件的显式注册）：

public class Main {
    public static void main(String[] args) {
        try {
            ResourceConfig rc = new ResourceConfig();
            rc.register(ExampleResource.class);
            rc.register(ObjectMapperResolver.class);

            HttpHandler handler = ContainerFactory.createContainer(
                    GrizzlyHttpContainer.class, rc);

            URI uri = new URI("http://0.0.0.0:8080/");

            HttpServer server = GrizzlyHttpServerFactory.createHttpServer(uri);

            ServerConfiguration config = server.getServerConfiguration();
            config.addHttpHandler(handler, "/");

            server.start();
            System.in.read();

        } catch (ProcessingException | URISyntaxException | IOException e) {
            throw new Error("Unable to create HTTP server.", e);
        }
    }
}

对象映射器的ContextResolver:

@Provider
@Produces(MediaType.APPLICATION_JSON)
public class ObjectMapperResolver implements ContextResolver<ObjectMapper> {

    private final ObjectMapper mapper;

    public ObjectMapperResolver() {
        System.out.println("new ObjectMapperResolver()");
        mapper = new ObjectMapper();
        mapper.enable(SerializationFeature.INDENT_OUTPUT);
    }

    @Override
    public ObjectMapper getContext(Class<?> type) {
        System.out.println("ObjectMapperResolver.getContext(...)");
        return mapper;
    }

}

无论是ObjectMapperResolver构造函数还是getContext都不会被调用。我错过了什么？我更喜欢使用Jersey 2.2和Jackson 2.1，因为它是另一个lib的依赖项。

可以在GitHub上找到一个完整的示例：https://github.com/svenwltr/example-grizzly-jersey-jackson/tree/stackoverflow


共3个答案

匿名用户

以下解决方案适用于以下堆栈(如...这是我用来测试它的设置)

我正在添加我的信息，其中包含我在这篇文章中提出的解决方案，因为它与我今天输入的许多 Google 搜索非常相关......这是一个繁琐的解决方案，我认为这是一个更加繁琐的问题。

<dependency>
    <groupId>com.fasterxml.jackson.jaxrs</groupId>
    <artifactId>jackson-jaxrs-json-provider</artifactId>
    <version>2.4.1</version>
</dependency>

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-json-jackson</artifactId>
</dependency>

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider;

import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.Provider;

@Provider
@Produces(MediaType.APPLICATION_JSON)
public class CustomJsonProvider extends JacksonJaxbJsonProvider {

    private static ObjectMapper mapper = new ObjectMapper();

    static {
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        mapper.setSerializationInclusion(JsonInclude.Include.ALWAYS);
        mapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        mapper.enable(SerializationFeature.INDENT_OUTPUT);
     }

    public CustomJsonProvider() {
        super();
        setMapper(mapper);
    }
}

如您所见，这也是我们定义com. firerxml.jackson.data.ObjectMapper的自定义实例的地方

import javax.ws.rs.core.Feature;
import javax.ws.rs.core.FeatureContext;
import javax.ws.rs.ext.MessageBodyReader;
import javax.ws.rs.ext.MessageBodyWriter;

public class MarshallingFeature implements Feature {

    @Override
    public boolean configure(FeatureContext context) {
        context.register(CustomJsonProvider.class, MessageBodyReader.class, MessageBodyWriter.class);
        return true;
    }
}

import org.glassfish.jersey.server.ResourceConfig;
...

public class MyApplication extends ResourceConfig {

    public MyApplication() {

        ...
        register(MarshallingFeature.class);
        ...
     }
 }

其他说明和意见：

  1. 无论您是否使用javax.ws.rs.core.Respons来包装控制器的响应，此解决方案都适用
  2. 请确保仔细考虑（复制/粘贴）以下代码段，因为可以说，唯一的“非强制性”位是关于com.fasterxml.jackson.databind.ObjectMapper的自定义配置的位

很抱歉把球丢在了这个@jcreason上，我希望你仍然好奇。所以我检查了去年的代码，这就是我想出的，以提供一个自定义映射器。

问题是，在功能初始化过程中，任何自定义对象映射器都会被中的某些代码禁用

org.glassfish.jersey.jackson.JacksonFeature:77（jersey-media-json-jackson-2.12.jar）

// Disable other JSON providers.
context.property(PropertiesHelper.getPropertyNameForRuntime(InternalProperties.JSON_FEATURE, config.getRuntimeType()), JSON_FEATURE);

但此功能仅由该组件注册

org.玻璃鱼。泽西。杰克逊。内部。杰克逊汽车发现

if (!context.getConfiguration().isRegistered(JacksonFeature.class)) {
    context.register(JacksonFeature.class);
}

所以我所做的是注册我自己的功能，它注册了我自己的对象映射器提供程序，并放入一个绊线，阻止org.lassfish.jersey.jackson.JacksonFeature注册并覆盖我的对象映射程序。。。

import com.fasterxml.jackson.jaxrs.base.JsonMappingExceptionMapper;
import com.fasterxml.jackson.jaxrs.base.JsonParseExceptionMapper;

import org.glassfish.jersey.internal.InternalProperties;
import org.glassfish.jersey.internal.util.PropertiesHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.ws.rs.core.Configuration;
import javax.ws.rs.core.Feature;
import javax.ws.rs.core.FeatureContext;
import javax.ws.rs.ext.MessageBodyReader;
import javax.ws.rs.ext.MessageBodyWriter;

public class MarshallingFeature implements Feature {

    private final static String JSON_FEATURE = MarshallingFeature.class.getSimpleName();

    @Override
    public boolean configure(FeatureContext context) {

      context.register(JsonParseExceptionMapper.class);
      context.register(JsonMappingExceptionMapper.class);
      context.register(JacksonJsonProviderAtRest.class, MessageBodyReader.class, MessageBodyWriter.class);

      final Configuration config = context.getConfiguration();
      // Disables discoverability of org.glassfish.jersey.jackson.JacksonFeature
      context.property(
          PropertiesHelper.getPropertyNameForRuntime(InternalProperties.JSON_FEATURE,
                                                     config.getRuntimeType()), JSON_FEATURE);

      return true;
    }
}

这是自定义对象映射器提供程序。。。

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider;

import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.Provider;

@Provider
@Produces(MediaType.APPLICATION_JSON)
public class JacksonJsonProviderAtRest extends JacksonJaxbJsonProvider {

    private static ObjectMapper objectMapperAtRest = new ObjectMapper();

    static {
        objectMapperAtRest.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        objectMapperAtRest.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        objectMapperAtRest.configure(SerializationFeature.INDENT_OUTPUT, true); // Different from default so you can test it :)
        objectMapperAtRest.setSerializationInclusion(JsonInclude.Include.ALWAYS);
    }

    public JacksonJsonProviderAtRest() {
        super();
        setMapper(objectMapperAtRest);
    }
}

匿名用户

我找到了一个解决方案。我必须自己实例化Jackson Provider，并设置自定义的＜code＞ObjectMapper＜/code＞。在GitHub上可以找到一个工作示例：https://github.com/svenwltr/example-grizzly-jersey-jackson/tree/stackoverflow-answer

我删除了我的< code > ObjectMapperResolver 并修改了我的< code>main方法:

public class Main {
    public static void main(String[] args) {
        try {
            // create custom ObjectMapper
            ObjectMapper mapper = new ObjectMapper();
            mapper.enable(SerializationFeature.INDENT_OUTPUT);

            // create JsonProvider to provide custom ObjectMapper
            JacksonJaxbJsonProvider provider = new JacksonJaxbJsonProvider();
            provider.setMapper(mapper);

            // configure REST service
            ResourceConfig rc = new ResourceConfig();
            rc.register(ExampleResource.class);
            rc.register(provider);

            // create Grizzly instance and add handler
            HttpHandler handler = ContainerFactory.createContainer(
                    GrizzlyHttpContainer.class, rc);
            URI uri = new URI("http://0.0.0.0:8080/");
            HttpServer server = GrizzlyHttpServerFactory.createHttpServer(uri);
            ServerConfiguration config = server.getServerConfiguration();
            config.addHttpHandler(handler, "/");

            // start
            server.start();
            System.in.read();

        } catch (ProcessingException | URISyntaxException | IOException e) {
            throw new Error("Unable to create HTTP server.", e);
        }
    }
}

匿名用户

我是通过一点修补才弄明白这一点的。

问题似乎出在Jersey的功能自动检测机制上。如果您依赖Jersey来加载JacksonJaxbJsonProvider，那么ObjectMapper的自定义上下文提供程序将被忽略。相反，如果您手动注册该功能，它会起作用。我假设这与自动检测的提供程序被加载到不同的上下文范围有关，但对于解决方案，以下是我最终得到的结果。请注意，我将它封装到了一个功能中，您应该能够在没有问题的情况下直接向应用程序注册它。

public final class RequestMappingFeature implements Feature {

    @Override
    public boolean configure(final FeatureContext context) {

        context.register(ObjectMapperProvider.class);

        // If you comment out this line, it stops working.
        context.register(JacksonJaxbJsonProvider.class);

        return true;
    }
}

2017年11月更新：Jersey2世界的情况发生了一些变化。如果以上方法不起作用，请尝试以下操作：

提供您自己的对象映射器的新方法现在如下所示:

public final class JacksonFeature implements Feature {

    private static final ObjectMapper MAPPER;

    static {

        // Create the new object mapper.
        MAPPER = new ObjectMapper();

        // Enable/disable various configuration flags.
        MAPPER.configure(
                DeserializationFeature.READ_ENUMS_USING_TO_STRING, true);

        // ... Add your own configurations here.

    }
    @Override
    public boolean configure(final FeatureContext context) {
        JacksonJaxbJsonProvider provider = new JacksonJaxbJsonProvider(
                MAPPER, DEFAULT_ANNOTATIONS);
        context.register(provider);

        return true;
    }
}

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