带有 Jersey 2.2 和 Jackson 2.1 的自定义 ObjectMapper

Question

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

POM 依赖：

<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>

产生的版本是：Grizzly 2.3.3、Jackson 2.1.4 和 Jersey 2.2。

主类（我想要显式注册 Jersey 组件）：

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);
        }
    }
}

ObjectMapper 的上下文解析器：

@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;
    }

}

ObjectMapperResolver 构造函数和 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，因为它是另一个库的依赖项。

完整的例子可以在 GitHub 上找到：https://github.com/svenwltr/example-grizzly-jersey-jackson/tree/stackoverflow

Answer 1

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）

泽西 2.12，杰克逊 2.4.x

我将我的消息与我在这篇文章中提出的解决方案一起添加，因为它与我今天输入的许多 Google 搜索非常相关......对于我所相信的而言，这是一个繁琐的解决方案成为一个更麻烦的问题。

1。确保您的 maven 配置包含 jackson-jaxrs-json-provider 依赖项：

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

2。确保您的 Maven 配置不包含 jersey-media-json-jackson 依赖项：

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

3。创建一个扩展com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider 的@Provider 组件，如下所示：

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.fasterxml.jackson.databind.ObjectMapper 的自定义实例的地方

4。像这样通过MarshallingFeature 扩展javax.ws.rs.core.Feature：

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;
    }
}

5。您需要像这样注册此自定义提供程序，前提是您通过 org.glassfish.jersey.server.ResourceConfig 像这样配置您的应用程序：

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.Response 包装控制器的响应，此解决方案都适用。
2. 请确保您仔细考虑（复制/粘贴）以下代码 sn-ps，因为唯一的“非强制性”可以说是与 com.fasterxml.jackson.databind.ObjectMapper 的自定义配置有关的位。

@jcreason

很抱歉，@jcreason 把球丢在了这个上面，我希望你仍然是古玩。 所以我检查了去年的代码，这就是我想出的提供自定义映射器的方法。

问题在于，在功能初始化期间，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);

但是这个特性只能被这个组件注册

org.glassfish.jersey.jackson.internal.JacksonAutoDiscoverable

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，该功能注册我自己的对象映射器提供程序并放入绊线停止 org.glassfish.jersey.jackson.JacksonFeature 被注册并覆盖我的对象映射器......

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);
    }
}

Answer 2

我找到了解决方案。我必须自己实例化 Jackson Provider 并设置我的自定义 ObjectMapper。可以在 GitHub 上找到一个工作示例：https://github.com/svenwltr/example-grizzly-jersey-jackson/tree/stackoverflow-answer

我删除了我的ObjectMapperResolver 并修改了我的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);
        }
    }
}

Answer 3

我想通了，基于一些修补。

问题似乎出在 Jersey 的功能自动检测机制中。如果您依赖 Jersey 加载 JacksonJaxbJsonProvider，则您的 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，它就可以工作。我假设这与将自动检测到的提供程序加载到不同的上下文范围有关，但至于解决方案，这就是我最终得到的。请注意，我将它包装成一个功能，您应该可以直接在您的应用程序中注册它而不会出现问题。

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 世界发生了一些变化。如果上述方法不起作用，请尝试以下操作：

提供您自己的 ObjectMapper 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;
    }
}

Answer 4

请这样做：

1) 添加 pom.xml 依赖

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-json-jackson</artifactId>
    <version>2.2</version>
</dependency>

2) 在 Main.java 中注册 JacksonFeature

public class Main {

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

3) 在您的资源中使用 org.codehaus.jackson.map.ObjectMapper

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

import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig.Feature;

@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(Feature.INDENT_OUTPUT);
    }

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

Answer 5

由于我花了几个小时才将它与 Java EE7 和 Glassfish4 一起使用，所以这是我的解决方案：

@javax.ws.rs.ApplicationPath("withJackson")
public class ApplicationConfig extends Application {

    private static final Logger log = java.util.logging.Logger.getLogger(ApplicationConfig.class.getName());

    @Override
    public Set<Object> getSingletons() {
        Set<Object> set = new HashSet<>();
        log.log(Level.INFO, "Enabling custom Jackson JSON provider");
        set.add(new JacksonJsonProvider().configure(SerializationFeature.INDENT_OUTPUT, true));
        return set;
    }

    @Override
    public Map<String, Object> getProperties() {
        Map<String, Object> map = new HashMap<>();
        log.log(Level.INFO, "Disabling MOXy JSON provider");
        map.put("jersey.config.disableMoxyJson.server", true);
        return map;
    }

    @Override
public Set<Class<?>> getClasses() {
    Set<Class<?>> resources = new java.util.HashSet<>();
    addRestResourceClasses(resources);
    return resources;
}

/**
 * Do not modify addRestResourceClasses() method.
 * It is automatically populated with
 * all resources defined in the project.
 * If required, comment out calling this method in getClasses().
 */
private void addRestResourceClasses(Set<Class<?>> resources) {
    resources.add(com.fasterxml.jackson.jaxrs.base.JsonMappingExceptionMapper.class);
    resources.add(com.fasterxml.jackson.jaxrs.base.JsonParseExceptionMapper.class);
    resources.add(com.fasterxml.jackson.jaxrs.json.JsonMappingExceptionMapper.class);
    resources.add(com.fasterxml.jackson.jaxrs.json.JsonParseExceptionMapper.class);
    resources.add(de.lathspell.java_test_ee7_json.Api.class);
    resources.add(de.lathspell.java_test_ee7_json.with_jackson.MyExceptionMapper.class);
}

唯一相关的 POM 依赖项是：

    <dependency>
        <groupId>com.fasterxml.jackson.jaxrs</groupId>
        <artifactId>jackson-jaxrs-json-provider</artifactId>
        <version>2.2.3</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.2.3</version>
    </dependency>

    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-web-api</artifactId>
        <version>7.0</version>
        <scope>provided</scope>
    </dependency>

Answer 6

来自 Jersey 2.17 文档： https://eclipse-ee4j.github.io/jersey.github.io/documentation/2.17/media.html#jackson-registration

在应用程序中

@ApplicationPath("/")
public class MyApplication extends ResourceConfig {
  public MyApplication() {
    register(JacksonFeature.class);
    // This is the class that you supply, Call it what you want
    register(JacksonObjectMapperProvider.class);
    //...
  }
}

编辑，忘记添加您在 register(..) 中提供的 JacksonObjectMapperProvider：

import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;

@Provider
public class JacksonObjectMapperProvider implements ContextResolver<ObjectMapper>{
  final ObjectMapper defaultObjectMapper;

  public JacksonObjectMapperProvider() {
     defaultObjectMapper = createDefaultMapper();
  }

  @Override
  public ObjectMapper getContext(Class<?> type) {return defaultObjectMapper;}

   public static ObjectMapper createDefaultMapper() {
      final ObjectMapper jackson = new ObjectMapper();
      // any changes to the ObjectMapper is up to you. Do what you like.
      // The ParameterNamesModule is optional,
      // it enables you to have immutable POJOs in java8
      jackson.registerModule(new ParameterNamesModule());
      jackson.enable(SerializationFeature.INDENT_OUTPUT);
      jackson.disable(SerializationFeature.WRITE_EMPTY_JSON_ARRAYS);
      jackson.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
      return jackson;
   }
}

Answer 7

使用 Jackson 2.7，这不起作用：

public class MyApplication extends ResourceConfig {
    public MyApplication() {
    register(MyObjectMapperProvider.class);
}}

调用了 MyObjectMapperProvider 构造函数，但从未调用过 getContext()。

在 super() 构造函数中注册 MyObjectMapperProvider 使其工作：

public class MyApplication extends ResourceConfig {
   public MyApplication() {
       super(
            // register Jackson ObjectMapper resolver
            MyObjectMapperProvider.class
       );
}}

见this Jersey example code。