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带有 Jersey 2.2 和 Jackson 2.1 的自定义 ObjectMapper

[英]Custom ObjectMapper with Jersey 2.2 and Jackson 2.1

 原文  2013-09-18 12:58:49  1   7    java/ jersey/ jackson/ jax-rs/ jersey-2.0

问题描述

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>

结果版本是：Grizzly 2.3.3、Jackson 2.1.4 和 Jersey 2.2。

主类（我想显式注册 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 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;
    }

}

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。

完整示例可以在 GitHub 上找到： https : //github.com/svenwltr/example-grizzly-jersey-jackson/tree/stackoverflow

7 个解决方案

解决方案1
 45  2015-05-06 16:16:27

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

我正在添加我的消息以及我在这篇文章中提出的解决方案，因为它与我今天进行的许多 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， com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider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);
    }
}

正如您所观察到的，这也是我们定义com.fasterxml.jackson.databind.ObjectMapper的自定义实例的com.fasterxml.jackson.databind.ObjectMapper

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

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. 您需要像这样注册这个自定义提供程序，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);
        ...
     }
 }

其他注意事项和观察：

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

@jcreason

很抱歉把球丢在这个@jcreason 上，我希望你仍然是好奇心。 所以我检查了去年的代码，这就是我提供自定义映射器的想法。

问题是在特性初始化期间，任何自定义对象映射器都会被某些代码禁用

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);

但是这个功能只会被这个组件注册

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，该功能注册了我自己的对象映射器提供程序，并在绊线中阻止 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);
    }
}

解决方案2
 34 已采纳  2013-09-20 13:22:00

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);
        }
    }
}

解决方案3
 9  2014-03-03 16:57:21

我想通了这一点，基于一点修补。

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，那么您的 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，则它可以工作。 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，我将它封装到一个功能中，您应该可以毫无问题地直接在您的应用程序中注册它。

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 的新方法现在看起来像这样：

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;
    }
}

解决方案4
 8  2013-09-18 23:06:49

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) 在你的资源中使用 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;
    }
}

解决方案5
 7  2014-04-02 02:57:47

由于我花了几个小时才能使用 Java EE7 和 Glassfish4，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>

解决方案6
 7  2015-05-10 22:19:07

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

在申请中

@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;
   }
}

解决方案7
 2  2016-04-08 20:17:57

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
       );
}}

请参阅此 Jersey 示例代码。

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