尝试通过JAX-RS Web服务发送JSON对象,获取"找不到媒体类型= application/json的MessageBodyWriter"

Question

我试图通过JAX-RS Web服务发送JSON对象.我的文件web.xml是:

<servlet>
 <description>JAX-RS Tools Generated - Do not modify</description>
 <servlet-name>JAX-RS Servlet</servlet-name>
 <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
  <init-param>
<param-name>jersey.config.server.provider.packages</param-name>
<param-value>it.notifire</param-value>
  </init-param>
  <init-param>
<param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
<param-value>true</param-value>
  </init-param>
  <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
  <servlet-name>JAX-RS Servlet</servlet-name>
  <url-pattern>/jaxrs/*</url-pattern>
</servlet-mapping>

模拟我要发送的对象的类是:

public class GPSCoordinate {

private float latitudine;
private float longitudine;

 public float getLatitudine() {
    return latitudine;
}
public void setLatitudine(float latitudine) {
     this.latitudine = latitudine;
}
public float getLongitudine() {
    return longitudine;
}
public void setLongitudine(float longitudine) {
    this.longitudine = longitudine;
}
}

根类资源是:

@Path("position")
public class Position {

    @Context
private UriInfo context;

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public GPSCoordinate getHTML() {

        GPSCoordinate coord = new GPSCoordinate();
        coord.setLatitudine(90.45f);
        coord.setLongitudine(34.56f);

        return coord;
    }
}

现在,当我尝试访问该服务时,我将浏览器指向以下链接

http://localhost:8080/Notifire/jaxrs/position

我收到以下错误:

消息org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException:找不到媒体类型= application/json的MessageBodyWriter

在我的WEB-INF/lib文件夹中,我有最后一个版本的jersey JAX-RS实现(jaxrs-ri-2.5.jar)和jersey-json.jar存档.

任何帮助将非常感激.

Answer 1

尝试将Genson添加到类路径中,它将自动启用JSON支持.

Genson是json和java/scala的数据绑定和流式库.它实现了JAX-RS的扩展点MessageBodyReader/Writer,允许jersey自动检测Genson并将其用于Json解析/写入.

你可以找到更多关于Gensons与JaxRS(jersey&cie)整合的信息.

Answer 2

Jersey支持'autodiscoverable'功能,JSON支持就是其中之一.根据文档,为了启用它,您需要在路径中添加兼容的库

但是,虽然由于jersey-media-json-processing某种原因我的案例中没有识别推荐的库,但是jersey-media-moxy:

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-moxy</artifactId>
    <version>2.15</version>
</dependency>

2.15是撰写本文时的最新版本.访问maven central artifact页面以查找当前版本.

Answer 3

这就是我解决问题的方法。

用过杰克逊。添加了这些罐子

将此类添加到我的项目中。代码的关键行被标记为“重要”。

import com.fasterxml.jackson.jaxrs.json.JacksonJsonProvider; <-- IMPORTANT
import java.util.HashSet;
import java.util.Set;
import javax.ws.rs.core.Application;

//@javax.ws.rs.ApplicationPath("webresources")
public class MyApplicationConfig extends Application {

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

@Override
public Set<Object> getSingletons() {
    final Set<Object> instances = new HashSet<Object>();

    instances.add(new JacksonJsonProvider()); <--------- IMPORTANT
    return instances;
}
/**
 * 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(org.glassfish.jersey.media.multipart.MultiPartProperties.Feature.MultiPartContextResolver.class);
    //resources.add(org.glassfish.jersey.media.multipart.MultiPartProperties.Feature.MultiPartContextResolver.class);

}

}

Answer 4

向客户端配置注册JacksonJsonProvier类，然后创建Client对象，这对我有用。下面是代码。

    ClientConfig config = new ClientConfig();
    config.register(JacksonJsonProvider.class);
    Client client = ClientBuilder.newClient(config);