beerye beerye - 3 months ago 33
JSON Question

Error parsing JSON param in java REST

I have recently upgraded my REST API to use jersey 2.x and now I am unable to retrieve JSON body params the way I used to, the methods simply do not get called anymore. My guess is I'm missing a dependency to parse the JSON to a java object but I'm not too sure what i need to add in, any help appreciated.

pom.xml

<dependencies>
<dependency>
<groupId>javax.ws.rs</groupId>
<artifactId>javax.ws.rs-api</artifactId>
<version>2.0.1</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-servlet</artifactId>
<version>2.19</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.core</groupId>
<artifactId>jersey-server</artifactId>
<version>2.19</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.core</groupId>
<artifactId>jersey-client</artifactId>
<version>2.19</version>
</dependency>
<dependency>
<groupId>com.googlecode.json-simple</groupId>
<artifactId>json-simple</artifactId>
<version>1.1.1</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-multipart</artifactId>
<version>2.22</version>
</dependency>
</dependencies>


REST method

@POST
@Path("/users/{userId}/friends")
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public Response followUser(@PathParam("userId") Integer myUserId, FollowUserBean user) {}


FollowUserBean.java

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class FollowUserBean {
public Integer friendId;

public FollowUserBean() {}
}

Answer

You need a JSON provider. At time of writing, Jersey integrates with the following modules to provide JSON support:

To use Jackson 2.x as your JSON provider you need to add jersey-media-json-jackson module to your pom.xml file:

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-json-jackson</artifactId>
    <version>2.23.1</version>
</dependency>

To use Jackson 1.x it'll look like:

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-json-jackson1</artifactId>
    <version>2.23.1</version>
</dependency>

Besided adding the dependency mentioned above, you need to register JacksonFeature (or Jackson1Feature for Jackson 1.x) in your Application/ResourceConfig sub-class.

For more details, check the Jersey documentation about support for common media type representations.