Jersey JSON serialization

Question

I set up an eclipse WebApp project and placed Jersey and Jackson JARs in the WEB-INF/lib directory. I want to use JSON serialization but didn\'t manage to fix this error:

Answer 1

Have you tried adding this to your web.xml?

<init-param>
    <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
    <param-value>true</param-value>
</init-param>

I believe this tutorial shows what you are trying yo do http://examples.javacodegeeks.com/enterprise-java/rest/jersey/json-example-with-jersey-jackson/

Another one from mkyong http://www.mkyong.com/webservices/jax-rs/json-example-with-jersey-jackson/

Answer 2

All you need is to register JacksonJsonProvider. There are many ways to achieve that:

1. Register the JacksonJsonProvider explicitly in web.xml:

<init-param>
    <param-name>jersey.config.server.provider.classnames</param-name>
    <param-value>com.fasterxml.jackson.jaxrs.json.JacksonJsonProvider</param-value>
</init-param>

or

2. Register your class extending javax.ws.rs.core.Application in the web.xml

<init-param>
    <param-name>javax.ws.rs.Application</param-name>
    <param-value>com.rest.MyApplication</param-value>
</init-param>

and then do all the configuration in the application class:

package com.rest;

import org.glassfish.jersey.server.ResourceConfig;
import com.fasterxml.jackson.jaxrs.json.JacksonJsonProvider;

public class MyApplication extends ResourceConfig {

    public MyApplication() {
        packages("com.rest");
        register(JacksonJsonProvider.class);
    }

ResourceConfig is a subclass of javax.ws.rs.Application and gives you some helper methods that makes the registration easy.

or

3. Use automatic registration. Just add dependency to jersey-media-json-jackson

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-json-jackson</artifactId>
    <version>2.13</version>
</dependency>

But be careful. It will register more than you need:

• JacksonJaxbJsonProvider,
• JsonParseExceptionMapper,
• JsonMappingExceptionMapper

Take a look at the source code to see what it does.