MessageBodyWriter not found for media type=application/json

问题:

I am facing issues while consuming JAX-RS services as JSON.

Below I have added my code.

This is my service class:

//Sets the path to base URL + /hello @Path("/hello")  @Consumes(MediaType.APPLICATION_JSON) @Produces(MediaType.APPLICATION_JSON) public class Hello {      @GET     @Produces("application/json")     public Student getStudent() {          Student s = new Student();         s.first_name = "Test First Name !!!";         s.last_name = "Test Last Name!!!";          return s;     } 

Student class which I am trying to get from service:

@XmlRootElement public class Student implements Serializable {      public String first_name;     public String last_name;      public String getFirst_name() {         return first_name;     }      public void setFirst_name(String first_name) {         this.first_name = first_name;     }      public String getLast_name() {         return last_name;     }      public void setLast_name(String last_name) {         this.last_name = last_name;     }      public Student()     {         first_name = "Fahad";         last_name = "Mullaji";     } } 

Web XML on service side.

com.vogella.jersey.firstJersey REST Serviceorg.glassfish.jersey.servlet.ServletContainerjersey.config.server.provider.packagescom.vogella.jersey.firstcom.sun.jersey.api.json.POJOMappingFeaturetrue1Jersey REST Service/rest/*

I don't know how to fix this issue. I am using SOAP UI for testing JSON response but I guess that it should not matter.

Many places I read that I need to add the code below. But I don't know where. I am not using Maven for building.

org.glassfish.jersey.mediajersey-media-moxy

Server is looking for function to parse Student object to JSON but it is not able to find function or jar file for it. I have added jar of Genson, Moxy, RESTEasy and Jackson but I think that's the problem. I think I am missing mapping somewhere.

回答1:

I was able to fix it by install jersey-media-json-jackson

Add the dependency to pom.xml

org.glassfish.jersey.mediajersey-media-json-jacksonruntime

回答2:

You've to create empty constructor because JAX-RS initializes the classes... Your constructor must have no arguments:

@XmlRootElement public class Student implements Serializable {      public String first_name;     public String last_name;      public String getFirst_name() {         return first_name;     }      public void setFirst_name(String first_name) {         this.first_name = first_name;     }      public String getLast_name() {         return last_name;     }      public void setLast_name(String last_name) {         this.last_name = last_name;     }      public Student()     {         first_name = "Fahad";         last_name = "Mullaji";     }    public Student()     {     } } 

回答3:

I was in the same situation where
- I was not using Maven or Ant,
- I finished this Vogella tutorial on Jersey,
- and I was getting the MessageBodyWriter error when trying to use @Produces(MediaType.APPLICATION_JSON).

This answer by @peeskillet solves the problem - you have to use the Jackson *.jar files that are available from the FasterXML Jackson Download page. You'll need the core files as well as the jaxrs files.

I added them to my WebContent/WEB-INF/lib folder where I have my Jersey *.jar files per the above tutorial, and made the small change to the web.xml file below (again, as originally shared by @peeskillet):

jersey.config.server.provider.packages     your.other.package.here, com.fasterxml.jackson.jaxrs.json  

The important part being com.fasterxml.jackson.jaxrs.json.

回答4:

Uncommenting the below code helped

org.glassfish.jersey.mediajersey-media-moxy

which was present in pom.xml in my maven based project resolved this error for me.

回答5:

Well, I could not make the above web project working. But I kept on doing research on JAX-RS and I came across Stormpath's tutorial. I think whoever is trying to learn how REST, JSON and Jersey work together should watch this.

Please see links below for their presentation and sample REST project on GitHub .

https://www.youtube.com/watch?v=sVvL12BnIyQ

https://github.com/stormpath/todos-jersey

Now I can compare above project and see what all things I did wrong.

回答6:

Below should be in your pom.xml above other jersy/jackson dependencies. In my case it as below jersy-client dep-cy and i got MessageBodyWriter not found for media type=application/json.

org.glassfish.jersey.mediajersey-media-json-jackson2.25

回答7:

I think may be you should try to convert the data to json format. It can be done by using gson lib. Try something like below.

I don't know it is a best solutions or not but you could do it this way.It worked for me

example : `

@GET @Produces({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON }) public Response info(@HeaderParam("Accept") String accept) {     Info information = new Info();     information.setInfo("Calc Application Info");     System.out.println(accept);     if (!accept.equals(MediaType.APPLICATION_JSON)) {         return Response.status(Status.ACCEPTED).entity(information).build();     } else {         Gson jsonConverter = new GsonBuilder().create();         return Response.status(Status.ACCEPTED).entity(jsonConverter.toJson(information)).build();     } } 

回答8:

I faced a similar problem because the constructor of this object was using parameters

Before

public MakeMoneyAndGetFitWhileYouSleep(@NotNull UserDetails turkey) {...} 

After

public MakeMoneyAndGetFitWhileYouSleep(){}  public static MakeMoneyAndGetFitWhileYouSleep getInstance (@NotNull UserDetails turkey) {...} 

回答9:

To overcome this issue try the following. Worked for me.

Add following dependency in the pom.xml

org.glassfish.jersey.mediajersey-media-json-jackson2.25

And make sure Model class contains no arg constructor

 public Student()     {     } 

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