Why object to json conversion using spring MVC doesn't work in this case?

Question

I need to execute this URL: http://localhost:8080/FitiProject/student and the response needs to be a json string containing the data of a Student object.

Here is my code:

package spring.controllers;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import model.Student;

@Controller
public class PruebaController {
    @RequestMapping("/student")
    public @ResponseBody Student getStudent(){
        return new Student(2, "h");
    }
}

This is Student.java

package model;

public class Student {
    private int edad;
    private String nombre;

    public Student(int edad, String nombre) {
        super();
        this.edad = edad;
        this.nombre = nombre;
    }

    public int getEdad() {
        return edad;
    }
    public void setEdad(int edad) {
        this.edad = edad;
    }
    public String getNombre() {
        return nombre;
    }
    public void setNombre(String nombre) {
        this.nombre = nombre;
    }
}

When I do a GET request on the URL, I don't get a JSON response instead I get a 406 error code. How can I solve this?

I'm using Jackson 1.9 and Spring 4.1.

Estado HTTP 406 -

type Informe de estado

mensaje

descripción El recurso identificado por este requerimiento sólo es capaz de generar respuestas con características no aceptables con arreglo a las cabeceras "accept" de requerimiento. — Federico Portillo, Feb 01 '16 at 15:30

score 2 · Accepted Answer · answered Feb 01 '16 at 14:45

2

Your getStudent method lacks the content type of the response, otherwise Spring won't know to which format convert the Student. This can be done by using produces attribute in @RequestMapping.

//"produces" will tell Spring to which format convert the data
//"method" will tell Spring which HTTP method should be handled for this URL
@RequestMapping(value="/student",
    produces="application/json; charset=UTF-8",
    method=RequestMethod.GET)
public @ResponseBody Student getStudent(){
    return new Student(2, "h");
}

When executing a request to your URL, make sure that the client uses the following header: Content-Type: application/json

It's worth to mention that your project needs to have jackson libraries in order to work.

answered Feb 01 '16 at 14:45

Luiggi Mendoza

85,076
16
154
332

1

Error 406 :/ i cant get the json, just get a response with error. – Federico Portillo Feb 01 '16 at 15:29
Which version of Spring and Jackson are you using? – Luiggi Mendoza Feb 01 '16 at 15:31
4.1.1.RELEASE – Federico Portillo Feb 01 '16 at 15:35
org.codehaus.jackson jackson-mapper-asl 1.9.10 – Federico Portillo Feb 01 '16 at 15:35
For Spring 4, you should use Jackson 2.x as shown [here](http://stackoverflow.com/a/27767809/1065197). Also, make sure your client accepts `application/json` as well. – Luiggi Mendoza Feb 01 '16 at 15:37
Hablas español? estoy usando soapUI para probar. – Federico Portillo Feb 01 '16 at 15:38
Yes I do but in this site we communicate using English. If you want to communicate using Spanish, then you can post (or migrate maybe) your question to [StackOverflow en español](http://es.stackoverflow.com/) – Luiggi Mendoza Feb 01 '16 at 15:39
When is it necessary to set the produces?? – codeMan Feb 01 '16 at 16:00
Does it not consider "application/json" as the content type by default ? – codeMan Feb 02 '16 at 08:13
1

@codeMan please refer to [this answer](http://stackoverflow.com/a/28647129/1065197) – Luiggi Mendoza Feb 02 '16 at 13:05
@LuiggiMendoza Thanks. This is something I that learned newly today. – codeMan Feb 04 '16 at 10:46

score 1 · Answer 2 · answered Feb 01 '16 at 14:47

1

If you're already using Jackson, you could try using the ObjectMapper class:

ObjectMapper mapper = new ObjectMapper();
System.out.println("Object in JSON:\n" + mapper.writerWithDefaultPrettyPrinter().writeValueAsString(object));

answered Feb 01 '16 at 14:47

jste89

426
4
15

Spring can handle this conversion for you – Luiggi Mendoza Feb 01 '16 at 14:47
This was just an alternate solution which could be used to solve the problem. It wouldn't be my choice, but I had an example to hand so I thought I would share it. – jste89 Feb 01 '16 at 14:49

score 0 · Answer 3 · answered Feb 01 '16 at 14:40

Since you are using @ResponseBody annotation the response will be automatically converted to JSON. Make sure you include jackson mapper library in your class path.

If you are using Maven, you can add the jackson dependency as follows :

<dependency>  
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-mapper-asl</artifactId>
    <version>1.8.2</version>
</dependency>

<dependency>  
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-core-asl</artifactId>
    <version>1.8.2</version>
</dependency>

score 0 · Answer 4 · answered Feb 01 '16 at 14:52

0

Use the RestController : org.springframework.web.bind.annotation.RestController to get automatic conversion of the responseBody into a JSON Format.

answered Feb 01 '16 at 14:52

Ashoka

935
7
20

Why object to json conversion using spring MVC doesn't work in this case?

4 Answers4