spring mvc not returning json content - error 406

Question

I am using Spring MVC with JSON as specified in Ajax Simplification Spring 3.0 article.

After so many attempts and variations of my code depending on advice found on various forums, my code still doesn't work.

I keep on getting the following error: (406) The resource identified by this request is only capable of generating responses with characteristics not acceptable according to the request "accept" headers ().

I have in my appconfig.xml as required.

app-config.xml

    <context:component-scan base-package="org.ajaxjavadojo" />

    <!-- Configures Spring MVC -->
    <import resource="mvc-config.xml" />

mvc-config.xml

<mvc:annotation-driven />

<!-- Forwards requests to the "/" resource to the "index" view -->
<mvc:view-controller path="/" view-name="index"/>


<!-- Resolves view names to protected .jsp resources within the /WEB-INF/views directory -->
<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
<property name="mediaTypes">
<map>
  <entry key="html" value="text/html"/>
  <entry key="json" value="application/json"/>
</map>
</property>
<property name="viewResolvers">
<list>
  <bean class="org.springframework.web.servlet.view.BeanNameViewResolver"/>
  <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/views/"/>
    <property name="suffix" value=".jsp"/>
  </bean>
</list>
</property>

</bean>

This is what I have for my controller

@Controller
@RequestMapping (value = "/convert")
public class ConversionController {

  @RequestMapping(method=RequestMethod.GET)
  public String getConversionForm(){
    return "convertView";
  }

  @RequestMapping(value = "/working", headers="Accept=application/json", method=RequestMethod.GET)
  public @ResponseBody Conversion getConversion(){
    Conversion d = new Conversion("d");
    return d;
  }
}

jsp jquery call

  function convertToDecimal(){
    $.getJSON("convert/working", {key: "r"}, function(aConversion){
      alert("it worked.");
      $('#decimal').val(aConversion.input);
    });
  }

I would really appreciate any input on this issue. Thank you

Answer 1

To return JSON response from @ResponseBody-annotated method, you need two things:

• <mvc:annotation-driven /> (you already have it)
• Jackson JSON Mapper in the classpath

You don't need ContentNegotiatingViewResolver and headers in @RequestMapping.

Answer 2

I had this problem after I upgraded Spring to 4.1.x from 3.2.x. I fixed by upgrading Jackson from 1.9.x to 2.2.x (fasterxml)

 <dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.2.3</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.2.3</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.2.3</version>
</dependency>

Answer 3

Try remove the header limitation for Accept, put a breakpoint and see what's the actual value. Or do this with FireBug.

Also take a look at this jquery issue

Answer 4

Add org.springframework.http.converter.json.MappingJacksonHttpMessageConverter and org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter to DispatcherServlet-servlet.xml. and refer to the the first one in the second using

<bean id="jacksonMessageConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"></bean>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="messageConverters">
        <list>
            <ref bean="jacksonMessageConverter"/>
        </list>
    </property>
</bean>

Answer 5

I too got this error and while debugging deep down into the rabbit hole i came across this exception

java.lang.IllegalArgumentException: Conflicting getter definitions for property "error": com.mycomp.model.OutputJsonModel#isError(0 params) vs com.mycomp.model.OutputJsonModel#getError(0 params)

So basically in my java bean i had something like the following:

private boolean isError;
private ErrorModel error;

public ErrorModel getError() {
return error;
}

public void setError(ErrorModel error) {
this.error = error;
}
public boolean isError() {
return isError;
}

public void setError(boolean isError) {
this.isError = isError;
}

Changing one of the error member variable name to something else solved the issues.