415 unsupported media type + spring

Question

The problem:
I'm trying to send a request as a POST with to parameters: {id: 20, roleName: "ADMIN"} and getting this error (415 unsupported media type).

Framework:
Spring 4.1.1

In my @Controller in server side, I have the following:

@RequestMapping("/role/add.action")
    @ResponseBody
    public Map<String,Object> addrole(@RequestBody Role role, 
            HttpServletRequest request,
            Authentication authentication,
            HttpServletResponse response) {
    //Code goes here..
}

This --> @RequestBody Role role works fine for any other type of object but, for Role I get this issue.

My Role class is:

@Entity
public class Role implements Serializable{


    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    @Id
    private int id;

    @Column
    private String roleName;

    @Fetch(FetchMode.SELECT)
    @OneToMany(mappedBy = "role", targetEntity = Users.class, fetch = FetchType.EAGER)
    @JsonManagedReference(value="role")
    private List<Users> users = new LinkedList<Users>();

    @Fetch(FetchMode.SELECT)
    @ManyToMany(fetch=FetchType.EAGER)
    @JoinTable(name="role_features",
            joinColumns=@JoinColumn(name="roleId"),
            inverseJoinColumns=@JoinColumn(name="featureId"))
    @OrderBy(clause="featureId")
    private Set<SystemFeature> features = new HashSet<SystemFeature>();

    @Fetch(FetchMode.SELECT)
    @ManyToMany(fetch=FetchType.EAGER)
    @JoinTable(name="role_menu",
            joinColumns=@JoinColumn(name="roleId"),
            inverseJoinColumns=@JoinColumn(name="menuId"))
    @OrderBy(clause="menuId")
    private Set<Menu> menus = new HashSet<Menu>();

    @Fetch(FetchMode.SELECT)
    @ManyToMany(fetch=FetchType.EAGER)
    @JoinTable(name="role_services_stations",
            joinColumns=@JoinColumn(name="roleId"),
            inverseJoinColumns=@JoinColumn(name="stationId"))
    @OrderBy(clause="stationId")
    private Set<ServiceStation> stations = new HashSet<ServiceStation>();

    //Constructors, getters and setters...

}

This class has java.util.Set attributes, and I think that this may causing the problem.

I'm sending just two properties: id and roleName. The cast should work, right?

PS: I've set a Jackson message-converter bean already, but didn't work.

    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean
                class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="com.fasterxml.jackson.databind.ObjectMapper">
                        <property name="serializationInclusion">
                            <value type="com.fasterxml.jackson.annotation.JsonInclude.Include">NON_NULL</value>
                        </property>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

Someone could help me? xD

Answer 1

My problem was basically on @JsonManagedReference annotation.

What I did:

1) I changed my payload to a Map:

public Map<String,Object> addRole(@RequestBody Map payload, 
            HttpServletRequest request,
            Authentication authentication,
            HttpServletResponse response) {
...
}

2) Then I tried to cast it with Jackson's ObjectMapper (com.fasterxml.jackson.databind.ObjectMapper):

ObjectMapper mapper = new ObjectMapper();

Role role = mapper.convertValue(payload, Role.class);

Then the debugger threw me an exception:

java.lang.IllegalArgumentException: Can not handle managed/back reference 'parent': no back reference property found from type [collection type; class java.util.Set, contains [simple type, class br.com.ttrans.samapp.model.Menu]]

This exception helped find the problem, that (in my case) was the annotation @JsonManagedReference. From docs:

Annotation used to indicate that annotated property is part of two-way linkage between fields; and that its role is "parent" (or "forward") link. Value type (class) of property must have a single compatible property annotated with JsonBackReference. Linkage is handled such that the property annotated with this annotation is handled normally (serialized normally, no special handling for deserialization); it is the matching back reference that requires special handling

This is used for two-way linkage and my payload was coming one-way. So..

3) ...I removed @JsonManagedReference's annotations and kept only @JsonBackReference in all nested classes;

Then the debbuger threw me another exception, but this time was: java.lang.IllegalArgumentException: Unrecognized field ... so putting @JsonIgnoreProperties(ignoreUnknown = true) on all classes solved my problem.

So after all that I could receive the payload already parsed as Role:

@RequestMapping("/role/add.action")
@ResponseBody
public Map<String,Object> addRole(@RequestBody Role role, 
            HttpServletRequest request,
            Authentication authentication,
            HttpServletResponse response) {

            ...
}

Hope it helps!

Answer 2

dont use both @JsonBackReference and @JsonManagedReference. remove only@JsonManagedReference annotation. it worked for me

Answer 3

This is clearly due to ManyToMany associations (like features,menus etc). Modify such that it breaks the json chain, may be adding @JsonIgnore at suitable places will solve it.