泽西岛/ Tomcat-产生媒体冲突

Question

I am using a restful web service in which CRUD operations work, except for listing every single user on one page. The getUser() method is only used for logging into the webapp. I already took a look at this question, but I am not using named queries.

The error I am getting::

SEVERE: Producing media type conflict. The resource methods public ...UserResource.getUser() and ...UserResource.list() throws org.codehaus.jackson.JsonGenerationException,org.codehaus.jackson.map.JsonMappingException,java.io.IOException can produce the same media type

UserResource.list()

@GET
@Produces(MediaType.APPLICATION_JSON)
public String list() throws JsonGenerationException, JsonMappingException, IOException {
    this.logger.info("list()");

    ObjectWriter viewWriter;
    if (this.isAdmin()) {
        viewWriter = this.mapper.writerWithView(JsonViews.Admin.class);
    } else {
        viewWriter = this.mapper.writerWithView(JsonViews.User.class);
    }
    List<User> allEntries = this.userDao.findAll();

    return viewWriter.writeValueAsString(allEntries);
}

UserResource.getUser()

/**
 * Retrieves the currently logged in user.
 *
 * @return A transfer containing the username and the roles.
 */
@GET
@Produces(MediaType.APPLICATION_JSON)
public UserTransfer getUser() {
    Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
    Object principal = authentication.getPrincipal();
    if (principal instanceof String && ((String) principal).equals("anonymousUser")) {
        throw new WebApplicationException(401);
    }
    UserDetails userDetails = (UserDetails) principal;

    return new UserTransfer(userDetails.getUsername(), this.createRoleMap(userDetails));
}

Thanks in advance,

Answer 1

Your resources are to the same path, and there is nothing to differentiate them when Jersey needs to select a method (they have the same HTTP method, same path, same media type). The error is about media types, because it is completely possible to have two methods on the same path and HTTP method, just with different media types. This differentiates them

@GET
@Produces(MediaType.APPLICATION_XML)
public String list();

@GET
@Produces(MediaType.APPLICATION_JSON)
public String getUser();

But this it probably not what you want. So the solution is to just change the path on one of them

@GET
@Produces(MediaType.APPLICATION_JSON)
public String list();

@GET
@Path("/loggedInUser")
@Produces(MediaType.APPLICATION_JSON)
public String getUser();