为什么我的参数没有传递到RESTful Web服务？

Question

I have this code using Angular 4 HttpClient , supposed to communicate with a simple RESTful JAVA web service and get a JSON string back:

this.client.post('http://localhost:8080/ToDoService/rest/service/create', {id: 'foo', todo: 'bar'}).subscribe((data) => {
    console.log("Got data: ", data);
}, (error) => {
    console.log("Error", error);           
})

It's not working. What I mean is that the id and todo parameters are not getting passed to the REST backend.

At the other hand, if I change above code to:

this.client.post('http://localhost:8080/ToDoService/rest/service/create?id=foo&todo=bar', '').subscribe((data) => {
    console.log("Got data: ", data);
}, (error) => {
    console.log("Error", error);           
})

Everything works fine, but I'm sure the second snipped is wrong. It just looks wrong.

Could you give me a push and point my mistake?

Ps

The JAVA backend:

@Path("/service")
public class Rest extends Application{
    @POST
    @Path("/create")
        public Response printMessage(@QueryParam("id") String userId, @QueryParam("todo") String toDo) {
            JSONObject result = new JSONObject();

            result.put("id", userId);
            result.put("todo", toDo);

            return Response.status(200).entity(result.toString()).build();
        }
}

Answer 1

You're mapping QueryParams, you need to map that payload to either a Map or an Object:

class PayLoad {
    private String id;
    private String todo;
    // Getter and Setters
}

@Path("/service")
public class Rest extends Application{
    @POST
    @Path("/create")
        public Response printMessage(@RequestBody PayLoad payload) {
            JSONObject result = new JSONObject();

            result.put("id", payload.getId());
            result.put("todo", payload.getTodo());

            return Response.status(200).entity(result.toString()).build();
        }
}

Hope this helps!

Answer 2

First of all, looking at the MyKong tutorial you can see that @QueryParam accepts parameters sent in the URL . That is a first problem here. Back to the main point.

---

I am not an expert in Angular 4, but I think the problem lies deeper in your architecture. You are sending to your backend:

{id: 'foo', todo: 'bar'}

and expect in your Java:

@QueryParam("id") String userId, @QueryParam("todo") String toDo

You pass an object and expect in your Java backend two strings . If you want to get your object, you might create this kind of class:

public class JsonWrapper    {
    private String id;
    private String todo;

 // Classic constructor and setters
}

Then, in your service:

@Path("/service")
public class Rest extends Application    {
    @POST
    @Path("/create")
    public Response printMessage(@RequestBody JsonWrapper wrapper) {
        JSONObject result = new JSONObject();

        result.put("id", wrapper.getId());
        result.put("todo", wrapper.getTodo());

        return Response.status(200).entity(result.toString()).build();
    }
}

If the JsonWrapper does not work, I think a Map can do the trick, too.