Java - Casting JSON à ressource en appel reste - Stack Overflow

I'm trying to accept JSON input from a POST and automatically cast it to the resource class, but I keep getting the error:

java.lang.ClassCastException: com.foo.MyResource cannot be cast to java.util.Collection

I thought I annotated my class correctly, but I feel like I'm missing something obvious. Can anyone help me figure out why this code will not parse the below JSON into a MyResource object?

My service class contains this method:

@POST
@Path("/somepath/{user}")
@Consumes(MediaType.APPLICATION_JSON)
public String createUser(MyResource resource, @PathParam("user") String user){
    return "Got resource " + resource + " for " + user;
}

The resource is as follows:

@XmlRootElement 
@XmlAccessorType(XmlAccessType.FIELD) 
public class MyResource {
    public String foo;
    public String bar;
    public int baz;
    public String toString(){
        return foo + " " + bar + " " + baz;
    } }

My request message:

Headers:
Content-Length: 92
Host: requestb.in
Cache-Control: no-cache
Accept-Encoding: gzip,deflate,sdch
Content-Type: application/json
Connection: close
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.154 Safari/537.36
Accept: */*
Cookie: session=eyJyZWNlbnQiOlsiMTZwcXV1NDEiXX0.BiBTRw.qNeCDkVfl-4Xog8hLhYuJFSlEYg; _ga=GA1.2.1701494324.1396374352
X-Request-Id: c9bd3f19-f071-47ad-9adb-d98232a7e8fb
Origin: chrome-extension://fdmmgilgnpjigdojojpjoooidkmcomcm
Accept-Language: en-US,en;q=0.8

RAW BODY

    [
      {
        "foo": "foo string"
      }, 
      {
        "bar": "bar string"
      }, 
      {
        "baz": 5
      }
    ]

The object you send is not is the right format :

You should send

{
   "foo": "foo string",
   "bar": "bar string",
   "baz": 5
}

In fact the object you are sending is an array [] of objects {}. That's why there is a cast problem.

I'm trying to accept JSON input from a POST and automatically cast it to the resource class, but I keep getting the error:

java.lang.ClassCastException: com.foo.MyResource cannot be cast to java.util.Collection

I thought I annotated my class correctly, but I feel like I'm missing something obvious. Can anyone help me figure out why this code will not parse the below JSON into a MyResource object?

My service class contains this method:

@POST
@Path("/somepath/{user}")
@Consumes(MediaType.APPLICATION_JSON)
public String createUser(MyResource resource, @PathParam("user") String user){
    return "Got resource " + resource + " for " + user;
}

The resource is as follows:

@XmlRootElement 
@XmlAccessorType(XmlAccessType.FIELD) 
public class MyResource {
    public String foo;
    public String bar;
    public int baz;
    public String toString(){
        return foo + " " + bar + " " + baz;
    } }

My request message:

Headers:
Content-Length: 92
Host: requestb.in
Cache-Control: no-cache
Accept-Encoding: gzip,deflate,sdch
Content-Type: application/json
Connection: close
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.154 Safari/537.36
Accept: */*
Cookie: session=eyJyZWNlbnQiOlsiMTZwcXV1NDEiXX0.BiBTRw.qNeCDkVfl-4Xog8hLhYuJFSlEYg; _ga=GA1.2.1701494324.1396374352
X-Request-Id: c9bd3f19-f071-47ad-9adb-d98232a7e8fb
Origin: chrome-extension://fdmmgilgnpjigdojojpjoooidkmcomcm
Accept-Language: en-US,en;q=0.8

RAW BODY

    [
      {
        "foo": "foo string"
      }, 
      {
        "bar": "bar string"
      }, 
      {
        "baz": 5
      }
    ]

The object you send is not is the right format :

You should send

{
   "foo": "foo string",
   "bar": "bar string",
   "baz": 5
}

In fact the object you are sending is an array [] of objects {}. That's why there is a cast problem.

Source