Elad Benda2 Elad Benda2 - 2 months ago 14
JSON Question

how come `.readEntity(MyObj.class)` fails while `objectMapper.readValue(str, MyObj.class);` works

I have this code

import javax.ws.rs.core.GenericType;
import javax.ws.rs.core.MediaType;
import java.io.InputStream;

import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
import java.util.Map;
/**
* Created by eladb on 9/6/16.
*/
public class DeploymentClient {

private CommonClient commonClient;


String appName = "topic-test-publisher";


public DeploymentClient(String url, InputStream clientSecretFile) {
commonClient = new CommonClient(url, clientSecretFile);
}

public VersionOld getCurrentConfigVersion(String project, String subDir) throws Exception {
VersionOld version = commonClient.authorizedRequestBuilder(commonClient.webTarget
.path("/apps/get_current_version/default/"+appName+"/"+appName)
.queryParam("object_type", "app"))
.accept(MediaType.APPLICATION_JSON_TYPE)
.get(ClientResponse.class)
.readEntity(VersionOld.class);

return null;
}
}


and

which gives me that exception:

javax.ws.rs.client.ResponseProcessingException: com.fasterxml.jackson.databind.JsonMappingException: Can not find a deserializer for non-concrete Map type [map type; class javax.ws.rs.core.MultivaluedMap, [simple type, class java.lang.String] -> [collection type; class java.util.List, contains [simple type, class java.lang.Object]]]

at org.glassfish.jersey.client.JerseyInvocation.translate(JerseyInvocation.java:806)
at org.glassfish.jersey.client.JerseyInvocation.access$700(JerseyInvocation.java:92)
at org.glassfish.jersey.client.JerseyInvocation$2.call(JerseyInvocation.java:700)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:444)
at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:696)
at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:420)
at org.glassfish.jersey.client.JerseyInvocation$Builder.get(JerseyInvocation.java:316)


but this code works:

import javax.ws.rs.core.GenericType;
import javax.ws.rs.core.MediaType;
import java.io.InputStream;

import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
import java.util.Map;
/**
* Created by eladb on 9/6/16.
*/
public class DeploymentClient {

private CommonClient commonClient;


String appName = "topic-test-publisher";


public DeploymentClient(String url, InputStream clientSecretFile) {
commonClient = new CommonClient(url, clientSecretFile);
}

public VersionOld getCurrentConfigVersion(String project, String subDir) throws Exception {
String str = commonClient.authorizedRequestBuilder(commonClient.webTarget
.path("/apps/get_current_version/default/"+appName+"/"+appName)
.queryParam("object_type", "app"))
.accept(MediaType.APPLICATION_JSON_TYPE)
.get()
.readEntity(String.class);



VersionOld v = foo(str);
return null;
}

public VersionOld foo(String str){
ObjectMapper objectMapper = new ObjectMapper();
VersionOld v = null;
try {
v = objectMapper.readValue(str, VersionOld.class);
} catch (Exception e) {
e.printStackTrace();
}
return v;
}
}


in both cases the http response is:

str = {"versions": {"ap": "Not Set", "am": "topic-test-publisher-1.0.16", "il": "topic-test-publisher-1.0.16", "row": "topic-test-publisher-1.0.49"}, "provider": "gce"}


how come this code works ok?

Isn't it the same logic?

Answer

Just replace ClientResponse with javax.ws.rs.core.Response in your client code or don't use any arguments at all.

    VersionOld version = commonClient.authorizedRequestBuilder(commonClient.webTarget
            .path("/apps/get_current_version/default/"+appName+"/"+appName)
            .queryParam("object_type", "app"))
            .accept(MediaType.APPLICATION_JSON_TYPE)
            .get(javax.ws.rs.core.Response.class)//or get().readEntity(VersionOld.class);
            .readEntity(VersionOld.class);

I believe that you used org.glassfish.jersey.client.ClientResponse but the resource returned is probably javax.ws.rs.core.Response (it has happened to me also)

I tested with the following server side code

@GET
@Path("/us")
@Produces(MediaType.APPLICATION_JSON)
public Response getJson() { //javax.ws.rs.core.Response
    VersionOld vo = new VersionOld();
    vo.versions.put("ap", "Not set");
    vo.versions.put("am", "topic-test-publisher-1.0.16");
    vo.versions.put("il", "topic-test-publisher-1.0.16");
    vo.versions.put("row", "topic-test-publisher-1.0.49");
    vo.provider = "gce";


    return Response.status(200).entity(vo).build();
}

and the POJO is defined as

public class VersionOld {

  //public variables but you can use getters/setters
public Map<String,String> versions = new HashMap<>();
public String provider;

public VersionOld(){}
  }  

The output is

Msg: topic-test-publisher-1.0.16
Msg: topic-test-publisher-1.0.49
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