Mapping JSON data to Java POJO Class with Jackson Mapper

Mapping JSON data to Java POJO Class with Jackson Mapper

I am developing an android application and I am trying to implement the
processing of some Java data using the Stream capabilities of Jackson. To
do this I have a few code example to run through and will explain what
each does as I go.
Here is the JSON I am working with:
{
"users": [
{
"ID": "26",
"data1": "Momonth",
"data2": "2011-10-30 04:34:53"
},
{
"ID": "45",
"data1": "Porto",
"data2": "2011-10-18 05:34:00"
},
{
"ID": "21",
"data1": "Tomson",
"data2": "2011-10-12 02:44:13"
}
],
"success": 1,
}
The code below is the POJO where this data will be stored as it iterates
through each of the "users" array list items in my data:
@JsonRootName(value = "users")
public class User {
String ID;
String data1;
String data2;
...
public String getID() {
return ID;
}
public void setID(String iD) {
ID = iD;
}
public String getData1() {
return data1;
}
public void setData1(String data1) {
this.data1 = data1;
}
public String getData2() {
return data2;
}
public void setData2(String data2) {
this.data2 = data2;
}
...
}
Now the code below I would expect to look at the JSON data and then grab
the "users" array list of objects, I then for now wanted to simply print
the name of each user to the LogCat to review that it works and as
explained earlier I am looking to use the "" method as the data is quite
large and I want to avoid memory issues.
HttpRequest request =
HttpRequest.get("http://www.site.com/android/app/getAllUsers.php");
final Reader reader = request.reader();
final ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true);
final JsonFactory factory = mapper.getFactory();
try {
JsonParser jp = factory.createParser(reader);
while(jp.nextToken() == JsonToken.START_OBJECT) {
String fieldName = jp.getCurrentName();
jp.nextToken();
final User a = mapper.readValue(jp.getText(), User.class);
}
} catch (JsonParseException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
However the code above doesn't work in its current state and I get the
following errors from Jackson:
09-06 11:11:25.326: W/System.err(15029):
com.fasterxml.jackson.databind.JsonMappingException: Current token not
START_OBJECT (needed to unwrap root name 'users'), but FIELD_NAME
09-06 11:11:25.326: W/System.err(15029): at [Source:
java.io.InputStreamReader@432b1580; line: 1, column: 2]
09-06 11:11:25.326: W/System.err(15029): at
com.fasterxml.jackson.databind.ObjectMapper._unwrapAndDeserialize(ObjectMapper.java:2948)
09-06 11:11:25.326: W/System.err(15029): at
com.fasterxml.jackson.databind.ObjectMapper._readValue(ObjectMapper.java:2858)
09-06 11:11:25.326: W/System.err(15029): at
com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:1569)
09-06 11:11:25.326: W/System.err(15029): at
com.app.tool.UsersListActivity$LoadAllUsers.doInBackground(UsersListActivity.java:381)
09-06 11:11:25.326: W/System.err(15029): at
com.app.tool.UsersListActivity$LoadAllUsers.doInBackground(UsersListActivity.java:1)
09-06 11:11:25.326: W/System.err(15029): at
android.os.AsyncTask$2.call(AsyncTask.java:287)
09-06 11:11:25.326: W/System.err(15029): at
java.util.concurrent.FutureTask.run(FutureTask.java:234)
09-06 11:11:25.326: W/System.err(15029): at
android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
09-06 11:11:25.326: W/System.err(15029): at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
09-06 11:11:25.326: W/System.err(15029): at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
09-06 11:11:25.326: W/System.err(15029): at
java.lang.Thread.run(Thread.java:856)
I would really appreciate any help that can be given on this as I am stuck
and cant go forward.
Thanks in advance