Hi Yuheng,
Don't worry about Storm, just use Gson in standard Java.
String json = ...
// If you don't know the structure of the data, you can do this
JsonArray array = new Gson().fromJson(json, JsonArray.class);
JsonObject object = new Gson().fromJson(json, JsonObject.class);
// What is normally done:
public static class MyObj {
int a;
String b;
}
MyObj deserializedObject = new Gson().fromJson(json, MyObj.class);
If you want to send the MyObj instance from bolt to bolt, then just make
sure it implements Serializable, and you can emit it as part of a tuple.
Steve
On Thu, Nov 6, 2014 at 11:11 AM, Yuheng Du <[email protected]> wrote:
> Hi Stephen,
>
> Can you give a tiny example to explain how can I use gson to do that? I am
> quite new to storm serialization/deserialization.
>
> I need to deserialize a json format string from the spout into jsonobject
> or jsonarray.
>
> Thanks.
>
>
>
> On Thu, Nov 6, 2014 at 1:25 PM, Stephen Armstrong <
> [email protected]> wrote:
>
>> I'm currently doing json serialize/deserialize using gson-2.3 on
>> storm-0.9.2-incubating and it seems to be working fine.
>>
>> On Wed, Nov 5, 2014 at 5:18 PM, Yuheng Du <[email protected]> wrote:
>>
>>> Does anyone implemented a JSON serialization scheme for Strom version >=
>>> 0.9.0?
>>>
>>> On Wed, Nov 5, 2014 at 2:24 PM, Yuheng Du <[email protected]> wrote:
>>>
>>>> Hi guys,
>>>>
>>>> I am using rabbitmq-spout offered by
>>>> https://github.com/ppat/storm-rabbitmq to read data from rabbitmq.
>>>> Here is what I see in the console when I run the topology locally:
>>>>
>>>> 101703 [Thread-16-storm-obser-spout] INFO
>>>> backtype.storm.daemon.executor - Acking message 33
>>>> 113099 [Thread-16-storm-obser-spout] INFO backtype.storm.daemon.task -
>>>> Emitting: storm-obser-spout default
>>>> [{"readings":[0.0,0.0,0.0,88.007,0.0,0.0,0.0,17.83,64.0,0.0,0.0,0.0,0.0,11.071,0.2,1.69,0.0,0.0,-0.23,88.007,0.0,0.0,0.0,0.0,0.0,0.0],"observationId":"f45ef06f-88dc-4d50-b28e-24937dda5240","deploymentId":"
>>>> http://www.xxxx.org/resource/deployment#aiken_8","deviceId":"0","observationDateTime":"11-05-2014
>>>> 19:05:15 UTC"},
>>>> io.latent.storm.rabbitmq.RabbitMQMessageScheme$Envelope@2a8ec790,
>>>> io.latent.storm.rabbitmq.RabbitMQMessageScheme$Properties@3cfd4c4]
>>>> 113099 [Thread-16-storm-obser-spout] INFO backtype.storm.daemon.task -
>>>> Emitting: storm-obser-spout __ack_init [-3424274568001459772 0 2]
>>>>
>>>> Can anybody tell me where does these two lines come from:
>>>> "io.latent.storm.rabbitmq.RabbitMQMessageScheme$Envelope@2a8ec790,
>>>> io.latent.storm.rabbitmq.RabbitMQMessageScheme$Properties@3cfd4c4" ?
>>>>
>>>> How can I parse each field in my JSON format messages like "readings"
>>>> and "observationDateTime"?
>>>>
>>>> I attached my topology source code.
>>>>
>>>> Thanks.
>>>>
>>>>
>>>
>>
>
