Look at the import statements. It shouldn’t be org.json.simple.JSONObject, but
org.json.JSONObject. It’s a different library. If you’re using Maven, get it
using
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20160212</version>
</dependency>
From: Daniela S [mailto:daniela_4...@gmx.at]
Sent: dinsdag 24 mei 2016 22:47
To: user@storm.apache.org
Subject: Aw: Re: RE: Re: Re: Split Kafka JSON String
Thank you for your help!
But unfortunately it still does not work. My code looks as follows:
import org.json.simple.JSONObject;
import backtype.storm.topology.BasicOutputCollector;
import backtype.storm.tuple.Tuple;
public class TestBolt {
public void execute(Tuple input){
String tupleString = input.getString(0);
JSONObject obj = new JSONObject(tupleString);
String command = obj.getString("command");
}
}
But unfortunately I get two errors:
JSONObject obj = new JSONObject(tupleString); --> "the constructor
JSONObject(String) is undefined - remove argument"
String command = obj.getString("command"); --> "change to JSONString"
Do you have any idea why I receive these errors?
Thank you in advance.
Regards,
Daniela
Gesendet: Dienstag, 24. Mai 2016 um 12:00 Uhr
Von: "Ganesh Chandrasekaran"
<gchandraseka...@wayfair.com<mailto:gchandraseka...@wayfair.com>>
An: "user@storm.apache.org<mailto:user@storm.apache.org>"
<user@storm.apache.org<mailto:user@storm.apache.org>>
Betreff: Re: Aw: RE: Re: Re: Split Kafka JSON String
You have to access the 0th index for the string… and then perform the
operations to get the values
public void execute(Tuple tuple) {
String tupleString = tuple.getString(0);
…..
}
From: Daniela S <daniela_4...@gmx.at<mailto:daniela_4...@gmx.at>>
Reply-To: "user@storm.apache.org<mailto:user@storm.apache.org>"
<user@storm.apache.org<mailto:user@storm.apache.org>>
Date: Tuesday, May 24, 2016 at 2:10 PM
To: "user@storm.apache.org<mailto:user@storm.apache.org>"
<user@storm.apache.org<mailto:user@storm.apache.org>>
Subject: Aw: RE: Re: Re: Split Kafka JSON String
Thank you, I tried it, but it is not working. I have to use the Tuple input,
which is a string, containing a JSON, coming from Kafka. When I try the
following:
JSONObject obj = new JSONObject(input); it tells me to remove the argument.
I am also a little bit confused about how to work with the tuples. Do I have to
create an extra bolt for this to extract all the fields from the JSON strings?
What do I do with the extracted fields to use it in my filter bolt and to store
it in Redis? Do I have to use a hash map or something like this?
Thank you in advance.
Regards,
Daniela
Gesendet: Dienstag, 24. Mai 2016 um 19:05 Uhr
Von: "Sinnema, Remon" <remon.sinn...@emc.com<mailto:remon.sinn...@emc.com>>
An: "user@storm.apache.org<mailto:user@storm.apache.org>"
<user@storm.apache.org<mailto:user@storm.apache.org>>
Betreff: RE: Re: Re: Split Kafka JSON String
Import org.json.JSONObject;
JSONObject obj = new JSONObject(jsonString);
String command = obj.getString(“command”);
From: Daniela S [mailto:daniela_4...@gmx.at]
Sent: dinsdag 24 mei 2016 18:08
To: user@storm.apache.org<mailto:user@storm.apache.org>
Subject: Aw: Re: Re: Split Kafka JSON String
Hi,
unfortunately it does not work. Do I need this step? Or is it also possible to
extract the value of a specific field out of my JSON string?
So my JSON string is for example
{"timestamp": "23462626", "ID1": "1", "ID2": "100", "command": "START"}
I would like to use a filter bolt to filter for START and END. So I have to
access the command field within the JSON string.
Afterwards I would like to store the START JSONs in Redis. The key should be
ID1 and ID2. Is that possible? What would be the best way to store it in Redis
and to define two keys for each value?
The END JSONs should be deleted from Redis.
Thank you in advance.
Regards,
Daniela
Gesendet: Montag, 16. Mai 2016 um 14:08 Uhr
Von: "Henry Hottelet" <hotte...@gmail.com<mailto:hotte...@gmail.com>>
An: user@storm.apache.org<mailto:user@storm.apache.org>
Betreff: Re: Re: Split Kafka JSON String
https://code.google.com/archive/p/json-simple/
import org.json.simple.JSONObject;
void main() {
String yourString;
String key;
JSONObject j = yourString;
Redis.put(key,j);
}
—
Henry Hottelet
646-543-6104 (Google Voice: cell/sms)
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On May 16, 2016, at 4:11 AM, Daniela S
<daniela_4...@gmx.at<mailto:daniela_4...@gmx.at>> wrote:
Henry,
thank you for your help. I did not use any github link for my project. I tried
to build the project on my own, with the help of some books and available code
parts from the Internet. I try to explain what I am doing:
1. I have generated random JSON data with a JSON data generator from the
Internet
the JSON data looks as follows:
{"timestamp": "nowTimestamp()",
"ID1": "integer(1,1000)",
"ID2": "integer(1,100)",
"command": "random('START','END')"
}
The JSON generator simulates a data stream, sending the data to a specific
Kafka topic as String
2. I would like to have a KafkaSpout to fetch the data from the Kafka topic.
3. Then I would like to store all the events containing "START" into Redis and
to delete all the events containing "END" from Redis. The key should be a
combination of ID1 and ID2.
4. In the next step I would like to pull all the entries stored in Redis and to
add a specific value for every entry (this values is located in a database and
I have to look it up for every entry). Then I would like to use these values to
build a sum over all entries. This should be repeated every minute, as there
might have been new start or end events. I thought I could use a sliding window
for that.
But unfortunately I have no idea how to proceed with the JSON String, I receive
from Kafka. I already read a lot about the possibility to store JSON Strings in
Redis, but I have no idea how to build the key with both IDs and how to access
the fields in the JSON String.
Hope you can help me.
Thank you so much in advance!
Regards,
Daniela
Gesendet: Sonntag, 15. Mai 2016 um 22:07 Uhr
Von: "Henry Hottelet" <hotte...@gmail.com<mailto:hotte...@gmail.com>>
An: user@storm.apache.org<mailto:user@storm.apache.org>
Betreff: Re: Aw: Re: Split Kafka JSON String
Daniella,
I am curious about your architecture with Kafka and storm. Can you send the
github link you used for that project?
I would like to be able to see your example. I use IntelliJ.
Henry
Sent from my iPad
On May 15, 2016, at 2:14 PM, Daniela S
<daniela_4...@gmx.at<mailto:daniela_4...@gmx.at>> wrote:
Hi,
thank you very much for your answers. But unfortunately I do not have a JSON
object yet, I only have a String, containing a JSON object. I receive the
Strings from Kafka but I do not know how to get the information out of the
String.
example: {"timestamp": 1463335828342, "ID":570,"command":"START"}
I would like to extract the three fields out of the String. Then I would like
to store it into Redis.
Afterwards I would like to pull all the stored (active) devices out of Redis
and to build a sum over all the devices every minute. For building the sum I
have to add another value for every device. I would like to use Redis as a kind
of cache.
Regards,
Daniela
Gesendet: Sonntag, 15. Mai 2016 um 20:06 Uhr
Von: "Henry Hottelet" <hotte...@gmail.com<mailto:hotte...@gmail.com>>
An: user@storm.apache.org<mailto:user@storm.apache.org>
Betreff: Re: Split Kafka JSON String
Try using intellij plug in that converts json to pojo classes
On May 15, 2016 2:04 PM, "Nathan Leung"
<ncle...@gmail.com<mailto:ncle...@gmail.com>> wrote:
Easiest way is to map your job to a pojo and use Jackson or gson to convert the
json.
On May 15, 2016 1:48 PM, "Daniela S"
<daniela_4...@gmx.at<mailto:daniela_4...@gmx.at>> wrote:
Hi
I am receiving Strings of JSON from Kafka. I would like to split the string to
get each field from the JSON object to store it into Redis.
How can I split the string and assign the parts to variables?
Thank you in advance.
Regards,
Daniela
