Kafka consumer - want to print partition id along with message

["kader81@yahoo.com.INVALID" <ka...@yahoo.com.INVALID>]

Hi, 

I am trying to learn more on Kafka consuming patterns if we have partitions on the topic and testing few scenarios. I would like to print the message when the consumer consumes along with the partition id. How to get this done ? 

We have simple consumer code (high level) 

  public void run() { 
        ConsumerIterator<byte[], byte[]> it = m_stream.iterator(); 
        while (it.hasNext()) 
            System.out.println("Thread " + m_threadNumber + ": " + new String(it.next().message())); 
        System.out.println("Shutting down Thread: " + m_threadNumber); 
    } 

How to print the message as well as partition id ? 

Tried to assign it.next() to MessageandMetadata variable and printed partition id (which is declared as int). But while printing message() - it is declared as object in MessageandMetadata. Message is getting printed as junk data 

Tried this: 

MessageandMetadata msg; 
msg = it.next() 
System.out.println("Partition "+ msg.partition() + "Message data" + msg.message().tostring()); 

Here msg.message() is not printing string value.   
Can anyone help on this. 

Kader .

Sent from Yahoo Mail on Android

Re: Kafka consumer - want to print partition id along with message

[Jun Rao <ju...@gmail.com>]

You need to define msg as MessageAndMetadata<byte[], byte[]>.

Thanks,

Jun

On Mon, Nov 17, 2014 at 10:43 PM, kader81@yahoo.com.INVALID <
kader81@yahoo.com.invalid> wrote:

> Hi,
>
> I am trying to learn more on Kafka consuming patterns if we have
> partitions on the topic and testing few scenarios. I would like to print
> the message when the consumer consumes along with the partition id. How to
> get this done ?
>
> We have simple consumer code (high level)
>
>   public void run() {
>         ConsumerIterator<byte[], byte[]> it = m_stream.iterator();
>         while (it.hasNext())
>             System.out.println("Thread " + m_threadNumber + ":
> " + new String(it.next().message()));
>         System.out.println("Shutting down Thread: " + m_threadNumber);
>     }
>
> How to print the message as well as partition id ?
>
> Tried to assign it.next() to MessageandMetadata variable and printed
> partition id (which is declared as int). But while printing message() - it
> is declared as object in MessageandMetadata. Message is getting printed as
> junk data
>
> Tried this:
>
> MessageandMetadata msg;
> msg = it.next()
> System.out.println("Partition "+ msg.partition() + "Message data" +
> msg.message().tostring());
>
> Here msg.message() is not printing string value.
> Can anyone help on this.
>
> Kader .
>
> Sent from Yahoo Mail on Android
>
>