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| End of file exception when using MQ classes for Java |
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Message
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| csongebalazs |
 Posted: Thu May 15, 2014 10:58 pm Post subject: End of file exception when using MQ classes for Java |
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Voyager
Joined: 30 Jan 2004
Posts: 78
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Hi,
I am brand new in java, and maybe I asking noob questions, but need help. 
I decided to make a simple java application which can connect to a queue manager, send and receive message from a queue. I started very basic way, and sent a message (from a JTextArea) using writeUTF method of an MQMessage object, and receiving the message with the readUTF method. Everything was fine.
So I decided to try read message which was sent by mqsiput.exe, and which contains MQRFH2 header with usr fields. And found many problems. First I had to realize, readUTF is not a good way to get message text.
Now, if I trying to do the following:
| Code: |
MQHeaderList lista = new MQHeaderList(rcvMessage, false);
int index = lista.indexOf ("MQRFH2");
setConsolText(Integer.toString(index));
byte[] b = new byte[rcvMessage.getMessageLength()];
rcvMessage.readFully(b);
String msgText = new String(b);
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then I got a following log and error:
| Code: |
Getting a message...
0
An IOException occured whilst writing to the message buffer: java.io.EOFException: MQJE086: End of file exception ('MQMessage.readFully()'). |
But when I change order of the code, I can read the whole message (included the MQRFH2 header) into a string, but header list is empty.
| Code: |
byte[] b = new byte[rcvMessage.getMessageLength()];
rcvMessage.readFully(b);
String msgText = new String(b);
MQHeaderList lista = new MQHeaderList(rcvMessage, false);
int index = lista.indexOf ("MQRFH2");
setConsolText(Integer.toString(index)); |
and
| Code: |
Getting a message...
-1
The received message body displayed in message text panel. |
Pls, can someone explain, why is this working this way?
And how can I get header list and get message body text into a string at a same time? |
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| csongebalazs |
| Posted: Fri May 16, 2014 12:00 am Post subject: |
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Voyager
Joined: 30 Jan 2004
Posts: 78
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If I doing the following, i can read header and body  :
| Code: |
MQHeaderIterator hi = new MQHeaderIterator (rcvMessage);
while (hi.hasNext())
{
MQHeader header = hi.nextHeader();
setConsolText("+1");
setConsolText("Header type " + header.type() + ": " + header);
}
String msgText = hi.getBodyAsText();
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But still can someone explain why my previous solution was wrong?  |
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| fjb_saper |
| Posted: Fri May 16, 2014 1:24 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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Glad you managed it. However you should also think about not using the RFH header, if all you need out of it is in its user folder.
Use the gmo/pmo option propertiesInHandle and see the information being now a property of the message... The same way do not set the RFH set the properties on the message. For those who need the RFH, the queue setting of msgprop=compat will deliver the msg either with properties or RFH2 depending on their gmo options....
Have fun 
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MQ & Broker admin |
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| csongebalazs |
| Posted: Fri May 16, 2014 1:53 am Post subject: |
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Voyager
Joined: 30 Jan 2004
Posts: 78
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Not using RFH2 header is not an option for me, I must.
Anyway, still can someone explain, why linked code not worked as way as i expected? |
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| fjb_saper |
| Posted: Fri May 16, 2014 7:29 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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| csongebalazs wrote: |
Not using RFH2 header is not an option for me, I must.
Anyway, still can someone explain, why linked code not worked as way as i expected? |
Not quite... If you use properties in handle and msgprop=Compat the receiver will see an RFH header (if he/she, in turn, does not specify properties in handle)...
As to your question about the message and header, what is wrong with the following picture:
| Code: |
byte[] b = new byte[rcvMessage.getMessageLength()];
rcvMessage.readFully(b);
String msgText = new String(b); |
Remember that at this point the payload contains both headers and data.
And I don't remember seeing that it was ok to treat the header as text...
So you could get an exception at new String(b); ...
Have fun
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| calanais |
| Posted: Fri May 16, 2014 8:06 am Post subject: |
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Apprentice
Joined: 12 Mar 2010
Posts: 32
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Hi;
Just to pick up on a comment above; could you expand on the reasons for using the com.ibm.mq.* ("Base Java Classes") rather than the WMQ JMS provision?
For handling a simple set of text, JMS would be a simpler model.
It is sometimes required to iterate over the headers, especially when connecting to systems/applications that need to manually create headers. For a new application I would move to the JMS route. If there's a specific barrier to entry for JMS would be interested to know.
Matthew |
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| csongebalazs |
| Posted: Fri May 23, 2014 12:26 am Post subject: |
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Voyager
Joined: 30 Jan 2004
Posts: 78
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Thanks for replies and advices what should I do instead of what I done.
As I told I am brand new in Java, and the Using WebSphere MQ classes for Java chapter was before than the Using WebSphere MQ classes for JMS chapter, and I started to read sequentially. JMS can be better and easier way, but that is still a blind area for me.  Of course I will read/watch/learn.
Anyway, luckily my excollege told me how can I make it to work with MQHeaderIterator. 
After reading headers with this iterator, I should use the following code to read message body:
byte[] b = new byte[rcvMessage.getDataLength()];
rcvMessage.readFully(b);
Tested, and it is working!  |
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