java websphere MQ

问题:

My aim is to put n number of messages in a for loop to a WebSphere MQ queue using WebSphere MQ java programming.

My java program will run as a standalone program.

If any exception in between , I need to rollback all the messages.

If no exception then I should commit all the messages .

The outside world should not see my messages in the queue until I complete fully. How do I achieve this?

Updated with sample code as per reply from T.Rob:

Please check if sample code is fine ?

Does setting MQGMO_SYNCPOINT is only related to my program's invocation ? (because similar programs running parallely will also be putting messages on the same queue and those messages should not gett affected by my program's SYNCPOINT.)

public void sendMsg() {         MQQueue queue = null;         MQQueueManager queueManager = null;         MQMessage mqMessage = null;         MQPutMessageOptions pmo = null;         System.out.println("Entering..");         try {             MQEnvironment.hostname = "x.x.x.x";             MQEnvironment.channel = "xxx.SVRCONN";             MQEnvironment.port = 9999;               queueManager = new MQQueueManager("XXXQMANAGER");             int openOptions = MQConstants.MQOO_OUTPUT;                   queue = queueManager.accessQueue("XXX_QUEUENAME", openOptions, null, null, null);              pmo = new MQPutMessageOptions();              pmo.options = CMQC.MQGMO_SYNCPOINT;               String input = "testing";             System.out.println("sending messages....");             for (int i = 0; i < 10; i++) {                 input = input + ": " + i;                 mqMessage = new MQMessage();                 mqMessage.writeString(input);                 System.out.println("Putting message: " + i);                 queue.put(mqMessage, pmo);              }             queueManager.commit();             System.out.println("Exiting..");          } catch (Exception e) {             e.printStackTrace();             try {                 System.out.println("rolling back messages");                 if (queueManager != null)                     queueManager.backout();             } catch (MQException e1) {                 e1.printStackTrace();             }         } finally {             try {                 if (queue != null)                     queue.close();                 if (queueManager != null)                     queueManager.close();             } catch (MQException e) {                 e.printStackTrace();             }         }     } 

回答1:

WMQ supports both local and global (XA) units of work. The local units of work are available simply by specifying the option. Global XA transactions require a transaction manager, as mentioned by keithkreissl in another answer.

For what you described, a POJO doing messaging under syncpoint, specify MQC.MQGMO_SYNCPOINT in your MQGetMessageOptions. When you are ready to commit, issue the MQQManager.commit() or MQQManager.backout() call.

Note that the response and doc provided by ggrandes refers to the JMS and not Java classes. The Java classes use Java equivalents of the WMQ procedural API, can support many threads (doc) and even provide connection pooling (doc). Please refer to the Java documentation rather than the JMS documentation for the correct behavior. Also, I've linked to the WMQ V7.5 documentation which goes with the latest WMQ Java V7.5 client. The later clients have a lot more local functionality (tracing, flexible install path, MQClient.ini, etc.) and work with back-level QMgrs. It is highly recommended to be using the latest client and the download is free.

回答2:

you only need to create a session with transaction enabled.

Session session; // ... boolean transacted = true; session = connection.createSession(transacted, Session.AUTO_ACKNOWLEDGE); try {     // ...do things...     session.commit(); } catch (Exception e) {     session.rollback(); } // ... 

WARN-NOTE: Sessions are not thread-safe ;-)

• Doc Websphere MQ/JMS

回答3:

If you have access to a transaction manager and more importantly an XATransaction wired up to your MQ access, you can start a transaction at the beginning of your message processing put all the messages on the queue then commit the transaction. Using the XATransactions it will not put any messages until the transaction commits. If you don't have access to that, you can do a little more plumbing by placing your messages in a local data object, wrap your code in a try/catch if no exceptions iterate through the local data object sending the messages. The issue with the later approach is that it will commit all your other processing but if a problem occurs in the sending of messages your other processing will not be rolled back.

文章来源: java websphere MQ