我从IBM MQ收到一条消息。如何按条件从队列中删除消息？
我试图设置gmo.options = CMQC.MQGMO_MSG_UNDER_CURSOR;但这并没有帮助我。
MQQueue queue = queueManager.accessQueue(e.getIbmQueue().trim(), CMQC.MQOO_INPUT_SHARED | CMQC.MQOO_FAIL_IF_QUIESCING | CMQC.MQOO_INQUIRE, null, null, null);
MQGetMessageOptions gmo = new MQGetMessageOptions();
gmo.options = MQGMO_ALL_MSGS_AVAILABLE | MQGMO_WAIT | MQGMO_PROPERTIES_AS_Q_DEF | MQGMO_FAIL_IF_QUIESCING | MQOO_INPUT_AS_Q_DEF | MQGMO_SYNCPOINT;
gmo.matchOptions = MQMO_MATCH_CORREL_ID;
gmo.waitInterval = 50000;
byte[] body = null;
while (true) {
try {
queue.get(msg, gmo);
body = new byte[msg.getMessageLength()];
String businessIdFromIbm = msg.getStringProperty("usr.uuid");
if (businessIdFromIbm.equals("123")) {
//delete message
}
msg.clearMessage();
}
答案 0 :(得分：0)
以上示例中的queue.get调用是破坏性的get-在该调用期间，该消息将从逻辑上从队列中删除。
您正在使用同步点，因此您需要调用queuemanager.commit（）来完成工作单元（或者，如果您调用queuemanager.disconnect（），则同步点将自动提交）。
MQGMO_MSG_UNDER_CURSOR仅在您打开浏览队列（CMQC.MQOO_BROWSE）并针对该队列发出至少一次浏览时才有效，以便您的应用程序在其浏览光标下有一条有效消息。
如果要浏览消息，然后使用第二个队列将其删除。get将消息删除在浏览光标下，则第一个队列将需要在gmo.options上指定MQGMO_BROWSE_FIRST或MQGMO_BROWSE_NEXT；然后第二个queue.get将需要提供MQGMO_MSG_UNDER_CURSOR作为匹配选项而没有浏览选项集，以破坏性地删除浏览的消息。
MQQueue queue = queueManager.accessQueue(e.getIbmQueue().trim(), CMQC.MQOO_INPUT_SHARED | CMQC.MQOO_BROWSE | CMQC.MQOO_FAIL_IF_QUIESCING | CMQC.MQOO_INQUIRE, null, null, null);
MQGetMessageOptions gmo = new MQGetMessageOptions();
gmo.options = CMQC.MQGMO_ALL_MSGS_AVAILABLE | CMQC.MQGMO_WAIT | CMQC.MQGMO_PROPERTIES_AS_Q_DEF | CMQC.MQGMO_FAIL_IF_QUIESCING | CMQC.MQGMO_BROWSE_NEXT;
gmo.matchOptions = MQMO_MATCH_CORREL_ID;
gmo.waitInterval = 50000;
byte[] body = null;
while (true) {
try {
queue.get(msg, gmo);
body = new byte[msg.getMessageLength()];
String businessIdFromIbm = msg.getStringProperty("usr.uuid");
if (businessIdFromIbm.equals("123")) {
//delete message
MQGetMessageOptions gmo2 = new MQGetMessageOptions();
gmo2.options = CMQC.MQGMO_MSG_UNDER_CURSOR | CMQC.MQGMO_FAIL_IF_QUIESCING | CMQC.MQGMO_SYNCPOINT;
queue.get(msg, gmo2);
// Be prepared to handle the case where the message has been removed by another application (or expired) and so you receive MQRC 2033
queueManager.commit();
}
msg.clearMessage();
}
另一种方法（如果出现问题，则需要较少的队列管理器调用）是使用JMS API到MQ，并在usr.uuid上使用选择器，这样，只有具有将此设置为123将返回到应用程序。参见https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_9.1.0/com.ibm.mq.dev.doc/q031980_.htm
答案 1 :(得分：0)
您可以阅读我的完整博客文章here。这是读者的摘要版本。
对于基于MQ / JMS消息的过滤存在误解。有人认为IBM MQ队列管理器对JMS应用程序做了一些特殊的事情，而对于普通Java或C / C ++ / C＃/ COBOL应用程序则没有。这不是真的。请从知识中心阅读Message selectors in JMS的第一段，以获取更多信息。注意：对于C / C ++ / C＃/ COBOL应用程序，他们可以使用MQOD结构中的SelectionString执行消息选择。
我为POJO MQ应用程序创建了一个消息选择器类。
这里是MQTest12MS的一个片段，向您展示了如何使用MessageSelector类。
ms = new MessageSelector(qMgr);
ms.openQueue(inputQName);
ms.setFilter("SomeNum", MessageSelector.Conditions.GREATER_THAN_EQUAL, 123);
while (true)
{
receiveMsg = ms.getMessage(startAtBeginning);
// got the message, now go and do something with it.
// set flag to continue rather than restart at the beginning.
startAtBeginning = false;
}
ms.closeQueue();
这是MessageSelector类。
import java.io.IOException;
import com.ibm.mq.MQException;
import com.ibm.mq.MQGetMessageOptions;
import com.ibm.mq.MQMessage;
import com.ibm.mq.MQQueue;
import com.ibm.mq.MQQueueManager;
import com.ibm.mq.constants.CMQC;
/**
* Class Name
* MessageSelector
*
* Description
* This java class will retrieve messages from a queue based on a filter.
*
* @author Roger Lacroix
* @version 1.0.0
* @license Apache 2 License
*/
public class MessageSelector
{
public enum Conditions
{
EQUAL, NOT_EQUAL, LESS_THAN, LESS_THAN_EQUAL, GREATER_THAN, GREATER_THAN_EQUAL;
}
private MQQueueManager qMgr = null;
private MQQueue inQ = null;
private String filterName = null;
private Conditions filterCondition;
private Object filterValue = null;
/**
* The constructor
* @param qMgr - must have a valid/active connection to the queue manager
*/
public MessageSelector(MQQueueManager qMgr)
{
super();
this.qMgr = qMgr;
}
/**
* Open the queue for both browsing and destructive gets.
* @param qName
* @throws MQException
*/
public void openQueue(String qName) throws MQException
{
inQ = qMgr.accessQueue(qName, CMQC.MQOO_INQUIRE + CMQC.MQOO_BROWSE + CMQC.MQOO_FAIL_IF_QUIESCING + CMQC.MQOO_INPUT_SHARED);
}
/**
* Close the queue.
* @throws MQException
*/
public void closeQueue() throws MQException
{
if (inQ != null)
inQ.close();
}
/**
* Set the filter name, condition and value.
* @param name
* @param condition
* @param value
* @throws IllegalArgumentException
*/
public void setFilter(String name, Conditions condition, Object value) throws IllegalArgumentException
{
if (name == null)
throw new IllegalArgumentException("Filter name cannot be null.");
else if ("".equals(name))
throw new IllegalArgumentException("Filter name cannot be blank.");
else if (value == null)
throw new IllegalArgumentException("Filter value cannot be null.");
if ( (value instanceof String) || (value instanceof Boolean) ||
(value instanceof Byte) || (value instanceof Byte[]) )
{
if ( (Conditions.EQUAL != condition) && (Conditions.NOT_EQUAL != condition) )
{
throw new IllegalArgumentException("Filter condition can only be EQUAL or NOT_EQUAL.");
}
}
else if ( (value instanceof Integer) || (value instanceof Long) ||
(value instanceof Double) || (value instanceof Float) )
{
if ( (Conditions.EQUAL != condition) && (Conditions.NOT_EQUAL != condition) &&
(Conditions.LESS_THAN != condition) && (Conditions.LESS_THAN_EQUAL != condition) &&
(Conditions.GREATER_THAN != condition) && (Conditions.GREATER_THAN_EQUAL != condition) )
{
throw new IllegalArgumentException("Filter condition must be one of the following: EQUAL, NOT_EQUAL, LESS_THAN, LESS_THAN_EQUAL, GREATER_THAN, GREATER_THAN_EQUAL.");
}
}
else
{
throw new IllegalArgumentException("Unknown Object type for Filter value.");
}
/**
* Pass the checks, save the values
*/
this.filterName = name;
this.filterCondition = condition;
this.filterValue = value;
}
/**
* Retrieve the next matching message from the queue.
* @param reset - Start over from the beginning of the queue.
* @return
* @throws MQException
* @throws IOException
*/
public MQMessage getMessage(boolean reset) throws MQException, IOException
{
MQGetMessageOptions gmo = new MQGetMessageOptions();
if (reset)
gmo.options = CMQC.MQGMO_BROWSE_FIRST + CMQC.MQGMO_NO_WAIT + CMQC.MQGMO_FAIL_IF_QUIESCING;
else
gmo.options = CMQC.MQGMO_BROWSE_NEXT + CMQC.MQGMO_NO_WAIT + CMQC.MQGMO_FAIL_IF_QUIESCING;
MQMessage getMsg = null;
while (true)
{
getMsg = new MQMessage();
inQ.get(getMsg, gmo);
if (performConditionalTest(getMsg))
{
deleteMessage();
break;
}
gmo.options = CMQC.MQGMO_BROWSE_NEXT + CMQC.MQGMO_NO_WAIT + CMQC.MQGMO_FAIL_IF_QUIESCING;
}
return getMsg;
}
/**
* Handle the conditional testing of the value.
* @param getMsg
* @return true/false
*/
private boolean performConditionalTest(MQMessage getMsg)
{
boolean flag = false;
try
{
if (filterValue instanceof String)
{
String value = getMsg.getStringProperty(filterName);
if (value != null)
{
if ( (Conditions.EQUAL == filterCondition) && (((String)filterValue).equals(value)) )
flag = true;
else if ( (Conditions.NOT_EQUAL == filterCondition) && (!(((String)filterValue).equals(value))) )
flag = true;
}
}
else if (filterValue instanceof Integer)
{
int value = getMsg.getIntProperty(filterName);
if ( (Conditions.EQUAL == filterCondition) && (value == (Integer)filterValue) )
flag = true;
else if ( (Conditions.NOT_EQUAL == filterCondition) && (value != (Integer)filterValue) )
flag = true;
else if ( (Conditions.LESS_THAN == filterCondition) && (value < (Integer)filterValue) )
flag = true;
else if ( (Conditions.LESS_THAN_EQUAL == filterCondition) && (value <= (Integer)filterValue) )
flag = true;
else if ( (Conditions.GREATER_THAN == filterCondition) && (value > (Integer)filterValue) )
flag = true;
else if ( (Conditions.GREATER_THAN_EQUAL == filterCondition) && (value >= (Integer)filterValue) )
flag = true;
}
else if (filterValue instanceof Long)
{
long value = getMsg.getLongProperty(filterName);
if ( (Conditions.EQUAL == filterCondition) && (value == (Long)filterValue) )
flag = true;
else if ( (Conditions.NOT_EQUAL == filterCondition) && (value != (Long)filterValue) )
flag = true;
else if ( (Conditions.LESS_THAN == filterCondition) && (value < (Long)filterValue) )
flag = true;
else if ( (Conditions.LESS_THAN_EQUAL == filterCondition) && (value <= (Long)filterValue) )
flag = true;
else if ( (Conditions.GREATER_THAN == filterCondition) && (value > (Long)filterValue) )
flag = true;
else if ( (Conditions.GREATER_THAN_EQUAL == filterCondition) && (value >= (Long)filterValue) )
flag = true;
}
else if (filterValue instanceof Double)
{
double value = getMsg.getDoubleProperty(filterName);
if ( (Conditions.EQUAL == filterCondition) && (value == (Double)filterValue) )
flag = true;
else if ( (Conditions.NOT_EQUAL == filterCondition) && (value != (Double)filterValue) )
flag = true;
else if ( (Conditions.LESS_THAN == filterCondition) && (value < (Double)filterValue) )
flag = true;
else if ( (Conditions.LESS_THAN_EQUAL == filterCondition) && (value <= (Double)filterValue) )
flag = true;
else if ( (Conditions.GREATER_THAN == filterCondition) && (value > (Double)filterValue) )
flag = true;
else if ( (Conditions.GREATER_THAN_EQUAL == filterCondition) && (value >= (Double)filterValue) )
flag = true;
}
else if (filterValue instanceof Float)
{
float value = getMsg.getFloatProperty(filterName);
if ( (Conditions.EQUAL == filterCondition) && (value == (Float)filterValue) )
flag = true;
else if ( (Conditions.NOT_EQUAL == filterCondition) && (value != (Float)filterValue) )
flag = true;
else if ( (Conditions.LESS_THAN == filterCondition) && (value < (Float)filterValue) )
flag = true;
else if ( (Conditions.LESS_THAN_EQUAL == filterCondition) && (value <= (Float)filterValue) )
flag = true;
else if ( (Conditions.GREATER_THAN == filterCondition) && (value > (Float)filterValue) )
flag = true;
else if ( (Conditions.GREATER_THAN_EQUAL == filterCondition) && (value >= (Float)filterValue) )
flag = true;
}
else if (filterValue instanceof Boolean)
{
Boolean value = getMsg.getBooleanProperty(filterName);
if ( (value != null) && ((Boolean)filterValue == value) )
flag = true;
}
else if (filterValue instanceof Byte)
{
byte value = getMsg.getByteProperty(filterName);
if ((Byte)filterValue == value)
flag = true;
}
else if (filterValue instanceof Byte[])
{
byte[] value = getMsg.getBytesProperty(filterName);
if ( (value != null) && (java.util.Arrays.equals((byte[])filterValue, value)) )
flag = true;
}
}
catch (Exception e)
{}
return flag;
}
/**
* Delete the message that the cursor is pointing to.
*/
private void deleteMessage()
{
MQMessage deleteMsg = new MQMessage();
MQGetMessageOptions gmo = new MQGetMessageOptions();
gmo.options = CMQC.MQGMO_MSG_UNDER_CURSOR + CMQC.MQGMO_NO_WAIT + CMQC.MQGMO_FAIL_IF_QUIESCING + CMQC.MQGMO_ACCEPT_TRUNCATED_MSG;
/**
* don't need it - because we already have the message
* just delete it.
*/
try
{
inQ.get(deleteMsg, gmo, 1); // only get 1 byte - who cares right!!
}
catch (MQException e)
{}
}
}
更新2019/06/25：我更新了MessageSelector类的setFilter方法。