MQ 無法連接問題原因

　　If your java program need to connect MQ Server, and you imported the MQ jar files. It still got a NoClassDefFoundErr. The reseason is you used a wrong host ip and port. May be your java program can not load the MQ.properties file. Please check the properties file path.
　　最近工作上需要利用Java開發連接MQ 做交易，測試期間以應用程式模式連接 MQ, 一切設定都寫在 MQ.properties 當一切電文都測試無誤改以 Web Application (JSP) 呼叫電文 method 時卻會出現 NoClassDefFoundError 如下 :

java.lang.NoClassDefFoundError
at com.ibm.mq.MQSESSIONServer.getMQSESSION(MQSESSIONServer.java:67)
at com.ibm.mq.MQSESSION.getSession(MQSESSION.java:240)
at com.ibm.mq.MQManagedConnectionJ11.(MQManagedConnectionJ11.java:148)
at com.ibm.mq.MQBindingsManagedConnectionFactoryJ11._createManagedConnection(MQBindingsManagedConnectionFactoryJ11.java:136)
at com.ibm.mq.MQBindingsManagedConnectionFactoryJ11.createManagedConnection(MQBindingsManagedConnectionFactoryJ11.java:154)
at com.ibm.mq.StoredManagedConnection.(StoredManagedConnection.java:80)
at com.ibm.mq.MQSimpleConnectionManager.allocateConnection(MQSimpleConnectionManager.java:150)
at com.ibm.mq.MQQueueManager.obtainBaseMQQueueManager(MQQueueManager.java:560)
at com.ibm.mq.MQQueueManager.construct(MQQueueManager.java:509)
at com.ibm.mq.MQQueueManager.(MQQueueManager.java:286)
at com.feib.cbd.unisys.gateway.AgentMQRFH2.nightQuery(AgentMQRFH2.java:254)
at _iccardlost__jsp._jspService(D:\Resin\doc\ics\IcCardLost.jsp:51)
at com.caucho.jsp.JavaPage.service(JavaPage.java:75)
at com.caucho.jsp.Page.subservice(Page.java:485)
at com.caucho.server.http.FilterChainPage.doFilter(FilterChainPage.java:182)
at com.caucho.server.http.Invocation.service(Invocation.java:312)
at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:221)
at com.caucho.server.http.HttpRequest.handleConnection(HttpRequest.java:163)
at com.caucho.server.TcpConnection.run(TcpConnection.java:137)
at java.lang.Thread.run(Thread.java:536)

　　一開始也以為是因為 classpath 沒設， 應有的 MQ jar files classpath 沒指定．上 Google 找解答基本上也是如此或是說 .dll (Windows) 或 .so (Linux , UNIX) 沒有放對．

MQ jar files 放到 Resin AP Server 各種 lib目錄, 有時還會出現 UnsatisfiedLinkError 如下 :

java.lang.UnsatisfiedLinkError: no mqjbnd02 in java.library.pathat java.lang.ClassLoader.loadLibrary(ClassLoader.java:1403)at java.lang.Runtime.loadLibrary0(Runtime.java:788)at java.lang.System.loadLibrary(System.java:832)at com.ibm.mq.server.MQSESSION.(MQSESSION.java:139)at com.ibm.mq.MQSESSIONServer.getMQSESSION(MQSESSIONServer.java:67)at com.ibm.mq.MQSESSION.getSession(MQSESSION.java:240)at com.ibm.mq.MQManagedConnectionJ11.(MQManagedConnectionJ11.java:148)at com.ibm.mq.MQBindingsManagedConnectionFactoryJ11._createManagedConnection(MQBindingsManagedConnectionFactoryJ11.java:136)at com.ibm.mq.MQBindingsManagedConnectionFactoryJ11.createManagedConnection(MQBindingsManagedConnectionFactoryJ11.java:154)at com.ibm.mq.StoredManagedConnection.(StoredManagedConnection.java:80)at com.ibm.mq.MQSimpleConnectionManager.allocateConnection(MQSimpleConnectionManager.java:150)at com.ibm.mq.MQQueueManager.obtainBaseMQQueueManager(MQQueueManager.java:560)at com.ibm.mq.MQQueueManager.construct(MQQueueManager.java:509)at com.ibm.mq.MQQueueManager.(MQQueueManager.java:286)at com.feib.cbd.unisys.gateway.AgentMQRFH2.nightQuery(AgentMQRFH2.java:219)at _queryaccountstatus__jsp._jspService(D:\Resin\doc\ics\queryAccountStatus.jsp:56)at com.caucho.jsp.JavaPage.service(JavaPage.java:75)at com.caucho.jsp.Page.subservice(Page.java:485)at com.caucho.server.http.FilterChainPage.doFilter(FilterChainPage.java:182)at com.caucho.server.http.Invocation.service(Invocation.java:312)at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:221)at com.caucho.server.http.HttpRequest.handleConnection(HttpRequest.java:163)at com.caucho.server.TcpConnection.run(TcpConnection.java:137)at java.lang.Thread.run(Thread.java:536)

　　最後真正的原因是 MQ.properties 檔讀不到，改用 hard code 方式指定 MQ Server ip, port 之後一切就正常，供大家參考 !