我在 WebSphere Application Server 8.5 for RHEL6 (x64) 上部署了两个 Web 应用程序。两个 Web 应用程序都使用 SAPJCO 库连接到部署在 SAP ECC6 中的 BAPI。两个应用程序都需要访问相同的 BAPI 才能创建采购请求。因此，我们使用从 SAP 的 CustomDestinationDataProvider 修改的相同代码进行连接。为了确保应用程序只注册一次，我们使用 Spring 使其成为单例。
然而，当应用程序启动时，一个应用程序（我们猜测它是在第一个应用程序之后加载的）在执行"java.lang.IllegalStateException: DestinationDataProvider already registered"时遇到"com.sap.conn.jco.ext.Environment.registerDestinationDataProvider(myProvider)"。
CustomDestinationDataProvider 如下：
public class CustomDestinationDataProvider { public CustomDestinationDataProvider () { }public static BapiConfigBean bapiConfigBean; //The custom destination data provider implements DestinationDataProvider and //provides an implementation for at least getDestinationProperties(String). //Whenever possible the implementation should support events and notify the JCo runtime //if a destination is being created, changed, or deleted. Otherwise JCo runtime //will check regularly if a cached destination configuration is still valid which incurs //a performance penalty. public static class MyDestinationDataProvider implements DestinationDataProvider { private DestinationDataEventListener eL; private HashMap<String, Properties> secureDBStorage = new HashMap<String, Properties>(); public MyDestinationDataProvider () { } public Properties getDestinationProperties(String destinationName) { try { //read the destination from DB Properties p = secureDBStorage.get(destinationName); if(p!=null) { //check if all is correct, for example if(p.isEmpty()) throw new DataProviderException(DataProviderException.Reason.INVALID_CONFIGURATION, "destination configuration is incorrect", null); return p; } return null; } catch(RuntimeException re) { throw new DataProviderException(DataProviderException.Reason.INTERNAL_ERROR, re); } } //An implementation supporting events has to retain the eventListener instance provided //by the JCo runtime. This listener instance shall be used to notify the JCo runtime //about all changes in destination configurations. public void setDestinationDataEventListener(DestinationDataEventListener eventListener) { this.eL = eventListener; } public boolean supportsEvents() { return true; } //implementation that saves the properties in a very secure way void changeProperties(String destName, Properties properties) { synchronized(secureDBStorage) { if(properties==null) { if(secureDBStorage.remove(destName)!=null) eL.deleted(destName); } else { secureDBStorage.put(destName, properties); eL.updated(destName); // create or updated } } } public void removeDestination(String destName) { // TODO Auto-generated method stub } public void addDestination(String destName, MyDestinationDataProvider myProvider) { // TODO Auto-generated method stub } } // end of MyDestinationDataProvider //business logic void executeCalls(String destName) { JCoDestination dest; try { dest = JCoDestinationManager.getDestination(destName); dest.ping(); System.out.println("Destination " + destName + " works"); } catch(JCoException e) { e.printStackTrace(); System.out.println("Execution on destination " + destName+ " failed"); } } static Properties getDestinationPropertiesFromUI() { //adapt parameters in order to configure a valid destination Properties connectProperties = new Properties(); connectProperties.setProperty(DestinationDataProvider.JCO_ASHOST, getBapiConfigBean().getServerIp()); connectProperties.setProperty(DestinationDataProvider.JCO_SYSNR, getBapiConfigBean().getSystemNumber()); connectProperties.setProperty(DestinationDataProvider.JCO_CLIENT, getBapiConfigBean().getClientId()); connectProperties.setProperty(DestinationDataProvider.JCO_USER, getBapiConfigBean().getUserName()); connectProperties.setProperty(DestinationDataProvider.JCO_PASSWD, getBapiConfigBean().getUserPassword()); connectProperties.setProperty(DestinationDataProvider.JCO_LANG, getBapiConfigBean().getClientLang()); return connectProperties; } static MyDestinationDataProvider myProvider = null; //2014-06-30 00:30 public static void initProvider(BapiConfigBean bapiConfigBean) { CustomDestinationDataProvider.destroy(); setBapiConfigBean(bapiConfigBean); myProvider = new MyDestinationDataProvider(); String destName = getBapiConfigBean().getSapDestname(); try { com.sap.conn.jco.ext.Environment.registerDestinationDataProvider(myProvider); CustomDestinationDataProvider test = new CustomDestinationDataProvider(); myProvider.changeProperties(destName, getDestinationPropertiesFromUI()); test.executeCalls(destName); } catch(IllegalStateException providerAlreadyRegisteredException) { try { JCoDestination jcodest = JCoDestinationManager.getDestination(getBapiConfigBean().getSapDestname()); } catch (JCoException exJCo) { //TODO: Add exception handling and send friendly message to ui } } } public static BapiConfigBean getBapiConfigBean() { return bapiConfigBean; } public static void setBapiConfigBean(BapiConfigBean bapiConfigBean) { CustomDestinationDataProvider.bapiConfigBean = bapiConfigBean; } public static void destroy() { try { Environment.unregisterDestinationDataProvider(myProvider); System.out.println("Unregistered connection to SAP"); } catch (IllegalStateException e) { System.out.println("Failed to unregister connection to SAP: "+ e); } } } </code></pre>
And the error from SystemOut.log in WebSphere is as follow: [6/30/14 22:29:15:198 ICT] 00000043 webapp E com.ibm.ws.webcontainer.webapp.WebApp notifyServletContextCreated SRVE0283E: Exception caught while initializing context: {0} org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jdoConnector' defined in ServletContext resource [/WEB-INF/applicationContext-BAPI.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.sps.tmps.bean.bapi.JCOConnector]: Constructor threw exception; nested exception is java.lang.Error: java.lang.IllegalStateException: DestinationDataProvider already registered [com.sps.tmps.bean.bapi.CustomDestinationDataProvider$MyDestinationDataProvider] Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.sps.tmps.bean.bapi.JCOConnector]: Constructor threw exception; nested exception is java.lang.Error: java.lang.IllegalStateException: DestinationDataProvider already registered [com.sps.tmps.bean.bapi.CustomDestinationDataProvider$MyDestinationDataProvider] Caused by: java.lang.Error: java.lang.IllegalStateException: DestinationDataProvider already registered [com.sps.tmps.bean.bapi.CustomDestinationDataProvider$MyDestinationDataProvider] at com.sps.tmps.bean.bapi.CustomDestinationDataProvider.initProvider(CustomDestinationDataProvider.java:174) at com.sps.tmps.bean.bapi.JCOConnector.(JCOConnector.java:41) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:56) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:39) at java.lang.reflect.Constructor.newInstance(Constructor.java:527) at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:85) at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87) at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:186) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:800) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:720) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:387) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:251) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:156) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:248) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:160) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:287) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:352) at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:244) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:187) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:49) at com.ibm.ws.webcontainer.webapp.WebApp.notifyServletContextCreated(WebApp.java:1678) at com.ibm.ws.webcontainer.webapp.WebAppImpl.initialize(WebAppImpl.java:414) at com.ibm.ws.webcontainer.webapp.WebGroupImpl.addWebApplication(WebGroupImpl.java:88) at com.ibm.ws.webcontainer.VirtualHostImpl.addWebApplication(VirtualHostImpl.java:169) at com.ibm.ws.webcontainer.WSWebContainer.addWebApp(WSWebContainer.java:749) at com.ibm.ws.webcontainer.WSWebContainer.addWebApplication(WSWebContainer.java:634) at com.ibm.ws.webcontainer.component.WebContainerImpl.install(WebContainerImpl.java:426) at com.ibm.ws.webcontainer.component.WebContainerImpl.start(WebContainerImpl.java:718) at com.ibm.ws.runtime.component.ApplicationMgrImpl.start(ApplicationMgrImpl.java:1175) at com.ibm.ws.runtime.component.DeployedApplicationImpl.fireDeployedObjectStart(DeployedApplicationImpl.java:1370) at com.ibm.ws.runtime.component.DeployedModuleImpl.start(DeployedModuleImpl.java:639) at com.ibm.ws.runtime.component.DeployedApplicationImpl.start(DeployedApplicationImpl.java:968) at com.ibm.ws.runtime.component.ApplicationMgrImpl.startApplication(ApplicationMgrImpl.java:774) at com.ibm.ws.runtime.component.ApplicationMgrImpl.start(ApplicationMgrImpl.java:2182) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl.start(CompositionUnitMgrImpl.java:445) at com.ibm.ws.runtime.component.CompositionUnitImpl.start(CompositionUnitImpl.java:123) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl.start(CompositionUnitMgrImpl.java:388) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl.access$500(CompositionUnitMgrImpl.java:116) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl$CUInitializer.run(CompositionUnitMgrImpl.java:994) at com.ibm.wsspi.runtime.component.WsComponentImpl$_AsynchInitializer.run(WsComponentImpl.java:502) at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1862) Caused by: java.lang.IllegalStateException: DestinationDataProvider already registered [com.sps.tmps.bean.bapi.CustomDestinationDataProvider$MyDestinationDataProvider] at com.sap.conn.jco.rt.RuntimeEnvironment.setDestinationDataProvider(RuntimeEnvironment.java:134) at com.sap.conn.jco.ext.Environment.registerDestinationDataProvider(Environment.java:259) at com.sps.tmps.bean.bapi.CustomDestinationDataProvider.initProvider(CustomDestinationDataProvider.java:156) ... 41 more
我的问题是：
1）如何使两个应用程序能够使用相同的 CustomDestinationDataProvider？
2) 如果 2 个应用程序不能使用相同的提供程序，我如何使用相同的服务器/用户/客户端编号访问相同的 BAPI？
这种情况下的限制是（1）我们应该使用 sapjco 和（2）我们只有 BAPI 函数。如果您认为它有问题，可以丢弃 customDestinationDataProvider。顺便说一句，我为长代码和糟糕的格式道歉。
谢谢你。