在客户端对象上调用activate方法时获取空指针异常.这是我的代码.
@RequestMapping(value="/loanreq",method=RequestMethod.GET)
public String loanRequest(HttpServletRequest req,HttpSession session) throws DroolsParserException,IOException,NamingException{
StatefulKNowledgeSession ksession = processEngine.getKsession();
ksession.getWorkItemmanager().registerWorkItemHandler("Human Task",new WSHumanTaskHandler());
TaskClient client = new TaskClient(new MinaTaskClientConnector("UserTask",new MinaTaskClientHandler(SystemEventListenerFactory.getSystemEventListener())));
client.connect("ipaddress",9123);
BlockingTaskOperationResponseHandler responseHandler =
new BlockingTaskOperationResponseHandler();
client.activate(3,"krisv",responseHandler);
client.start(3,responseHandler);
client.complete( 3,null,responseHandler );
Map<String,Object> params=new HashMap();
params.put("employee","krisv");
ProcessInstance processInstance =ksession.startProcess("com.vr.controller2",params);
System.out.println("id is "+processInstance.getId());
return "return1";
}
我得到以下例外
java.lang.NullPointerException at org.jbpm.task.service.mina.MinaTaskClientConnector.write(MinaTaskClientConnector.java:118) at org.jbpm.task.service.TaskClient.activate(TaskClient.java:651) at com.vr.controller.hellocontroller.loanRequest(hellocontroller.java:181) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.springframework.web.method.support.invocableHandlerMethod.invoke(invocableHandlerMethod.java:212) at org.springframework.web.method.support.invocableHandlerMethod.invokeForRequest(invocableHandlerMethod.java:126) at org.springframework.web.servlet.mvc.method.annotation.ServletinvocableHandlerMethod.invokeAndHandle(ServletinvocableHandlerMethod.java:96) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80) at org.springframework.web.servlet.dispatcherServlet.dodispatch(dispatcherServlet.java:900) at org.springframework.web.servlet.dispatcherServlet.doService(dispatcherServlet.java:827) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778) at javax.servlet.http.HttpServlet.service(HttpServlet.java:621) at javax.servlet.http.HttpServlet.service(HttpServlet.java:728) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:311) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:101) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.authentication.logout.logoutFilter.doFilter(logoutFilter.java:105) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323) at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:173) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:745)
我在调试时看到了客户端对象,但它不是null.不知道为什么我收到此错误.我在“client.activate()”行而不是“client.connect()”收到此错误.
解决方法
根据堆栈跟踪,出现此错误,因为MinaTaskClientConnector中的会话为空.据我所知,源代码为
TaskClient和
MinaTaskClientConnector,这是因为connect方法失败,在这段代码中：
try {
connector.getFilterChain().addLast("codec",new ProtocolCodecFilter(new ObjectSerializationCodecFactory()));
ConnectFuture future1 = connector.connect( address );
future1.awaitUninterruptibly();
if (!future1.isConnected()) {
return false;
}
session = future1.getSession();
return true;
} catch (Exception e) {
logger.error(e.getMessage(),e);
return false;
}
您可以在日志中找到确切的错误,也可以在catch块中放置断点.
另外我建议检查connect方法的结果(它返回布尔值以指示连接成功)并执行以下操作：
if (client.connect("ipaddress",9123) {
BlockingTaskOperationResponseHandler responseHandler = new BlockingTaskOperationResponseHandler();
client.activate(3,responseHandler);
client.start(3,responseHandler);
client.complete( 3,responseHandler );
Map<String,Object> params=new HashMap();
params.put("employee","krisv");
ProcessInstance processInstance =ksession.startProcess("com.vr.controller2",params);
System.out.println("id is "+processInstance.getId());
return "return1";
} else {
//Todo code to report connection error
}