我可以在 Script-Task 和 kcontext-instance 的帮助下成功地从进程中检索全局变量（如 NodeInstance、ProcessInstance 等）；但是，如果我需要在 WorkItem 中检索这些全局变量怎么办？我当然可以将 Script-Task 放在 Process 中的 WorkItem 之前，然后将全局变量分配给变量定义之一，以便通过 getParameter()-method 在 WorkItem 中使用它；
但我们确实明白，这是双重工作，不是吗？那么如何在没有额外脚本任务的情况下在 WorkItem 中获取全局变量呢？我首先想到的是，我可以在 WorkItem 中使用相同的会话名称，例如我们通过在 KieWorkBench 中注册 WorkItem 来定义，这就是我在 WI 中创建 ProcessContext 的原因，如下所示：
KieServices ks = KieServices.Factory.get();
KieContainer kContainer = ks.getKieClasspathContainer();
KieSession kSession = kContainer.newKieSession("ksession-process");
ProcessContext context = new ProcessContext(kSession);
Map<String, Object> params = new HashMap<>();
public void executeWorkItem(WorkItem workItem, WorkItemManager manager) {
params.put("lane", context.getNodeInstance().getNode().getMetaData().get("Lane").toString());
manager.completeWorkItem(workItem.getId(), params);
}
使用 executeWorkItem() 中的此代码片段，而不是 Script-Task 中的 kcontext，我可以成功检索车道的名称并将其分配给变量，但是当我使用此 WorkItem 执行流程时，我得到一个错误 - WorkItem -- null不是通过部署，而是通过启动流程；当然，我还注册了与 KieWorkBench 中的 WorkItem（即“ksession-process”）中相同的 ksession - 名称，但显然我不能像我想的那样以这种方式使用上下文。
所以我真的很感谢你的帮助！它并没有真正打扰，而是制作一个代码。BProcess 稍微简洁一点，没有任何多余的变量，问一下是值得的。
jBPM 6.4，野飞 8.2
更新： 正如用户 livthomas 所建议的，我尝试将我的类扩展为 AbstractWorkiItemHandler 而不是 WorkItemHandler 接口，如下所示：
public class WI extends AbstractWorkItemHandler {
public WI(StatefulKnowledgeSession ksession) {
super(ksession);
}
KieSession kSession = getSession();
ProcessContext context = new ProcessContext(kSession);
Map<String, Object> params = new HashMap<>();
public void executeWorkItem(WorkItem workItem, WorkItemManager manager) {
params.put("lane", context.getNodeInstance().getNode().getMetaData().get("Lane"));
manager.completeWorkItem(workItem.getId(), params);
}
...
然后在项目的descriptor.xml中注册为new my_package.WI(ksession); 不幸的是，我得到了 RuntimeException: cannot instance WorkItem...
UPDATE2：堆栈跟踪
2016-09-13 11:49:59,355 ERROR [org.jbpm.console.ng.bd.backend.server.DeploymentManagerEntryPointImpl] (default task-24) Deployment of unit testing:testing-work-item-handler:1.0 failed: java.lang.RuntimeException: java.lang.RuntimeException: Cannot instance WorkItemHandler bpmstest.test.WI: org.jbpm.console.ng.bd.exception.DeploymentException: java.lang.RuntimeException: java.lang.RuntimeException: Cannot instance WorkItemHandler bpmstest.test.WI
at org.jbpm.console.ng.bd.backend.server.DeploymentManagerEntryPointImpl.deploy(DeploymentManagerEntryPointImpl.java:203) [jbpm-console-ng-business-domain-backend-6.4.0.Final.jar:6.4.0.Final]
at org.jbpm.console.ng.bd.backend.server.DeploymentManagerEntryPointImpl.deploy(DeploymentManagerEntryPointImpl.java:158) [jbpm-console-ng-business-domain-backend-6.4.0.Final.jar:6.4.0.Final]
at org.jbpm.console.ng.bd.backend.server.DeploymentManagerEntryPointImpl.process(DeploymentManagerEntryPointImpl.java:517) [jbpm-console-ng-business-domain-backend-6.4.0.Final.jar:6.4.0.Final]
at org.jbpm.console.ng.bd.backend.server.DeploymentManagerEntryPointImpl$Proxy$_$$_WeldClientProxy.process(Unknown Source) [jbpm-console-ng-business-domain-backend-6.4.0.Final.jar:6.4.0.Final]
at org.kie.workbench.common.services.backend.builder.BuildServiceImpl.doBuildAndDeploy(BuildServiceImpl.java:178) [kie-wb-common-services-backend-6.4.0.Final.jar:6.4.0.Final]
at org.kie.workbench.common.services.backend.builder.BuildServiceImpl.buildAndDeploy(BuildServiceImpl.java:134) [kie-wb-common-services-backend-6.4.0.Final.jar:6.4.0.Final]
at org.kie.workbench.common.services.backend.builder.BuildServiceImpl$Proxy$_$$_WeldClientProxy.buildAndDeploy(Unknown Source) [kie-wb-common-services-backend-6.4.0.Final.jar:6.4.0.Final]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.8.0_72]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [rt.jar:1.8.0_72]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.8.0_72]
at java.lang.reflect.Method.invoke(Method.java:498) [rt.jar:1.8.0_72]
at org.jboss.errai.bus.server.io.AbstractRPCMethodCallback.invokeMethodFromMessage(AbstractRPCMethodCallback.java:48) [errai-bus-3.2.3.Final.jar:3.2.3.Final]
at org.jboss.errai.bus.server.io.ValueReplyRPCEndpointCallback.callback(ValueReplyRPCEndpointCallback.java:22) [errai-bus-3.2.3.Final.jar:3.2.3.Final]
at org.jboss.errai.bus.server.io.RemoteServiceCallback.callback(RemoteServiceCallback.java:54) [errai-bus-3.2.3.Final.jar:3.2.3.Final]
at org.jboss.errai.cdi.server.CDIExtensionPoints$2.callback(CDIExtensionPoints.java:410) [errai-weld-integration-3.2.3.Final.jar:3.2.3.Final]
at org.jboss.errai.bus.server.DeliveryPlan.deliver(DeliveryPlan.java:47) [errai-bus-3.2.3.Final.jar:3.2.3.Final]
at org.jboss.errai.bus.server.ServerMessageBusImpl.sendGlobal(ServerMessageBusImpl.java:296) [errai-bus-3.2.3.Final.jar:3.2.3.Final]
at org.jboss.errai.bus.server.SimpleDispatcher.dispatchGlobal(SimpleDispatcher.java:46) [errai-bus-3.2.3.Final.jar:3.2.3.Final]
at org.jboss.errai.bus.server.service.ErraiServiceImpl.store(ErraiServiceImpl.java:97) [errai-bus-3.2.3.Final.jar:3.2.3.Final]
at org.jboss.errai.bus.server.service.ErraiServiceImpl.store(ErraiServiceImpl.java:114) [errai-bus-3.2.3.Final.jar:3.2.3.Final]
at org.jboss.errai.bus.server.servlet.DefaultBlockingServlet.doPost(DefaultBlockingServlet.java:142) [errai-bus-3.2.3.Final.jar:3.2.3.Final]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) [jboss-servlet-api_3.1_spec-1.0.0.Final.jar:1.0.0.Final]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [jboss-servlet-api_3.1_spec-1.0.0.Final.jar:1.0.0.Final]
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:86) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:130) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at org.uberfire.ext.security.server.SecureHeadersFilter.doFilter(SecureHeadersFilter.java:69) [uberfire-servlet-security-0.8.0.Final.jar:0.8.0.Final]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:132) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at org.uberfire.ext.security.server.SecurityIntegrationFilter.doFilter(SecurityIntegrationFilter.java:61) [uberfire-servlet-security-0.8.0.Final.jar:0.8.0.Final]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:60) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:132) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:85) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.server.handlers.DisableCacheHandler.handleRequest(DisableCacheHandler.java:33) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.security.handlers.AuthenticationConstraintHandler.handleRequest(AuthenticationConstraintHandler.java:51) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.security.ServletSecurityConstraintHandler.handleRequest(ServletSecurityConstraintHandler.java:56) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:58) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:70) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.security.handlers.SecurityInitialHandler.handleRequest(SecurityInitialHandler.java:76) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:261) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:248) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:77) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:167) [undertow-servlet-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:199) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:761) [undertow-core-1.1.8.Final.jar:1.1.8.Final]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [rt.jar:1.8.0_72]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [rt.jar:1.8.0_72]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.8.0_72]
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: java.lang.RuntimeException: Cannot instance WorkItemHandler bpmstest.test.WI
at org.jbpm.kie.services.impl.KModuleDeploymentService.deploy(KModuleDeploymentService.java:201) [jbpm-kie-services-6.4.0.Final.jar:6.4.0.Final]
at org.jbpm.services.cdi.impl.DeploymentServiceCDIImpl$Proxy$_$$_WeldClientProxy.deploy(Unknown Source) [jbpm-services-cdi-6.4.0.Final.jar:6.4.0.Final]
at org.jbpm.console.ng.bd.backend.server.DeploymentManagerEntryPointImpl.deploy(DeploymentManagerEntryPointImpl.java:194) [jbpm-console-ng-business-domain-backend-6.4.0.Final.jar:6.4.0.Final]
... 59 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: Cannot instance WorkItemHandler bpmstest.test.WI
at org.jbpm.kie.services.impl.AbstractDeploymentService.commonDeploy(AbstractDeploymentService.java:161) [jbpm-kie-services-6.4.0.Final.jar:6.4.0.Final]
at org.jbpm.kie.services.impl.KModuleDeploymentService.deploy(KModuleDeploymentService.java:196) [jbpm-kie-services-6.4.0.Final.jar:6.4.0.Final]
... 61 more
Caused by: java.lang.RuntimeException: Cannot instance WorkItemHandler bpmstest.test.WI