JBPM6 Service task to execute java code

问题

I am new in JBPM6. My scenario is like this that i want to execute some java code using JBPM service task.From documentation i am not able to understand how to use domain specific process and Work Item Handler in this type of code. If someone have sample example of it please share.That will be very much helpful.

Thank you in advance.

回答1:

Here is how to add a handler inside a Eclipse maven project. I call it the Awesome handler, but your should pick a more specific name.

1) First create a work item definition file in src/main/resources/WorkItemDefinitions.wid. My icon file is located in src/main/resources.

import org.drools.core.process.core.datatype.impl.type.StringDataType;

[
  [
    "name" : "Awesome",
    "parameters" : [
      "Message1" : new StringDataType(),
       "Message2" : new StringDataType()
     ],
    "displayName" : "Awesome",
    "icon" : "icon-info.gif"
  ]
]

2) Create a Work Item Handler Config file in src/main/resources/META-INF/CustomWorkItemHandlers.conf

[
  "Awesome": new org.jbpm.examples.util.handler.AwesomeHandler()
]

3) Create a drools session config file: src/main/resources/META-INF/drools.session.conf

drools.workItemHandlers = CustomWorkItemHandlers.conf

4) Create your Handler so that it matches the class you defined in step 2

public class AwesomeHandler implements WorkItemHandler {

    public AwesomeHandler() {
        super();
    }

    public void executeWorkItem(WorkItem workItem, WorkItemManager manager) {
        System.out.println("Executing Awesome handler");
        manager.completeWorkItem(workItem.getId(), null);
    }

    public void abortWorkItem(WorkItem workItem, WorkItemManager manager) {
        System.out.println("Aborting");
    }
}

5) After you establish the handler, you must register it with your session.

//Get session
KieSession ksession = runtime.getKieSession();

//Register handlers
ksession.getWorkItemManager().registerWorkItemHandler("Awesome", new AwesomeHandler());

At this point you should restart eclipse. When eclipse opens, there should be a 'Custom Tasks' tab in the palette. It should contain an entry labeled 'Awesome' with the specified icon.

回答2:

I know the question is already answered, but I wanted to do the same (execute java code in service task) without creating work item definition (I did't want to use a custom task but a service task as it is). This is how I solved it:

here I read about the ServiceTaskHandler but I couldn't find very good info about the usage.

I read the ServiceTaskHandler code, it uses reflection to run your java code.

I found this (it says jbpm5-samples but I tested with jbpm 6.3), it uses a service task, the service task executes method "hello" from a Class (HelloService) you create:

package com.test;

import java.util.HashMap;
import java.util.Map;

public class HelloService {

    public DataOutput hello(com.test.DataInput name) {
        Map<String, Object> dataMap = new HashMap<String, Object>();
        dataMap.put("s", "Hello " + name.getDataMap().get("s") + "!");
        DataOutput output = new DataOutput(dataMap);
        return output;
    }

}

The ServiceTaskHandler is registered the same way as the step (5) in the answer marked correct:

//Get session
KieSession ksession = runtime.getKieSession();

//Register handlers
ksession.getWorkItemManager().registerWorkItemHandler("Service Task",        new ServiceTaskHandler());

After that I associated the service task with the java class (HelloService - method hello). To do that I used the eclipse bpmn modeler but I didn't find it very intuitive, so I opened the sample's bpmn file (BPMN2-ServiceProcess.bpmn2) with the modeler and filled my service task with the same stuff I read there.

回答3:

Apart from the (excellent) example provided by Mike, if your only goal is to execute some Java code, you can consider using a Script task instead (and just embed the Java code in your process) or reuse the already existing Service Task that can invoke an operation on a Java class.

来源：https://stackoverflow.com/questions/28825365/jbpm6-service-task-to-execute-java-code