Activiti实现流程自由跳转

import org.activiti.engine.ProcessEngine;
import org.activiti.engine.TaskService;
import org.activiti.engine.impl.RepositoryServiceImpl;
import org.activiti.engine.impl.RuntimeServiceImpl;
import org.activiti.engine.impl.interceptor.Command;
import org.activiti.engine.impl.interceptor.CommandContext;
import org.activiti.engine.impl.persistence.entity.ExecutionEntity;
import org.activiti.engine.impl.persistence.entity.ProcessDefinitionEntity;
import org.activiti.engine.impl.persistence.entity.TaskEntity;
import org.activiti.engine.impl.pvm.process.ActivityImpl;

/**
* Created by Administrator on 2016/11/11.
*/
public class TaskFlowControlService {
ProcessEngine _processEngine;
private String _processId;

public TaskFlowControlService(ProcessEngine processEngine, String processId)
{
this._processEngine = processEngine;
this._processId = processId;
}

/**
*  跳转至指定活动节点
* @param targetTaskDefinitionKey
*/
public void jump(String targetTaskDefinitionKey){
TaskEntity currentTask = (TaskEntity)_processEngine.getTaskService()
.createTaskQuery()
.processInstanceId(_processId).singleResult();
jump(currentTask,targetTaskDefinitionKey);
}

/**
* @param currentTaskEntity 当前任务节点
* @param targetTaskDefinitionKey  目标任务节点（在模型定义里面的节点名称）
*/
private void jump(final TaskEntity currentTaskEntity, String targetTaskDefinitionKey){
final ActivityImpl activity = getActivity(_processEngine,
currentTaskEntity.getProcessDefinitionId(),targetTaskDefinitionKey);
final ExecutionEntity execution = (ExecutionEntity)_processEngine.getRuntimeService()
.createExecutionQuery().executionId(currentTaskEntity.getExecutionId()).singleResult();
final TaskService taskService = _processEngine.getTaskService();
((RuntimeServiceImpl)_processEngine.getRuntimeService()).getCommandExecutor()
.execute(new Command<java.lang.Void>() {
public Void execute(CommandContext commandContext) {

//创建新任务
execution.setActivity(activity);
execution.executeActivity(activity);

//删除当前的任务
//不能删除当前正在执行的任务，所以要先清除掉关联
currentTaskEntity.setExecutionId(null);
taskService.saveTask(currentTaskEntity);
taskService.deleteTask(currentTaskEntity.getId(),true);
return null;
}
});
}

private ActivityImpl getActivity(ProcessEngine processEngine, String processDefId, String activityId)
{
ProcessDefinitionEntity pde = getProcessDefinition(processEngine, processDefId);
return pde.findActivity(activityId);
}

private ProcessDefinitionEntity getProcessDefinition(ProcessEngine processEngine, String processDefId)
{
return (ProcessDefinitionEntity) ((RepositoryServiceImpl) processEngine.getRepositoryService())
.getDeployedProcessDefinition(processDefId);
}
}