jBPM4之请假流程例子
最近项目需要工作流,所以就准备采用jBPM4作为工作流引擎，
才开始接触，很多东西都是一步一步摸索出来的，当然了，也搜索了一些文章，下面就是这两天使用jBPM4做的一个请假的例子.
流程比较简单，流程图如下：
本来作为才开始学习JBPM的人来说，最好的方法就是先运行起程序，然后学习就要方便很多。
下面是我的servlet文件;
package com.vito.jbpm.servlet;import java.io.IOException;import java.io.PrintWriter;import java.util.HashMap;import java.util.List;import java.util.Map;import java.util.Set;import javax.servlet.RequestDispatcher;import javax.servlet.ServletConfig;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import org.jbpm.api.Configuration;import org.jbpm.api.Execution;import org.jbpm.api.ExecutionService;import org.jbpm.api.ProcessDefinition;import org.jbpm.api.ProcessEngine;import org.jbpm.api.ProcessInstance;import org.jbpm.api.RepositoryService;import org.jbpm.api.TaskService;import org.jbpm.api.model.ActivityCoordinates;import org.jbpm.api.task.Task;/** * 请假流程Servlet * @author 周文滔 <zhouwentao16@gmail.com> * @time 2012-5-27 下午05:39:32 */public class LeaveServlet extends HttpServlet {private ProcessEngine processEngine = null;private RepositoryService repositoryService = null;private ExecutionService executionService = null;private ProcessInstance processInstance = null;private TaskService taskService = null;public LeaveServlet() {super();}public void init(ServletConfig config) throws ServletException {super.init(config);// 获取流程引擎processEngine = new Configuration().buildProcessEngine();repositoryService = processEngine.getRepositoryService();executionService = processEngine.getExecutionService();taskService = processEngine.getTaskService();}public void destroy() {super.destroy(); // Just puts "destroy" string in log}public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {process(request, response);}protected void process(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String action = request.getParameter("action");HttpSession session = request.getSession();if (action.equals("leave")) {request.getRequestDispatcher("").forward(request, response);} else if (action.equals("list")) {String username = (String) session.getAttribute("username");List<ProcessDefinition> pdList = repositoryService.createProcessDefinitionQuery().list();List<ProcessInstance> piList = executionService.createProcessInstanceQuery().list();List<Task> taskList = taskService.findPersonalTasks(username);session.setAttribute("pdList", pdList);session.setAttribute("piList", piList);session.setAttribute("taskList", taskList);request.getRequestDispatcher("list.jsp").forward(request, response);}else if (action.equals("start")) {Map map = new HashMap();map.put("user",session.getAttribute("username"));executionService.startProcessInstanceById(request.getParameter("id"),map);request.getRequestDispatcher("leave?action=list").forward(request, response);}else if (action.equals("submit")) {String taskId = request.getParameter("taskId");int day = Integer.parseInt(request.getParameter("day"));String reason = request.getParameter("reason");reason = new String(reason.getBytes("ISO-8859-1"),"UTF-8");Map map = new HashMap();map.put("days", day);map.put("reason", reason);taskService.completeTask(taskId, "to_teacher",map);request.getRequestDispatcher("leave?action=list").forward(request, response);}else if (action.equals("view")) {String id = request.getParameter("id");processInstance = executionService.findProcessInstanceById(id);Set<String> activityNames = processInstance.findActiveActivityNames();ActivityCoordinates ac = repositoryService.getActivityCoordinates(processInstance.getProcessDefinitionId(),activityNames.iterator().next());request.setAttribute("ac", ac);request.getRequestDispatcher("view.jsp").forward(request, response);}else if (action.equals("deploy")) {repositoryService.createDeployment().addResourceFromClasspath("leave.jpdl.xml").deploy();}else if(action.equals("sh")){String taskId = request.getParameter("taskId");String result = request.getParameter("result");result = new String(result.getBytes("ISO-8859-1"), "UTF-8");System.out.println(result);taskService.completeTask(taskId, result);request.getRequestDispatcher("leave?action=list").forward(request, response);}}}好了，要想查看详细的源码，下载我上传的压缩包吧。
如果你使用的tomcat6， 出现java.lang.LinkageError这个错误的话，那么可以参考http://blog.csdn.net/ol_beta/article/details/5553473这个文章。
还有不要忘记添加JBPM的jar包哦