一个使用java 写的进销存代码 使用了ejb 等技术 是学习j2ee的好

				package servlet;
				
				import javax.servlet.*;
				import javax.servlet.http.*;
				import java.io.*;
				import java.util.*;
				import data.*;
				import method.DataMethod;
				
				public class UserLogView extends HttpServlet {
				  private static final String CONTENT_TYPE = "text/html; charset=GBK";
				  public void init() throws ServletException {
				  }
				  public void doPost(HttpServletRequest request, HttpServletResponse response) throws
				      ServletException, IOException {
				    //设置取得字符串的编码机制
				    request.setCharacterEncoding("GBK");
				    //设置字符输出的编码机制
				    response.setContentType(CONTENT_TYPE);
				    //取得html代码输出类
				    PrintWriter out = response.getWriter();
				    //通过HttpServlet类的getServletContext方法取得application的对象
				    ServletContext application = getServletContext();
				    //创建session对象
				    HttpSession session = request.getSession();
				    //声明页面转向类
				    RequestDispatcher requestDispatcher = null;
				    //创建数据类
				    StockManagementData stockManagementData = new StockManagementData();
				    //创建用户日志数组
				    String[][] userLog = new String[0][5];
				    //创建方法类
				    DataMethod dataMethod = new DataMethod();
				    //根据传入参数取得用户日志数组
				    if(request.getParameter("selectedIndex") != null){
				      int selectedIndex = Integer.parseInt(request.getParameter("selectedIndex"));
				      String searchValue = request.getParameter("searchValue");
				      if(selectedIndex == 0 | selectedIndex == 1 | selectedIndex == 2){
				        if(searchValue.length() == 0){
				          out.print("查询值为空，请重新输入.");
				          return;
				        }
				      }
				      switch (selectedIndex) {
				        case 0:
				          //根据操作程序名字取得用户日志数组
				          userLog = stockManagementData.getUserLogByProgramName(searchValue);
				          break;
				        case 1:
				          //根据操作内容取得用户日志数组
				          userLog = stockManagementData.getUserLogByOperationContent(searchValue);
				          break;
				        case 2:
				          //根据用户名字取得用户日志数组
				          userLog = stockManagementData.getUserLogByUserName(searchValue);
				          break;
				        case 3:
				          /*根据操作时间取得用户日志数组*/
				          //取得日期变量
				          String startDateStr = request.getParameter("startDate");
				          String endDateStr = request.getParameter("endDate");
				          //创建日期变量
				          int[] startDateInts = new int[3];
				          int[] endDateInts = new int[3];
				          Calendar startCalendar = Calendar.getInstance();
				          Calendar endCalendar = Calendar.getInstance();
				          java.sql.Timestamp startDate = null;
				          java.sql.Timestamp endDate = null;
				          /*检查开始日期字符串*/
				          //创建日期类
				          Calendar date = Calendar.getInstance();
				          //创建默认的日期格式的DateFormat类
				          java.text.DateFormat dateFormat1 = java.text.DateFormat.getDateInstance();
				          try{
				            date.setTime(dateFormat1.parse(startDateStr));
				            startDateInts[0] = date.get(Calendar.YEAR);
				            startDateInts[1] = date.get(Calendar.MONTH);
				            startDateInts[2] = date.get(Calendar.DAY_OF_MONTH);
				          }catch(Exception ex){
				            startDateInts[0] = -1;
				          }
				          if(startDateInts[0] == -1){
				            out.print("开始日期输入错误，正确的日期格式是yyyy-mm-dd（年-月-日），如2004-1-1"
				                    + "请重新输入.");
				            return;
				          }
				          //取得开始日期
				          startCalendar.set(startDateInts[0], startDateInts[1], startDateInts[2],
				                            0, 0, 0);
				          startDate = new java.sql.Timestamp(startCalendar.getTime().getTime());
				          //如果结束日期字符为空,显示开始日期至当前日期的记录
				          if(endDateStr.length() == 0){
				            endDate = new java.sql.Timestamp(endCalendar.getTime().getTime());
				          }else{
				            //检查结束日期字符串
				            endDateInts = dataMethod.checkDate(endDateStr);
				            try{
				              date.setTime(dateFormat1.parse(endDateStr));
				              endDateInts[0] = date.get(Calendar.YEAR);
				              endDateInts[1] = date.get(Calendar.MONTH);
				              endDateInts[2] = date.get(Calendar.DAY_OF_MONTH);
				            }catch(Exception ex){
				              endDateInts[0] = -1;
				            }
				            if(endDateInts[0] == -1){
				              out.print("结束日期输入错误，正确的日期格式是yyyy-mm-dd（年-月-日），如2004-1-1"
				                      + "请重新输入.");
				              return;
				            }
				            //取得结束日期
				            endCalendar.set(endDateInts[0], endDateInts[1], endDateInts[2], 23, 59, 59);
				            endDate = new java.sql.Timestamp(endCalendar.getTime().getTime());
				          }
				          //根据日期取得用户日志记录
				          userLog = stockManagementData.getUserLogByOperationDate(startDate, endDate);
				          break;
				      }
				    }
				    //创建页面转向类
				    requestDispatcher = application.getRequestDispatcher("/userlogview.jsp");
				    //将数组放入request对象
				    request.setAttribute("userLog", userLog);
				    requestDispatcher.forward(request, response);
				  }
				  public void destroy() {
				  }
				}