2

src/com/controller/deptadmin/DeptAddStuPunchServlet.java

@@ -5,56 +5,61 @@ import com.dao.DeptAdminDao;
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
-import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletRequest;//fdsfdsfds2542354823
 import javax.servlet.http.HttpServletResponse;
-import java.io.IOException;
+import java.io.IOException; //导入IO异常和日期类
 import java.util.Date;
 
 @WebServlet("/DeptAddStuPunchServlet")
-public class DeptAddStuPunchServlet extends HttpServlet {
+public class DeptAddStuPunchServlet extends HttpServlet {  //定义一个继承自HttpServlet的Servlet类。
 
     @Override
-    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {  //重写doGet方法，处理HTTP GET请求。
+        //统一请求和响应的字符编码为UTF-8，防止中文乱码，并设置响应内容类型为HTML。
         req.setCharacterEncoding("utf-8");
         resp.setCharacterEncoding("utf-8");
         resp.setContentType("text/html;charset=utf-8");
 
         //获取表单请求的参数
-        String sno = req.getParameter("sno");
-        String sispunch = req.getParameter("sispunch");
-        String spunchdate = req.getParameter("spunchdate");
-        String spunchtime = req.getParameter("spunchtime");
-        String sishot = req.getParameter("sishot");
-        String siscough = req.getParameter("siscough");
-        String sisseem = req.getParameter("sisseem");
-        String sisdiagnose = req.getParameter("sisdiagnose");
-        String sstatus = req.getParameter("sstatus");
+        String sno = req.getParameter("sno"); //从 HTTP 请求中获取参数名为 "sno" 的值，并将其赋值给 sno 变量
+        String sispunch = req.getParameter("sispunch");//从 HTTP 请求中获取参数名为 "sispunch" 的值，并将其赋值给 sispunch 变量
+        String spunchdate = req.getParameter("spunchdate");//从 HTTP 请求中获取参数名为 "spunchdate" 的值，并将其赋值给 spunchdate 变量
+        String spunchtime = req.getParameter("spunchtime");//从 HTTP 请求中获取参数名为 "spunchtime" 的值，并将其赋值给 spunchtime 变量
+        String sishot = req.getParameter("sishot");//从 HTTP 请求中获取参数名为 "sishot" 的值，并将其赋值给 sishot 变量
+        String siscough = req.getParameter("siscough");//从 HTTP 请求中获取参数名为 "siscough" 的值，并将其赋值给 siscough 变量
+        String sisseem = req.getParameter("sisseem");//从 HTTP 请求中获取参数名为 "sisseem" 的值，并将其赋值给 sisseem 变量
+        String sisdiagnose = req.getParameter("sisdiagnose");//从 HTTP 请求中获取参数名为 "sisdiagnose" 的值，并将其赋值给 sisdiagnose 变量
+        String sstatus = req.getParameter("sstatus");//从 HTTP 请求中获取参数名为 "sstatus" 的值，并将其赋值给 sstatus 变量
 
         String sql = null;
-
+        //声明SQL语句变量，并输出调试信息
         System.out.println("shgshgh");
 
         //查询是否存在此人
-        sql = "select count(*) as num from stupunchin where sno = ? and spunchdate = ?";
-        Object[] objects = {sno, spunchdate};
-        int count = DeptAdminDao.findTotalCount(sql, objects);
+        sql = "select count(*) as num from stupunchin where sno = ? and spunchdate = ?";//检查stupunchin表中是否存在相同学号和日期的记录
+        Object[] objects = {sno, spunchdate};   //使用Object数组传递参数，防止SQL注入。
+        int count = DeptAdminDao.findTotalCount(sql, objects);//调用DAO方法findTotalCount返回匹配记录数。
 
-        if (count == 0){//无则操作
+        if (count == 0){//条件判断：如果不存在重复记录（count为0），执行插入操作。
             sql = "insert into stupunchin values(?, ?, ?, ?, ?, ?, ?, ?, ?)";
             Object[] objects1 = {sno, sispunch, spunchdate, spunchtime, sishot, siscough, sisseem, sisdiagnose, sstatus};
+            //SQL插入语句：向stupunchin表插入包含9个字段的新记录
+            //参数绑定：将表单参数按顺序填入占位符
 
-            int num = DeptAdminDao.executeUpdate(sql, objects1);
+            int num = DeptAdminDao.executeUpdate(sql, objects1);//执行更新：调用DAO方法executeUpdate执行插入，返回受影响的行数。
 
             System.out.println(num);
 
             req.getRequestDispatcher("/DeptQueryStuPunchByPageServlet?currentPage=1&rows=7&sname=&sclass=&spunchdate=").forward(req, resp);
         }else {
-            req.getRequestDispatcher("/view/alluse/existdataofadd.jsp").forward(req, resp);
-        }
+            req.getRequestDispatcher("/view/alluse/existdataofadd.jsp").forward(req, resp);//转发请求：插入成功后，转发到分页查询Servlet，显示第一页数据（参数currentPage=1，每页7行）。
+        }//处理重复数据：如果记录已存在，转发到提示页面existdataofadd.jsp
     }
 
     @Override
     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
-        doGet(req, resp);
+        doGet(req, resp);//处理POST请求：重写doPost方法，直接调用doGet，统一处理GET和POST请求
+
+
     }
 }