大二暑假暑期第一周总结
大二暑期第一周
整理本次小学期第一阶段算法题
优化第二阶段的管理系统
以下为优化代码
package com.dao; import com.database.Jdbc; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.SQLException; public class LeasonDao { public void deleteleason(String str)//删除 { Connection connection = Jdbc.getConnection(); PreparedStatement preparedStatement=null; try { String sql = "delete from 选课表 where 课程名称 = ?"; preparedStatement=connection.prepareStatement(sql); preparedStatement.setString(1,str); preparedStatement.executeUpdate(); System.out.println("删除成功"); } catch (SQLException e) { e.printStackTrace(); }finally{ Jdbc.close(preparedStatement); Jdbc.close(connection); } } public void addleason( String str1, String str2, String str3, String str4, String str5) { Connection connection = Jdbc.getConnection(); PreparedStatement preparedStatement=null; try { String sql = "insert into 选课表 (课程名称,授课教师,课程节次,最大人数,教师工号) values (?,?,?,?,?)"; preparedStatement=connection.prepareStatement(sql); preparedStatement.setString(1,str1); preparedStatement.setString(2,str2); preparedStatement.setString(3,str3); preparedStatement.setString(4,str4); preparedStatement.setString(5,str5); preparedStatement.executeUpdate(); System.out.println("添加成功"); } catch (SQLException e) { e.printStackTrace(); }finally{ Jdbc.close(preparedStatement); Jdbc.close(connection); } } } package com.database; import java.sql.*; public class Jdbc { public static Connection getConnection()//连接数据库 { try{ Class.forName("com.mysql.cj.jdbc.Driver"); //System.out.println("加载驱动成功"); }catch(ClassNotFoundException e) { e.printStackTrace(); } String user="root"; String password="123456"; String url = "jdbc:mysql://localhost:3306/kecheng1?useSSL=false&serverTimezone=GMT&characterEncoding=utf-8&autoReconnect=true"; java.sql.Connection con=null; try{ con= DriverManager.getConnection(url,user,password); // System.out.println("数据库连接成功"); }catch(SQLException e) { e.printStackTrace(); } return con; } public static void close (Connection con) { try{ if(con!=null) { con.close(); } }catch(SQLException e) { e.printStackTrace(); } } public static void close(PreparedStatement preparedStatement) { try{ if(preparedStatement!=null) { preparedStatement.close(); } }catch(SQLException e) { e.printStackTrace(); } } public static void close(ResultSet resultSet) { try{ if(resultSet!=null) { resultSet.close(); } }catch(SQLException e) { e.printStackTrace(); } } } package com.servlet; import com.dao.TeacherDao; import com.dao.UserDao; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet("/indexservlet") public class indexservlet extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { req.setCharacterEncoding("utf-8"); String know = req.getParameter("action"); UserDao userDao = new UserDao(); TeacherDao teacherDao = new TeacherDao(); if (know.equals("userlogin")) {//登录 String usertype = req.getParameter("usertype"); String usernumber = req.getParameter("usernumber"); String userlocal = req.getParameter("userlocal"); if (userDao.surepassword(usertype, usernumber, userlocal) == 1 && usertype.equals("student")) { req.setAttribute("usernumber", usernumber); req.getRequestDispatcher("test").forward(req, resp); } if (userDao.surepassword(usertype, usernumber, userlocal) == 1 && usertype.equals("guanli")) { req.setAttribute("usernumber", usernumber); req.getRequestDispatcher("test1").forward(req, resp); } if (userDao.surepassword(usertype, usernumber, userlocal) == 1 && usertype.equals("teacher")) { req.setAttribute("usernumber", usernumber); req.getRequestDispatcher("test5").forward(req, resp); } } if(know.equals("teacherrevise")) { String studentnumber=(String)req.getSession().getAttribute("studentnumber"); String leassonname=(String)req.getSession().getAttribute("leassonname"); String teachernumber=(String)req.getSession().getAttribute("teachernumber"); String score = req.getParameter("score"); teacherDao.revise(studentnumber,leassonname,score); req.setAttribute("teachernumber", teachernumber); req.getRequestDispatcher("test7").forward(req, resp); } } @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } } package com.servlet; import com.bean.Student; import com.database.Jdbc; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.net.URLEncoder; import java.sql.*; import java.util.ArrayList; import java.util.List; @WebServlet("/test") //新闻详情 public class test extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ResultSet rs = null; Connection connection = Jdbc.getConnection(); PreparedStatement preparedStatement=null; String usernumber = (String) request.getAttribute("usernumber"); List<Student> userInfos = new ArrayList<>(); try { String sql="SELECT * FROM 学生选课表 where 学生学号 = ?"; preparedStatement=connection.prepareStatement(sql); preparedStatement.setString(1,usernumber); rs=preparedStatement.executeQuery(); while (rs.next()) { Student userInfo = new Student(); userInfo.setStudentclass(rs.getString("课程名称")); userInfo.setStudentteacher(rs.getString("授课教师")); userInfo.setStudenttime(rs.getString("开课节次")); userInfos.add(userInfo); } request.setAttribute("userInfos", userInfos); request.setAttribute("usernumber", usernumber); request.getRequestDispatcher("/student.jsp").forward(request, response); } catch (Exception e) { e.printStackTrace(); } finally { // 关闭资源 if (rs != null) { try { rs.close(); } catch (SQLException e) {} } if (preparedStatement != null) { try { preparedStatement.close(); } catch (SQLException e) {} } if (connection != null) { try { connection.close(); } catch (SQLException e) {} } } } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req, resp); } }
