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);
    }
}