11月28日-课堂测验

1、设计思想
在DBUtil.java中连接数据库，然后用logonwindow.jsp写添加界面，logon.jsp写执行过程。其中用if语句判断输入内容是否符合要求。

2、源代码

package com.jaovo.msg.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBUtil {
    public static Connection getConnection() {
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
        } catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        String user = "root";
        String password = "root";
        String url = "jdbc:mysql://localhost:3306/jaovo_msg";
        Connection connection = null;
        try {
            connection = DriverManager.getConnection(url, user, password);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return connection;
    }
}

DBUtil.java

<%@page import = "com.jaovo.msg.util.DBUtil" %>
<%@page import = "java.sql.*" %>
<%@page import = "java.sql.PreparedStatement" %>

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<html>
<%
    String classname = request.getParameter("classname");
    String teacher = request.getParameter("teacher");
    String address = request.getParameter("address");
     
    if(classname == null){
        request.setAttribute("result", "请输入课程名称！");
%>
        <jsp:forward page = "logonwindow.jsp"></jsp:forward>
<%
    }     
    if(teacher.equals("王建民")||teacher.equals("刘立嘉")||teacher.equals("刘丹")||
            teacher.equals("王辉")||teacher.equals("杨子光")){
    } 
    else{
        request.setAttribute("result", "该教师不存在！");
%>
        <jsp:forward page = "logonwindow.jsp"></jsp:forward>
<%
    }
    if(address.startsWith("基教") || address.startsWith("一教") || address.startsWith("二教") ||
            address.startsWith("三教") ){
    } 
    else{
         request.setAttribute("result", "上课地址错误！");
         %>
                 <jsp:forward page = "logonwindow.jsp"></jsp:forward>
         <%
    }
    Connection connection = DBUtil.getConnection();
    //准备sql语句
    String sql = "select count(*) from kechengbiao where classname = ?";
    //创建语句传输对象
    PreparedStatement preparedStatement = null;
    ResultSet resultSet = null;
        preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setString(1, classname);
        //接收结果集
        resultSet = preparedStatement.executeQuery();
        //遍历结果集
        while(resultSet.next()) {
            if (resultSet.getInt(1) > 0) {
                 request.setAttribute("result", "该课程已添加！");
        %>
        <jsp:forward page = "logonwindow.jsp"></jsp:forward>
        <%          
            }
        }
        
        sql = "INSERT INTO kechengbiao(classname,teacher,address) VALUES (?,?,?) ";
        preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setString(1, classname);
        preparedStatement.setString(2, teacher);
        preparedStatement.setString(3, address);
        preparedStatement.execute();
    
      request.setAttribute("result", "添加完成");
    %>
    <jsp:forward page = "logonwindow.jsp"></jsp:forward>

</html>

logon.jsp

<%@page import = "com.jaovo.msg.util.DBUtil" %>
<%@page import = "java.sql.*" %>
<%@page import = "java.sql.PreparedStatement" %>

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<html>
<%
    String classname = request.getParameter("classname");
    String teacher = request.getParameter("teacher");
    String address = request.getParameter("address");
     
    if(classname == null){
        request.setAttribute("result", "请输入课程名称！");
%>
        <jsp:forward page = "logonwindow.jsp"></jsp:forward>
<%
    }     
    if(teacher.equals("王建民")||teacher.equals("刘立嘉")||teacher.equals("刘丹")||
            teacher.equals("王辉")||teacher.equals("杨子光")){
    } 
    else{
        request.setAttribute("result", "该教师不存在！");
%>
        <jsp:forward page = "logonwindow.jsp"></jsp:forward>
<%
    }
    if(address.startsWith("基教") || address.startsWith("一教") || address.startsWith("二教") ||
            address.startsWith("三教") ){
    } 
    else{
         request.setAttribute("result", "上课地址错误！");
         %>
                 <jsp:forward page = "logonwindow.jsp"></jsp:forward>
         <%
    }
    Connection connection = DBUtil.getConnection();
    //准备sql语句
    String sql = "select count(*) from kechengbiao where classname = ?";
    //创建语句传输对象
    PreparedStatement preparedStatement = null;
    ResultSet resultSet = null;
        preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setString(1, classname);
        //接收结果集
        resultSet = preparedStatement.executeQuery();
        //遍历结果集
        while(resultSet.next()) {
            if (resultSet.getInt(1) > 0) {
                 request.setAttribute("result", "该课程已添加！");
        %>
        <jsp:forward page = "logonwindow.jsp"></jsp:forward>
        <%          
            }
        }
        
        sql = "INSERT INTO kechengbiao(classname,teacher,address) VALUES (?,?,?) ";
        preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setString(1, classname);
        preparedStatement.setString(2, teacher);
        preparedStatement.setString(3, address);
        preparedStatement.execute();
    
      request.setAttribute("result", "添加完成");
    %>
    <jsp:forward page = "logonwindow.jsp"></jsp:forward>

</html>

logonwindow.jsp

3、运行结果截图

4、