软件工程概论课堂练习添加课程信息

设计思路：

想要实现这个功能，首先要连接数据库，在jsp页面中输入内容，通过调用函数，获取输入的内容，然后通过数据库的执行语句将其存进数据库的表中。

还要判断输入的内容是否为空、是否是要求的内容。

源代码：

package bean;

public class Msg {
    String classname;
    String place;
    String teacher;
    public String getClassname() {
        return classname;
    }
    public void setClassname(String classname) {
        this.classname = classname;
    }
    public String getPlace() {
        return place;
    }
    public void setPlace(String place) {
        this.place = place;
    }
    public String getTeacher() {
        return teacher;
    }
    public void setTeacher(String teacher) {
        this.teacher = teacher;
    }
    

}

实现功能：

package dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import util.ClassException;

import bean.Msg;
import util.DButil;

public class ClassMsg {
    
    public void add(Msg  msg)
    {

                Connection connection = DButil.getConnection();
                PreparedStatement preparedStatement = null;
              try {
                
                    String sql = "insert into class_msg (classname,teacher,place) value (?,?,?)";
                    preparedStatement = connection.prepareStatement(sql);
                    preparedStatement.setString(1, msg.getClassname());
                    preparedStatement.setString(2,msg.getTeacher());
                    preparedStatement.setString(3,msg.getPlace());
                    
                    preparedStatement.executeUpdate();
                } catch (SQLException e) {

                    e.printStackTrace();
                }finally {

                    DButil.close(connection);
                }
        
    }
    
    
    

}

异常：

package util;

public class ClassException extends RuntimeException{
    public ClassException() {
        super();
        // TODO Auto-generated constructor stub
    }

    public ClassException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
        // TODO Auto-generated constructor stub
    }

    public ClassException(String message, Throwable cause) {
        super(message, cause);
        // TODO Auto-generated constructor stub
    }

    public ClassException(String message) {
        super(message);
        // TODO Auto-generated constructor stub
    }

    public ClassException(Throwable cause) {
        super(cause);
        // TODO Auto-generated constructor stub
    }

}

链接数据库：

package util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DButil {
    public static Connection getConnection()
    {
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
        } catch (InstantiationException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        String user="****";
        String password="****";
        String url = "jdbc:mysql://localhost:3306/user_msg";
        Connection connection=null;
        try {
            connection=DriverManager.getConnection(url,user,password);
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        
        return connection;
    }
    
    public static void close(Connection connection)
    {
        try {
            connection.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }
    public static void close(PreparedStatement preparedStatement)
    {
        try {
            preparedStatement.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }
    public static void close(ResultSet resultSet)
    {
        try {
            resultSet.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }

}

判断输入是否为空并返回为空的结果：

package util;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

public class ValidateUtil {
    
    public static  boolean validateNull(HttpServletRequest request,String[] fileds) {
    
        boolean validate = true;
        //map对象用来装载不同的错误信息
        Map<String,String> errorMsg = new  HashMap();
        for(String filed :fileds) {
            String value = request.getParameter(filed);
            if (value == null || "".equals(value.trim())) {
                validate = false;
                errorMsg.put(filed, "这一行不能为空！");
            }
            if (!validate) {
                request.setAttribute("errormsg", errorMsg);
            }
            
        }
        
        return validate;
    }
    public static String showError(HttpServletRequest request , String filed) {
        Map<String, String> errorMsg = (Map<String,String>)request.getAttribute("errormsg");
        if (errorMsg == null) {
            return "";
        }
        String msg = errorMsg.get(filed);
        if (msg == null) {
            return "";
        }
        return msg;
    }

}

页面：

<%@page import="java.util.Map"%>
<%@page import="util.ValidateUtil"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>添加课程</title>
</head>
<body style="background-image:url('../image/back.jpg');">
<%Map<String,String> errorMsg = (Map<String,String>)request.getAttribute("errormsg"); 
%>
<form  action="add2.jsp" method="get">

<br>
<center style="color:black ; font-family:楷体;font-size:15px" > 课程名称:<input  type="text"  name="classname" /><%= ValidateUtil.showError(request, "classname") %></center>

<br>
<center style="color:black ; font-family:楷体;font-size:15px" > 任课教师:<input  type="text"  name="teacher" /><%= ValidateUtil.showError(request, "teacher") %></center>

<br>
<center style="color:black ; font-family:楷体;font-size:15px" > 上课地点:<input  type="text"  name="place" /><%= ValidateUtil.showError(request, "place") %></center>

<br>
<center><input type="submit" value="提交"  /> </center>
</form>

</body>
</html>

页面：

<%@page import="util.ValidateUtil"%>
<%@page import="util.ClassException"%>
<%@page import="bean.Msg"%>
<%@page import="dao.ClassMsg"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>添加课程</title>
</head>
<body style="background-image:url('../image/back.jpg');">
<%
    //接收客户端传递过来的参数
    String classname = request.getParameter("classname");
    String teacher = request.getParameter("teacher");
    String place = request.getParameter("place");
    
    boolean validate = ValidateUtil.validateNull(request, new String[]{"classname","teacher","place"});
    if(!validate){
    
%>
<jsp:forward page="add.jsp"></jsp:forward>
<%
    }
    if(!place.startsWith("基教")&&!place.startsWith("一教")&&!place.startsWith("二教")&&!place.startsWith("三教"))
    {
        %>
        <script language='javaScript' > alert('没有这个教室\n请重新输入！');window.history.back(-1);</script>
        <% 
    }
    else if(!teacher.equals("王建民")&&!teacher.equals("刘立嘉")&&!teacher.equals("刘丹")&&!teacher.equals("王辉")&&!teacher.equals("杨子光"))
    {
        %>
        <script language='javaScript' > alert('没有这个老师！\n请重新输入');window.history.back(-1);</script>
        <% 
    }
    else
    {
           Msg msg=new Msg();
           msg.setClassname(classname);
           msg.setTeacher(teacher);
           msg.setPlace(place);
           ClassMsg cm=new ClassMsg();
    
         
           cm.add(msg);
        
%>
    <center>保存成功!!<br></center>
    <center><a href="add.jsp">继续添加</a></center>
<% 

    }
    %>
</body>
</html>