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  • 问题与思考6

    网络系统都需要哪些技术:

    JSP基础,JSP动作指令,JavaBean, JDBC, 表达试语言,国际化、标准标签库,MVC模式,数据库链接

    JSP用于显示,servlet用于控制,JSP主要完成与用户的交互过程,不应该包括处理代码和控制代码

    课堂测试代码:

       package com.jaovo.msg.dao;

    import java.util.List;

    import com.jaovo.msg.model.User;

    public interface IUserDao {

           public void add(User user);

           public void delete(int id);

           public void update(User user);

           public User load(int id);

           public User load(String username);

           public List<User> load();

          

    }

    package com.jaovo.msg.dao;

    import java.sql.Connection;

    import java.sql.PreparedStatement;

    import java.sql.ResultSet;

    import java.sql.SQLException;

    import java.util.ArrayList;

    import java.util.List;

    import com.jaovo.msg.Util.DBUtil;

    import com.jaovo.msg.Util.UserException;

    import com.jaovo.msg.model.User;

    //import sun.net.www.content.text.plain;

    public class UserDaoImpl implements IUserDao {

           @Override

           public void add(User user) {

                  //鑾峰緱閾炬帴瀵硅薄

                  Connection connection = DBUtil.getConnection();

                  //鍑嗗�sql璇�彞

                  String sql = "select count(*) from t_user where username = ?";

                  //鍒涘缓璇�彞浼犺緭瀵硅薄

                  PreparedStatement preparedStatement = null;

                  ResultSet resultSet = null;

                  try {

                         preparedStatement = connection.prepareStatement(sql);

                         preparedStatement.setString(1, user.getUsername());

                         //鎺ユ敹缁撴灉闆?

                         resultSet = preparedStatement.executeQuery();

                         //閬嶅巻缁撴灉闆?

                         while(resultSet.next()) {

                                if (resultSet.getInt(1) > 0) {

                                       throw new UserException("用户已经存在") ;

                                }

                         }

                        

                         sql = "insert into t_user(username,password,nickname) value (?,?,?)";

                         preparedStatement = connection.prepareStatement(sql);

                         preparedStatement.setString(1, user.getUsername());

                         preparedStatement.setString(2, user.getPassword());

                         preparedStatement.setString(3, user.getNickname());

                         preparedStatement.executeUpdate();

                  } catch (SQLException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }finally {

                         //鍏抽棴璧勬簮

                         DBUtil.close(resultSet);

                         DBUtil.close(preparedStatement);

                         DBUtil.close(connection);

                  }

                 

           }

           @Override

           public void delete(int id) {

                  Connection connection = DBUtil.getConnection();

                  String sql = "delete from t_user where id = ?";

                  PreparedStatement preparedStatement = null;

                 

                  try {

                         preparedStatement = connection.prepareStatement(sql);

                         preparedStatement.setInt(1, id);

                         preparedStatement.executeUpdate();

                  } catch (SQLException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }finally {

                         DBUtil.close(preparedStatement);

                         DBUtil.close(connection);

                  }

                 

           }

           @Override

           public void update(User user) {

                  Connection connection = DBUtil.getConnection();

                  //鍑嗗�sql璇�彞

                  String sql = "update t_user set password = ? , nickname=? where id = ?";

                  //鍒涘缓璇�彞浼犺緭瀵硅薄

                  PreparedStatement preparedStatement = null;

                  try {

                         preparedStatement = connection.prepareStatement(sql);

                         preparedStatement.setString(1, user.getPassword());

                         preparedStatement.setString(2, user.getNickname());

                         preparedStatement.setInt(3, user.getId());

                         preparedStatement.executeUpdate();

                  } catch (SQLException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }finally {

                         DBUtil.close(preparedStatement);

                         DBUtil.close(connection);

                  }

           }

           @Override

           public User load(int id) {

                  Connection connection = DBUtil.getConnection();

                  //鍑嗗�sql璇�彞

                  String sql = "select * from t_user  where id = ?";

                  //鍒涘缓璇�彞浼犺緭瀵硅薄

                  PreparedStatement preparedStatement = null;

                  ResultSet resultSet = null;

                  User user = null;

                  try {

                         preparedStatement = connection.prepareStatement(sql);

                         preparedStatement.setInt(1, id);

                         resultSet = preparedStatement.executeQuery();

                         while(resultSet.next()) {

                                user = new User();

                                user.setId(id);

                                user.setUsername(resultSet.getString("username"));

                                user.setPassword(resultSet.getString("password"));

                                user.setNickname(resultSet.getString("nickname"));

                         }

                  } catch (SQLException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }finally {

                         DBUtil.close(resultSet);

                         DBUtil.close(preparedStatement);

                         DBUtil.close(connection);

                  }

                  return  user;

           }

           @Override

           public User load(String username) {

                  // TODO Auto-generated method stub

                  return null;

           }

           @Override

           public List<User> load() {

                  Connection connection = DBUtil.getConnection();

                  //鍑嗗�sql璇�彞

                  String sql = "select * from t_user ";

                  //鍒涘缓璇�彞浼犺緭瀵硅薄

                  PreparedStatement preparedStatement = null;

                  ResultSet resultSet = null;

                  //闆嗗悎涓�彧鑳芥斁鍏�ser瀵硅薄

                  List<User> users = new ArrayList<User>();

                  User user = null;

                  try {

                         preparedStatement = connection.prepareStatement(sql);

                         resultSet = preparedStatement.executeQuery();

                         while(resultSet.next()) {

                                user = new User();

                                user.setId(resultSet.getInt("id"));

                                user.setUsername(resultSet.getString("username"));

                                user.setPassword(resultSet.getString("password"));

                                user.setNickname(resultSet.getString("nickname"));

                                users.add(user);

                         }

                  } catch (SQLException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }finally {

                         DBUtil.close(resultSet);

                         DBUtil.close(preparedStatement);

                         DBUtil.close(connection);

                  }

                  return  users;

           }

    }

    package com.jaovo.msg.model;

     

    public class User {

       

        private int id;

        private String  username;

        private String  nickname;

        private String  password;

        public int getId() {

            return id;

        }

        public void setId(int id) {

            this.id = id;

        }

        public String getUsername() {

            return username;

        }

        public void setUsername(String username) {

            this.username = username;

        }

        public String getNickname() {

            return nickname;

        }

        public void setNickname(String nickname) {

            this.nickname = nickname;

        }

        public String getPassword() {

            return password;

        }

        public void setPassword(String password) {

            this.password = password;

        }

       

    }

    package com.jaovo.msg.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 {

                         //1 鍔犺浇椹卞姩

                         Class.forName("com.mysql.jdbc.Driver").newInstance();

                  } catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }

                  String user = "root";

                  String password = "LQYroot";

                  String url = "jdbc:mysql://localhost:3306/jaovo_msg";

                  Connection connection = null;

                  try {

                         //2 鍒涘缓閾炬帴瀵硅薄connection

                          connection = DriverManager.getConnection(url,user,password);

                  } catch (SQLException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }

                  return connection;

           }

          

           //鍏抽棴璧勬簮鐨勬柟娉?

           public static void close(Connection connection ) {

                  try {

                         if (connection != null) {

                                connection.close();

                         }

                        

                  } catch (SQLException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }

           }

           public static void close(PreparedStatement preparedStatement ) {

                  try {

                         if (preparedStatement != null) {

                                preparedStatement.close();

                         }

                        

                  } catch (SQLException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }

           }

           public static void close(ResultSet resultSet ) {

                  try {

                         if (resultSet != null) {

                                resultSet.close();

                         }

                        

                  } catch (SQLException e) {

                         // TODO Auto-generated catch block

                         e.printStackTrace();

                  }

           }

          

    }

    package com.jaovo.msg.Util;

     

    public class UserException extends RuntimeException{

     

        /**

         *

         */

        private static final long serialVersionUID = 1L;

     

        public UserException() {

            super();

            // TODO Auto-generated constructor stub

        }

     

        public UserException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {

            super(message, cause, enableSuppression, writableStackTrace);

            // TODO Auto-generated constructor stub

        }

     

        public UserException(String message, Throwable cause) {

            super(message, cause);

            // TODO Auto-generated constructor stub

        }

     

        public UserException(String message) {

            super(message);

            // TODO Auto-generated constructor stub

        }

     

        public UserException(Throwable cause) {

            super(cause);

            // TODO Auto-generated constructor stub

        }

       

    }

    <%@ 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 lang="en">

    <head>

        <meta name="viewport" content="width=device-width, initial-scale=1">

        <link rel="stylesheet" href="http://code.jquery.com/mobile/1.3.2/jquery.mobile-1.3.2.min.css">

        <script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>

        <script src="http://code.jquery.com/mobile/1.3.2/jquery.mobile-1.3.2.min.js"></script>

        <title>用户添加页面</title>

        <style type="test/css">.box{

        700 px;

        height:352 px;

        margin:0 auto;

        backgrand:url(bbb.PNG)) no-repeat center;

    }</style>

    </head>

    <body>

        <div class="box"></div>

        <%=request.getAttribute("error") %>

        <form action="add.jsp" method="get">

            <table align="center" border="1" width="500">

               <tr>

                   <td>用户名称 :</td>

                   <td>

                       <input type="text" name="username" />

                   </td>

               </tr>

               <tr>

                   <td>用户密码:</td>

                   <td>

                       <input type="password" name="password" />

                   </td>

               </tr>

               <tr>

                  

               </tr>

               <tr align="center">

                   <td colspan="2">

                       <input type="submit" value="登录" />                

                   </td>

               </tr>

            </table>

        </form>

    </body>

    </html>

    <%@page import="com.jaovo.msg.Util.UserException"%>

    <%@page import="com.jaovo.msg.dao.UserDaoImpl"%>

    <%@page import="com.jaovo.msg.model.User"%>

    <%@ 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>

    <%

        //接收客户端传递过来的参数

        String username = request.getParameter("username");

        String password = request.getParameter("password");

        String nickname = request.getParameter("nickname");

        if(username == null || "".equals(username.trim())){

            request.setAttribute("error", "用户名不能为空");

       

    %>

        <jsp:forward page="addInput.jsp"></jsp:forward>

    <%

        }

        User user = new User();

        user.setUsername(username);

        user.setPassword(password);

        user.setNickname(nickname);

        UserDaoImpl userDao = new UserDaoImpl();

        try{

            //UserDaoImpl userDao = new UserDaoImpl();

        userDao.add(user);

        //重定向

    %>

     

       

       

    <%

        }catch(UserException e){

    %>

        <h2 style="color:red ; font-size:50px">发生错误 : <%=e.getMessage() %></h2>

        <%

        }

        %>

    </html>

    运行截图:

     

    说明课堂测试未按时完成的原因:

       没有提前学习数据库方面的知识,上课时没有认真记笔记,记录eclipse的配置方法,课下也没有认真学习JSp方面的知识,总的来说自主学习能力不足。

    对这门课的希望和目标;

       实践中学习,实践中总结,锻炼独立解决问题的能力,勤于总结,善于合作,积极学习。

        计划每周有25小时的学习该门课程的时间。

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  • 原文地址:https://www.cnblogs.com/1605-3QYL/p/7881462.html
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