java的MVC-模式的数据库增删改查.doc

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1、Four short words sum up what has lifted most successful individuals above the crowd: a little bit more.-author-datejava的MVC-模式的数据库增删改查攀枝花学院实验报告攀枝花学院实验报告实验课程:JAVA应用开发 实验项目：JSP操作数据库实验日期：2013.5 系：计算机 班级：10计本1班 姓名：蒋志勇 学号：201010801035指导老师：范胜波成绩：一 实验目的：1. 掌握JSP，servlet的基本应用。2. 掌握用JSP对数据库进行增，删，查，改操作。二 实验设备

2、Eclipse，Mysql数据库，Tomact三 实验内容1. 创建数据库javaee和表Users，Users的sql语句为： CREATE TABLE users ( id int(11) NOT NULL AUTO_INCREMENT, UserName varchar(30) NOT NULL, Password varchar(30) NOT NULL, PRIMARY KEY (id) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;2. 编写数据库连接、增、删、查、改类UserDao，核心代码如下：public class

3、UserDao final static String url = jdbc:mysql:/localhost:3306/javaee?useUnicode=true&characterEncoding=UTF-8;final static String user = root;final static String password = 123456;static try Class.forName(com.mysql.jdbc.Driver); catch (ClassNotFoundException e) e.printStackTrace();/数据库连接private Connec

4、tion getConnection() throws SQLException Connection conn = DriverManager.getConnection(url, user, password);return conn;/根据ID删除用户public boolean delUser(int id)boolean flag=false;String addUserSQL=DELETE FROM Users WHERE ID=?;Connection conn = null;PreparedStatement pst = null;try conn=getConnection(

5、);pst=conn.prepareStatement(addUserSQL);pst.setInt(1, id);flag=(pst.executeUpdate()=1); catch (SQLException e) e.printStackTrace();finallytry pst.close();conn.close(); catch (SQLException e) e.printStackTrace();return flag;/增加用户public boolean addUser(User newUser)boolean flag=false;String addUserSQL

6、=INSERT INTO Users(UserName,Password) VALUES(?,?);Connection conn = null;PreparedStatement pst = null;try conn=getConnection();pst=conn.prepareStatement(addUserSQL);pst.setString(1, newUser.getUserName();pst.setString(2, newUser.getPassword();flag=(pst.executeUpdate()=1); catch (SQLException e) e.pr

7、intStackTrace();finallytry pst.close();conn.close(); catch (SQLException e) e.printStackTrace();return flag;/分页查询用户public List getUser(int startIndex,int count) List userList = new ArrayList();String getUserSQL = SELECT ID,UserName,Password FROM Users ORDER BY ID Desc LIMIT ?,?;Connection conn = nul

8、l;PreparedStatement pst = null;ResultSet rs = null;try conn = getConnection();pst = conn.prepareStatement(getUserSQL);pst.setInt(1, startIndex);pst.setInt(2, count);rs = pst.executeQuery();while (rs.next() User u = new User(rs.getInt(ID), rs.getString(UserName),rs.getString(Password);userList.add(u)

9、; catch (SQLException e) e.printStackTrace();finallytry rs.close();pst.close();conn.close(); catch (SQLException e) e.printStackTrace();return userList;/更新用户数据public boolean updateUser(String userName,String password,int id)boolean flag=false;String SQL=update Users set UserName=?, Password=? where

10、id=?;Connection conn = null;PreparedStatement pst = null;try conn=getConnection();pst=conn.prepareStatement(SQL);System.out.println(userName);System.out.println(password);pst.setString(1, userName);pst.setString(2, password);pst.setInt(3, id);flag=(pst.executeUpdate()=1);System.out.println(flag); ca

11、tch (SQLException e) e.printStackTrace();finallytry pst.close();conn.close(); catch (SQLException e) e.printStackTrace();return flag; 3. 编写控制类SaveUserServlet.java和查询雷ListUserServlet.java，代码如下。SaveUserServlet代码：public class SaveUserServlet extends HttpServlet private static final long serialVersionUI

12、D = -5350720307591869348L;Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException doAction(request, response);Overrideprotected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOExceptio

13、n System.out.println(Do Get.);doAction(request, response);private void doAction(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException String action = request.getParameter(action);if (action = null) return;if (action.equals(add) add(request, response); else if

14、(action.equals(update) update(request, response); else if (action.equals(del) del(request, response); else if (action.equals(load) load(request, response);/ 增加用户private void add(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException System.out.println(add);resp

15、onse.setCharacterEncoding(utf-8);String userName =new String(request.getParameter(UserName).getBytes(ISO-8859-1),utf-8)；String password = request.getParameter(Password);User u = new User(userName, password);UserDao dao = new UserDao();if (dao.addUser(u) response.sendRedirect(listUser); else throw ne

16、w RuntimeException(Add Use ERRO);/ 更新用户private void update(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException response.setCharacterEncoding(utf-8);response.setHeader(content-type,text/html;charset=UTF-8);System.out.println(update.);String idStr = request.ge

17、tParameter(id);int select = Integer.parseInt(request.getParameter(select);if (select = 1) if (idStr != null) int id = Integer.parseInt(idStr);UserDao dao = new UserDao();User user = dao.getUserById(id);request.setAttribute(idUser, user);RequestDispatcher update = request.getRequestDispatcher(updateU

18、ser.jsp);update.forward(request, response);else if(select=2)String userName=new String(request.getParameter(userName).getBytes(ISO-8859-1),utf-8)；String password=request.getParameter(password);int id=Integer.parseInt(idStr);UserDao dao=new UserDao();boolean flag=dao.updateUser(userName, password, id

19、);if(flag=true)response.sendRedirect(listUser);elsethrow new RuntimeException(update Use ERRO);/ 删除用户private void del(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException System.out.println(del);String idStr = request.getParameter(id);if (idStr != null) int i

20、d = Integer.parseInt(idStr);UserDao dao = new UserDao();if (dao.delUser(id) int curPage = 1;String curPageStr = request.getParameter(curpage);if (curPageStr != null) curPage = Integer.parseInt(curPageStr);int count = 3;String countStr = request.getParameter(count);if (countStr != null) count = Integ

21、er.parseInt(countStr);response.sendRedirect(listUser?curpage= + curPage + &count=+ count); else throw new RuntimeException(Add Use ERRO);ListUserServlet代码：public class ListUserServlet extends HttpServlet private static final long serialVersionUID = 1L; public ListUserServlet() super(); protected voi

22、d doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException int curPage=1;String curPageStr=request.getParameter(curpage);if(curPageStr!=null)curPage=Integer.parseInt(curPageStr);int count=3; /每页显示数目String countStr=request.getParameter(count);if(countStr!=n

23、ull)count=Integer.parseInt(countStr);int startIndex=(curPage-1)*count;UserDao dao=new UserDao();List users=dao.getUser(startIndex, count);request.setAttribute(USERS, users);int userCount=dao.countUser();/数据库总共记录数int pageCount=userCount%count=0?userCount/count:userCount/count+1;request.setAttribute(c

24、urpage, curPage);/当前页request.setAttribute(count, count);/每页记录数request.setAttribute(PAGECOUNT, pageCount);/request.getRequestDispatcher(User.jsp).forward(request, response);4. 编写AddUser.jsp添加用户信息，User.jsp查看和删除用户信息，updateUser.jsp修改用户信息。（1） AddUser.jsp核心代码：Add UserUserName:Password:界面为：（2） User.jsp核心代码

25、用户IDUserNamePasswordOperation$user.id$user.userName$user.passwordDelUpdateAdd$p 界面如下所示（3） updateUser.jsp核心代码：更新用户UserName:Password:四 实验总结这次实验中学会了用MVC设计模式，分别编写JSP，Servlet，Dao类对数据库表的增、删、查、改。学会了怎样配置Servlet的web.xml文件，jstl和el表达式的使用。知道了一种新的数据分页分页方式通过SQL语句的“LIMIT ?,?”方法。在实验中存在的问题是Servlet中sendRedirect和forward的两种用法没弄清楚，因此在编写update（）方法时很久都没把查询出的数据显示出来。-