学习Java Web有一段时间了，借此机会和大家分享一个小东西——在线留言系统，虽然low，小喷即可，大喷伤心，还是希望大家的指正和意见，话不多说，直接上：
第一步：
①.写一个注册页面，这一个页面主要是用户的输入，比较简单，代码如下：
regist.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%>
<!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=GBK">
<title>注册页面</title>
</head>
<body>
<form method = "POST" action = "registdo.jsp">
用户名：<input type = "text" name= "username">
密码：<input type = "password" name = "userpass">
<input type = "submit" value = "注册">
<input type = "reset" value = "重置">
</form>
</body>
</html>效果如图：
②.下面这个页面主要负责用来处理业务逻辑以及显示注册的结果，代码如下：
registdo.jsp
<%@page import="com.szx.jnmc.UserDao"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="com.szx.jnmc.DBOper"%>
<%@page import="java.io.PrintWriter"%>
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%><%@page import="java.util.List"%><%@page import="com.szx.jnmc.User"%>
<!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=GBK">
<title>留言板</title>
</head>
<body>
<%request.setCharacterEncoding("GBK");response.setContentType("text/html;charset=gbk");/* PrintWriter out = response.getWriter(); */String username = request.getParameter("username");String userpass = request.getParameter("userpass");ServletContext ctx = this.getServletContext();String server = ctx.getInitParameter("server");String dbname = ctx.getInitParameter("dbname");String dbuser = ctx.getInitParameter("dbuser");String dbpwd = ctx.getInitParameter("dbpwd");UserDao dao = new UserDao();User user = new User();user.setUsername(username);user.setUserpass(userpass);try{dao.getConn(server, dbname, dbuser, dbpwd);if(dao.addUser(user)){out.println("注册成功");out.println("<br><a href = 'login.jsp'>返回登陆</a></br>");}else{out.println("注册失败");out.println("<br><a href = 'regist.jsp'>返回注册</a></br>");}}catch(Exception e){e.printStackTrace();}
%>
</body>
</html>效果如图：
第二步：
①.这一步写个登录页面，主要用来接收用户输入的登录信息：代码如下：
login.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%>
<!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=GBK">
<title>留言板</title>
</head>
<body>
<form method = "POST" action = "logindo.jsp">
用户名：<input type = "text" name = "username">
密码：<input type = "password" name = "userpass">
<input type = "submit" value= "登录">
<input type = "reset"value = "重置">
</form>
</body>
</html>效果如图
②.这一步是需要写登录的逻辑及验证，并显示登录的结果，代码如下
logindo.jsp
<%@page import="java.sql.ResultSet"%>
<%@ page language="java" contentType="text/html; charset=gbk"pageEncoding="gbk"%><%@page import = "com.szx.jnmc.DBOper" %><%@page import = "javax.servlet.http.Cookie" %><%@page import = "javax.servlet.RequestDispatcher" %><%@page import = "javax.servlet.http.HttpSession" %>
<!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=gbk">
<title>留言板</title>
</head>
<body>
<%request.setCharacterEncoding("GBK");response.setContentType("text/html;charset=GBK");String username = request.getParameter("username");String userpass = request.getParameter("userpass");ServletContext ctx = request.getServletContext();String server = ctx.getInitParameter("server");String dbname = ctx.getInitParameter("dbname");String dbuser = ctx.getInitParameter("dbuser");String dbpwd = ctx.getInitParameter("dbpwd");DBOper db = new DBOper();String sql = "SELECT * FROM user Where username = ? AND userpass = ?";try{db.getConn(server, dbname, dbuser, dbpwd);ResultSet rs = db.executeQuery(sql, new String[]{username,userpass});if(rs!= null && rs.next()){session.setAttribute("username", username);Cookie cookie = new Cookie("username",username);cookie.setMaxAge(60*60*24*30);response.addCookie(cookie);RequestDispatcher dispatcher = request.getRequestDispatcher("userlist.jsp");dispatcher.forward(request, response);}else{out.println("登录失败！");out.println("<br><a href = 'login.jsp'>重新登录</a></br>");}}catch(Exception e){e.printStackTrace();}finally{db.closeAll();}
%>
</body>
</html>效果如图
前台的注册及登录页面到此已完成，下面我们接着做后台的数据
第二步
①.我们需要User类封装用户的信息，代码如下：
User.Java
package com.szx.jnmc;public class User {private int id;private String username;private String userpass;private String phone; private String email;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 getUserpass() {return userpass;}public void setUserpass(String userpass) {this.userpass = userpass;}public String getPhone() {return phone;}public void setPhone(String phone) {this.phone = phone;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}}
②.有了User类，就需要进行数据库的访问，这时候我们需要一个连接数据库的基础类，所有与连接数据库的类都要 继承于此，代码如下：
DBOper.Java
public Connection conn = null;public PreparedStatement ps = null;public ResultSet rs = null;/*** 连接数据库* @param server* @param dbname* @param dbuser* @param dbpwd* @return* @throws SQLException* @throws ClassNotFoundException*/public Connection getConn(String server,String dbname,String dbuser,String dbpwd) throws SQLException, ClassNotFoundException{ String DRIVER = "com.mysql.jdbc.Driver";String URL = "jdbc:mysql://" + server + ":3306/" + dbname + "?user="+ dbuser + "&password=" +dbpwd+"&useUnicode=true&characterEncoding=utf8";Class.forName(DRIVER);conn = DriverManager.getConnection(URL); return conn;}/*** 关闭数据库连接*/public void closeAll(){try{if(rs != null){rs.close();}}catch(SQLException e){e.printStackTrace();}finally{try{if(ps != null){ps.close();}}catch(SQLException e){e.printStackTrace(); }finally{try{if(conn != null){conn.close();}}catch(SQLException e){e.printStackTrace(); }}}}/*** 执行SQL语句，只进行查询，不进行增删改* @param preparedsql* @param param* @return*/public ResultSet executeQuery(String preparedsql,String[]param){try{ps = conn.prepareStatement(preparedsql);if(param != null){for (int i = 0; i < param.length; i++) {ps.setString(i + 1, param[i]);}}rs = ps.executeQuery();}catch(SQLException e){e.printStackTrace();}return rs;}/*** 执行sql语句，进行增删改，不进行查询* @param preparedsql* @param param* @return*/public int executeUpdate(String preparedsql,String[]param){int num = 0;try{ps = conn.prepareStatement(preparedsql);if(param != null){for (int i = 0; i < param.length; i++) {ps.setString(i + 1, param[i]);}}num = ps.executeUpdate();}catch(SQLException e){e.printStackTrace();}return num;}
}③.写完了数据库操作对象类，就要写用户 操作对象类代码如下，
UserDao.Java
package com.szx.jnmc;import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;public class UserDao extends DBOper{/*** 获取所有用户列表* @return*/public List<User> getAllUser(){List<User> userList = new ArrayList<User>();String sql = "Select *from user";try{ResultSet rs = this.executeQuery(sql,null);while(rs.next()){User user = new User(); user.setUsername(rs.getString("username"));user.setUserpass(rs.getString("userpass")); userList.add(user);}}catch(SQLException e){e.printStackTrace();}return userList; }/*** 根据用户名获取用户信息* @param name* @return*/public User getUserByName(String name){User user = new User();String sql = "SELECT * FROM user Where username = ?";try{ResultSet rs = this.executeQuery(sql, new String []{name});if(rs.next()){user.setEmail(rs.getString("email"));user.setId(rs.getInt("id"));user.setPhone(rs.getString("phone"));user.setUsername(rs.getString("username"));user.setUserpass(rs.getString("userpass"));}}catch(SQLException e){e.printStackTrace();}return user;} /*** 添加用户* @param user* @return*/public boolean addUser(User user){boolean r = false;String sql = "INSERT INTO user(username,userpass)VALUES(?,?)";try{int num = this.executeUpdate(sql,new String []{user.getUsername(),user.getUserpass()});if(num > 0){r = true;}}catch(Exception e){e.printStackTrace();} return r; }
}
④.我们的留言Message类，代码如下：
Message.Java
package com.szx.jnmc;public class Message {private int messageid;private String title;private String context;private String lefttime;private String wholeft;public String getWholeft() {return wholeft;}public void setWholeft(String wholeft) {this.wholeft = wholeft;}public int getMessageid() {return messageid;}public void setMessageid(int messageid) {this.messageid = messageid;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public String getContext() {return context;}public void setContext(String context) {this.context = context;}public String getLefttime() {return lefttime;}public void setLefttime(String lefttime) {this.lefttime = lefttime;}
}
⑤.留言数据操作对象MsgDao类，代码如下：
MsgDao.Java
package com.szx.jnmc;import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;public class MsgDao extends DBOper {/*** 获取所有留言* @return*/public List<Message> getAllMsg(){ List<Message> msglist = new ArrayList<Message>();String sql = "SELECT * FROM message";try{ ResultSet rs = this.executeQuery(sql, null);while(rs.next()){ Message msg = new Message();msg.setMessageid(rs.getInt("messageid"));msg.setContext(rs.getString("context")); msg.setLefttime(rs.getString("lefttime"));msg.setTitle(rs.getString("title"));msg.setWholeft(rs.getString("wholeft"));msglist.add(msg);}}catch(SQLException e){e.printStackTrace();}finally{this.closeAll();}return msglist;}public Message getMsgById(String id){Message msg = null;String sql = "SELECT * FROM message WHERE messageid = ?";try{ResultSet rs = this.executeQuery(sql, new String[]{id});if(rs.next()){msg = new Message();msg.setContext(rs.getString("context")); msg.setLefttime(rs.getString("lefttime"));msg.setMessageid(rs.getInt("messageid"));msg.setTitle(rs.getString("title"));msg.setWholeft(rs.getString("wholeft"));}}catch(SQLException e){e.printStackTrace();}return msg;} /*** 添加留言* @param msg* @return*/public boolean addMsg(Message msg){boolean r = false;String sql = "INSERT INTO message(title,context,wholeft,lefttime)VALUES(?,?,?,?) ";try{int num = this.executeUpdate(sql, new String[]{msg.getTitle(),msg.getContext(),msg.getWholeft(),msg.getLefttime()});if(num > 0){r = true;}}catch(Exception e){e.printStackTrace();}finally{this.closeAll();} return r;}/*** 修改留言信息* @param msg* @return*/public boolean editMsg(Message msg){boolean r = false;String sql = "UPDATE message SET context = ?,title =?,lefttime = ?,wholeft=? WHERE messageid ="+msg.getMessageid();try{int num = this.executeUpdate(sql,new String[]{msg.getContext(), msg.getTitle(), msg.getLefttime(), msg.getWholeft()});System.out.println("num:"+num);if(num > 0){r = true;}}catch(Exception e){ e.printStackTrace();}return r; }/*** 根据消息Id删除留言* @param id* @return*/public boolean delMsg(int id){boolean r = false;String sql = "DELETE FROM message WHERE messageid = ?";try{int num = this.executeUpdate(sql, new String[]{""+id});if(num > 0){r = true;}}catch(Exception e){e.printStackTrace();}return r; }
}
⑥.回复Reply类，代码如下：
Reply.Java
package com.szx.jnmc;public class Reply {private String context;private int messageid;public int getMessageid() {return messageid;}public void setMessageid(int messageid) {this.messageid = messageid;}public String getContext() {return context;}public void setContext(String context) {this.context = context;}
}
⑦.Reply的数据操作对象类，代码如下:
ReplyDao.Java
package com.szx.jnmc;import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;public class ReplyDao extends DBOper{/*** 获取所有留言* @return*/public List<Reply> getAllReply(){Reply reply = null;List<Reply>replylist = new ArrayList<Reply>();String sql = "SELECT * FROM reply";try{ResultSet rs = this.executeQuery(sql, null);while(rs.next()){reply = new Reply();reply.setContext(rs.getString("context")); replylist.add(reply);}}catch(SQLException e){e.printStackTrace();}finally{this.closeAll();}return replylist; }/*** 添加回复* @param reply* @return*/public boolean addReply(Reply reply){boolean r = false;String sql = "INSERT INTO reply(context,messageid)VALUES(?,?)";try{int num = this.executeUpdate(sql, new String[]{reply.getContext(),""+reply.getMessageid()});if(num > 0){r = true;}}catch(Exception e){e.printStackTrace();}finally{this.closeAll();}return r;}
}
第二步到此结束，这一步主要是对数据的封装和连接数据库。
第三步：
①.显示用户列表
userlist.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%><%@page import = "java.util.List" %><%@page import = "java.util.ArrayList" %><%@page import = "com.szx.jnmc.User" %><%@page import = "com.szx.jnmc.UserDao" %><%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!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=GBK">
<title>留言板</title>
</head>
<body>
<%request.setCharacterEncoding("GBK");response.setContentType("text/html;char=gbk");ServletContext ctx = request.getServletContext();String server = ctx.getInitParameter("server");String dbname = ctx.getInitParameter("dbname");String dbuser = ctx.getInitParameter("dbuser");String dbpwd = ctx.getInitParameter("dbpwd");List<User> userlist = new ArrayList<User>();UserDao dao = new UserDao();try{dao.getConn(server,dbname,dbuser,dbpwd); }catch(Exception e){e.printStackTrace();} userlist = dao.getAllUser(); pageContext.setAttribute("userlist", userlist);
%> <div class="list_div" style="height: 87%"><table border="1" align="center" cellspacing="0" class="list_table"id="senfe" style='width: 50%'><thead><tr><th width="5%"><span style="font-weight: 10">序号</span></th><th width="5%"><span style="font-weight: 10">用户名</span></th><th width="5%"><span style="font-weight: 10">操作</span></th> </tr></thead><tbody> <c:forEach var="user" items="${userlist}" varStatus="status"><tr> <td align="center">${status.count }</td><td align="center">${user.username}</td> <td align="center"><a
href="addmsg.jsp?username=${user.username}">留言</a></td> </tr> </c:forEach></tbody></table></div>
</body>
</html>效果如图
②.在用户列表里我们点击“留言”就可以对用户留言，页面将跳转到留言页面，如下：
addmsg.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%>
<!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=GBK">
<title>留言板</title>
</head>
<body>
<form method = "POST" action = "addOK.jsp">
留言人：<input type = "text" name = "wholeft"/>
留言主题：<input type = "text" name = "title"/>
留言内容：<input type = "text" name = "context"/>
<input type = "submit" value = "留言"/>
<input type = "reset" value = "重置"/>
</form>
</body>
</html>效果如图：
③.留言页面的数据处理，代码如下：
addOK.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%><%@page import = "com.szx.jnmc.Message" %><%@page import = "com.szx.jnmc.MsgDao" %><%@page import = "java.text.SimpleDateFormat" %><%@page import = "java.util.Date" %>
<!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=GBK">
<title>留言板</title>
</head>
<body>
<%request.setCharacterEncoding("GBK");response.setContentType("text/html;charset=GBK");String wholeft = request.getParameter("wholeft");String title = request.getParameter("title");String context = request.getParameter("context");ServletContext ctx = request.getServletContext();String server = ctx.getInitParameter("server");String dbname = ctx.getInitParameter("dbname");String dbuser = ctx.getInitParameter("dbuser");String dbpwd = ctx.getInitParameter("dbpwd");SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");Date curtime = new Date();String lefttime = sdf.format(curtime);Message msg = new Message();msg.setContext(context);msg.setLefttime(lefttime);msg.setTitle(title);msg.setWholeft(wholeft);MsgDao dao = new MsgDao();try{dao.getConn(server, dbname, dbuser, dbpwd);if(dao.addMsg(msg)){out.println("留言成功！");out.println("<br><a href = 'showmsg.jsp'>查看留言</a></br>");}else{out.println("留言失败！");}}catch(ClassNotFoundException e){e.printStackTrace();}
%>
</body>
</html>效果如图：
④.点击“查看留言”，将跳转到showmsg.jsp页面，代码如下：
showmsg.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%><%@page import = "java.util.List" %><%@page import = "java.util.ArrayList" %><%@page import = "com.szx.jnmc.MsgDao" %><%@page import = "com.szx.jnmc.Message" %><%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!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=GBK">
<title>留言板</title>
</head>
<body>
<%request.setCharacterEncoding("GBK");response.setContentType("text/html;charset=GBK");ServletContext ctx = request.getServletContext();String server = ctx.getInitParameter("server");String dbname = ctx.getInitParameter("dbname");String dbuser = ctx.getInitParameter("dbuser");String dbpwd = ctx.getInitParameter("dbpwd");MsgDao dao = new MsgDao(); List<Message> msglist = new ArrayList<Message>();try{dao.getConn(server,dbname,dbuser,dbpwd); }catch(Exception e){e.printStackTrace();}msglist = dao.getAllMsg();if(msglist!=null){application.setAttribute("msglist",msglist);}
%>
<div class="list_div" style="height: 87%"><table border="1" align="center" cellspacing="0" class="list_table"id="senfe" style='width: 80%'><thead><tr><th width="10%"height="30"><span style="font-weight: 10">留言序号</span></th><th width="10%"height="30"><span style="font-weight: 10">留言ID</span></th><th width="5%"height="30"><span style="font-weight: 10">留言人</span></th><th width="10%"height="30"><span style="font-weight: 10">主题</span></th> <th width="25%"height="30"><span style="font-weight: 10">留言内容</span></th> <th width="20%"height="30"><span style="font-weight: 10">操作</span></th> </tr></thead><tbody> <c:forEach var="msg" items="${msglist}" varStatus="status"><tr> <td align="center">${status.count }</td><td align="center">${msg.messageid}</td> <td align="center">${msg.wholeft}</td> <td align="center">${msg.title}</td> <td align="center">${msg.context}</td> <td align="center"><a href="reply.jsp?messageid=${msg.messageid}">回复</a><a href="editmsg.jsp?messageid=${msg.messageid}">编辑</a><a href="delmsg.jsp?messageid=${msg.messageid}">删除</a> </td> </tr> </c:forEach> </tbody></table></div>
</body>
</html>效果如图：
⑤.点击页面中的“回复”将跳转到reply.jsp，代码如下：
reply.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%><%@page import="com.szx.jnmc.Reply" %><%@page import="com.szx.jnmc.ReplyDao" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GBK">
<title>回复页面</title>
</head>
<body>
<%String messageid = request.getParameter("messageid"); if(messageid != null || messageid.equals("")){pageContext.setAttribute("messageid", messageid);}
%>
<form method = "POST" action = "replydo.jsp">
内容：<input type = "text" name = "context">
<input type = "hidden" name = "id" value="${messageid }">
<input type = "submit" value = "提交">
<input type = "reset" value ="重置">
</form>
</body>
</html>效果如图：
⑥.输入回复数据，点击提交转到回复结果replydo.jsp页面，代码如下：
replydo.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%><%@page import="com.szx.jnmc.Reply" %><%@page import="com.szx.jnmc.ReplyDao" %>
<!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=GBK">
<title>回复留言</title>
</head>
<body>
<%request.setCharacterEncoding("GBK");response.setContentType("text/html;charset=GBK");String messageid = request.getParameter("id");String context = request.getParameter("context"); ServletContext ctx = request.getServletContext();String server = ctx.getInitParameter("server");String dbname = ctx.getInitParameter("dbname");String dbuser = ctx.getInitParameter("dbuser");String dbpwd = ctx.getInitParameter("dbpwd");Reply reply = new Reply();ReplyDao dao = new ReplyDao();reply.setContext(context);try{dao.getConn(server, dbname, dbuser, dbpwd);if(dao.addReply(reply)){out.println("回复成功！");out.println("<br><a href = 'showmsg.jsp'>返回留言列表</a></br>");}else{out.println("回复失败！");out.println("<br><a href = 'replydo.jsp'>重新回复</a></br>");}}catch(Exception e){e.printStackTrace();}
%>
</body>
</html>效果如图：
⑦.点击返回留言列表，转到留言列表showmsg.jsp页面，进行编辑，代码如下：
editmsg.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%><%@page import = "com.szx.jnmc.MsgDao" %><%@page import = "com.szx.jnmc.Message" %>
<!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=GBK">
<title>修改留言</title>
</head>
<body>
<%String messageid = request.getParameter("messageid");request.setCharacterEncoding("GBK");response.setContentType("text/html;charset=GBK");ServletContext ctx = request.getServletContext();String server = ctx.getInitParameter("server");String dbname = ctx.getInitParameter("dbname");String dbuser = ctx.getInitParameter("dbuser");String dbpwd = ctx.getInitParameter("dbpwd");MsgDao dao = new MsgDao();try{dao.getConn(server, dbname, dbuser, dbpwd);Message msg = dao.getMsgById(messageid);if(msg != null){pageContext.setAttribute("msg", msg);}}catch(Exception e){e.printStackTrace();}
%>
<form method = "POST" action = "editmsgdo.jsp">
<table><tr><td>主题： <input type = "text" name = "title" value ="${msg.title}"></td></tr><tr><td>内容： <input type = "text" name = "context" value ="${msg.context}"></td></tr><tr><%-- <input type = "text" name = "lefttime" value ="${msg.lefttime}"> --%><td>日期： <span>${msg.lefttime }</span></td> </tr><%-- <input type = "text" name = "wholeft" value ="${msg.wholeft}"readonly="readonly"> --%><tr><td>留言人：<span>${msg.wholeft}</span></td></tr><%-- <input type ="text" name = "messageid" value = "${msg.messageid }" readonly="readonly"> --%><tr><td>留言id：<input type ="text" name = "messageid" value = "${msg.messageid }" readonly="readonly"></td> </tr><tr><td><td><input type = "submit" value = "提交"></td> <td><input type = "reset" value = "重置"></td></tr></table>
</form>
</body>
</html>效果如图：
⑧.点击提交，跳转到 编辑结果页面editmsgdo.jsp，代码如下：
editmsgdo.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%><%@page import = "com.szx.jnmc.MsgDao" %><%@page import = "com.szx.jnmc.Message" %>
<!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=GBK">
<title>修改留言</title>
</head>
<body>
<%request.setCharacterEncoding("GBK");response.setContentType("text/html;charset=GBK");String title = request.getParameter("title");String context = request.getParameter("context");String messageid = request.getParameter("messageid");String lefttime = request.getParameter("lefttime");String wholeft = request.getParameter("wholeft"); ServletContext ctx = request.getServletContext();String server = ctx.getInitParameter("server");String dbname = ctx.getInitParameter("dbname");String dbuser = ctx.getInitParameter("dbuser");String dbpwd = ctx.getInitParameter("dbpwd"); MsgDao dao = new MsgDao(); Message msg = new Message();msg.setContext(context);msg.setTitle(title);msg.setLefttime(lefttime);msg.setWholeft(wholeft);try{dao.getConn(server,dbname,dbuser,dbpwd);if(dao.editMsg(msg)){out.println("修改成功");out.println("<br><a href = 'showmsg.jsp'>返回留言列表</a></br>");}else{out.println("修改失败");out.println("<br><a href = 'editmsgdo.jsp'>重新修改</a></br>");}}catch(Exception e){e.printStackTrace();}
%>
</body>
</html>效果如图：
⑨.点击“返回留言列表 ”回到留言列表页面，点击删除则直接删除留言，代码如下：
delmsg.jsp
<%@ page language="java" contentType="text/html; charset=GBK"pageEncoding="GBK"%><%@page import = "com.szx.jnmc.MsgDao" %><%@page import = "com.szx.jnmc.Message" %>
<!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=GBK">
<title>留言板</title>
</head>
<body>
<%request.setCharacterEncoding("GBK");response.setContentType("text/html;charset=GBK");ServletContext ctx = request.getServletContext();String server = ctx.getInitParameter("server");String dbname = ctx.getInitParameter("dbname");String dbuser = ctx.getInitParameter("dbuser");String dbpwd = ctx.getInitParameter("dbpwd");MsgDao dao = new MsgDao();try{String messageid = request.getParameter("messageid");dao.getConn(server,dbname,dbuser,dbpwd);if(dao.delMsg(Integer.parseInt(messageid))){out.println("删除成功");response.sendRedirect("showmsg.jsp");}else{out.println("删除失败");}}catch(Exception e){e.printStackTrace();}
%>
</body>
</html>数据表的创建SQL语句：
user表：
CREATE TABLE `user` (`username` varchar(255) NOT NULL,`userpass` varchar(255) NOT NULL,`phone` varchar(255) DEFAULT NULL,`email` varchar(255) DEFAULT NULL,`userid` int(11) NOT NULL AUTO_INCREMENT,PRIMARY KEY (`userid`)
) ENGINE=InnoDB AUTO_INCREMENT=32 DEFAULT CHARSET=utf8;message表：
CREATE TABLE `message` (`messageid` int(11) NOT NULL AUTO_INCREMENT,`title` varchar(255) DEFAULT NULL,`context` varchar(255) DEFAULT NULL,`wholeft` varchar(255) DEFAULT NULL,`lefttime` datetime DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,PRIMARY KEY (`messageid`)
) ENGINE=InnoDB AUTO_INCREMENT=25 DEFAULT CHARSET=utf8;reply表：
CREATE TABLE `reply` (`context` varchar(255) DEFAULT NULL,`messageid` int(11) NOT NULL AUTO_INCREMENT,PRIMARY KEY (`messageid`)
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=utf8;
