利用java编写一个留言板功能

java 留言板 ava 2023-05-31 16:05:45 654人浏览安东尼

摘要

本篇文章为大家展示了利用java编写一个留言板功能，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。JSP+JavaBean的留言板技术<span >Messages.html <HT

本篇文章为大家展示了利用java编写一个留言板功能，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。

JSP+JavaBean的留言板技术

<span >Messages.html <HTML></span><span ><HEAD> <TITLE> message board </TITLE></HEAD> <BODY> <center>留言板</center> <FORM action="addMessage.jsp" >  <TABLE border=1 align="center">  <TR><TD>姓名：</TD><TD><input type="text" name="name" size=25>   </TD></TR>  <TR><TD>E-mail：</TD>   <TD><input type="text" name="email" size=25></TD></TR>  <TR><TD>主题：</TD>   <TD><input type="text" name="title" size=25></TD></TR>   <TR><TD>留言：</TD>   <TD><textarea name="content" rows=7 cols=25></textarea>   </TD></TR>   <TR><TD colspan=3> <TABLE align="center" width="100%" cellspacing="0" cellpadding="0" >   <TR>    <TD align="center"><input type="submit" value="提交留言"></TD>   <TD align="center">   <a href="viewMessages.jsp" rel="external nofollow" ><font size=2>查看留言</font></a></TD>   <TD align="center"><input type="reset" value="重新填写"></TD>   </TR></TABLE></TD> </TR></TABLE></FORM></BODY></HTML></span>&#63;<span >MessageData.java package message; public class MessageData   { private String name,email,title,content;   //setter或者getter方法   public void setName(String name){this.name=name;}   public void setEmail(String email){ this.email=email;}   public void setTitle(String title){ this.title=title;}   public void setContent(String content){this.content=content;}   public String getName(){ return this.name;}   public String getContent(){ return this.content;}   public String getTitle(){ return this.title;}   public String getEmail(){ return this.email;}}</span>&#63;<span >viewMessages.jsp   <%@ page contentType="text/html; charset=GBK" import="message.MessageData" %> <%@ page import="java.util.*"%> <jsp:useBean id="myBean" class="message.MessageBean" scope="page"/> <HTML><HEAD><TITLE> show the message in the table </TITLE></HEAD> <BODY><p align="center">所有留言</p>  <TABLE align="center" width="80%" border=1 >  <%     int message_count=0;   Collection <MessageData> messages=myBean.getAllMessage();   Iterator <MessageData> it=messages.iterator();   while(it.hasNext()){ MessageData mg=(MessageData)it.next();    %>   <tr>     <td width="20%">留言人:</td>     <td width="23%"><%=mg.getName()%></td>     <td width="58%" align="center"><% out.println(   "<a href=mailto:"+mg.getEmail()+">"+mg.getEmail()+"</a>"); %></td></tr>   <tr>     <td width="20%">主题:</td>     <td colspan="3"><%=mg.getTitle()%></td>   </tr>   <tr>     <td width="20%">内容:</td>     <td colspan="3"><%=mg.getContent()%></td>   </tr>   <% message_count++;  }    %>  </Table> <p align="center"><a href="Messages.html" rel="external nofollow" >我要留言</a></p> </body></html></span>&#63;<span >addMessage.jsp <%@ page language="java" contentType="text/html; charset=GBK"  pageEncoding="GBK"%> <jsp:useBean id="Mdata" class="message.MessageData" scope="page">   <jsp:setProperty name="Mdata" property="*"/></jsp:useBean> <jsp:useBean id="myBean" class="message.MessageBean" scope="page"/> <HTML><HEAD><TITLE> message into table </TITLE></HEAD> <BODY> <% try { myBean.setMessage(Mdata);  myBean.addMessage(); }   catch(Exception e) { e.printStackTrace();} %> <jsp:forward page="viewMessages.jsp" /> </body></html></span>&#63;<span >MessageData.java package message; public class MessageData   { private String name,email,title,content;   //setter或者getter方法   public void setName(String name){this.name=name;}   public void setEmail(String email){ this.email=email;}   public void setTitle(String title){ this.title=title;}   public void setContent(String content){this.content=content;}   public String getName(){ return this.name;}   public String getContent(){ return this.content;}   public String getTitle(){ return this.title;}   public String getEmail(){ return this.email;}}</span>&#63;<span >MessageBean.java package message; import java.sql.*;  //引入java.sql包 import java.util.*; public class MessageBean {   private Connection con;   MessageData msg;   public MessageBean()   { String JDriver="com.mysql.jdbc.Driver"; //定义驱动程序对象     String userName="root"; //定义数据库用户名     String userPasswd=""; //定义数据库存取密码     String dbName="message"; //定义数据库名     String conURL="jdbc:Mysql://localhost:3306/"+dbName;    try{Class.forName(JDriver).newInstance(); //加载JDBC驱动程序   con=DriverManager.getConnection(conURL,userName,userPasswd);    //连接数据库     }   catch(Exception e){System.err.println(e.getMessage());}   }   public void setMessage(MessageData msg) {this.msg=msg;}   //  添加一条留言消息   public void addMessage()throws Exception   { try{ byte b1[]=msg.getTitle().getBytes("ISO-8859-1");       String ti=new String(b1);       byte b2[]=msg.getName().getBytes("ISO-8859-1");       String na=new String(b2);       byte b3[]=msg.getEmail().getBytes("ISO-8859-1");       String em=new String(b3);       byte b4[]=msg.getContent().getBytes("ISO-8859-1");       String c=new String(b4);       PreparedStatement stm=con.prepareStatement(   "insert into messagetable values(&#63;,&#63;,&#63;,&#63;)");       stm.setString(1,ti); stm.setString(2,na);       if((msg.getEmail()).length()==0)stm.setString(3,"");       else stm.setString(3,em);         stm.setString(4,c);       try {stm.execute();  stm.close(); }        catch(Exception e) { }             con.close(); //关闭数据库连接     }     catch(Exception e){ e.printStackTrace(); throw e;}   }   //  获得所有留言消息，并返回结果到JSP页面  public Collection<MessageData> getAllMessage()throws Exception   { Collection<MessageData> ret=new ArrayList<MessageData>();   try{ Statement stm=con.createStatement();      ResultSet result=stm.executeQuery(   "select count(*) from messagetable");         int message_count=0;     if(result.next()){ message_count=result.getInt(1);         result.close(); }     if(message_count>0)     { result=stm.executeQuery("select * from messagetable ");    while(result.next())   { String title=result.getString("title");      String name=result.getString("name");      String email=result.getString("email");      String content=result.getString("content");      MessageData message=new MessageData();      message.setTitle(title); message.setName(name);   message.setEmail(email); message.setContent(content);   ret.add(message);                 }     result.close();   stm.close();    }        con.close();       }   catch(Exception e)    { e.printStackTrace(); throw e; }   return ret;   } }</span>