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java简单用户界面--实现java留言板功能

程序员文章站 2022-03-19 21:45:14
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JSP+JavaBean技术在我以前做过的一个留言板中用到,那是一次较为完整的开发,所以就拿这个学习吧!在这一次的实习作品中可能会用到,所以想起来复习一下了。

JSP+JavaBean的留言板技术

<span style="font-size:16px;">Messages.html  
<HTML></span><span style="font-size:16px;"><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"><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>
<span style="font-size:16px;">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>
<span style="font-size:16px;">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">我要留言</a></p>  
</body></html></span>
<span style="font-size:16px;">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>
<span style="font-size:16px;">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>
<span style="font-size:16px;">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(?,?,?,?)");  
            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>

功能简单的留言板,但是清楚的说明了JSP+JavaBean技术的运用,相信这一个例子可以帮助我们更清楚地掌握该技术的原理。

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