一个初学者的难题，请好心人看看
package hit;

import java.sql.*;
import java.util.*;

public class MessageBean
{
private Connection con;
MessageVO msg;

//????????????
public MessageBean()
{
String CLASSFORNAME="com.microsoft.jdbc.sqlserver.SQLServerDriver";
String SERVANDDB="jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=jspdev";
String USER="bn";
String PWD="bn"; 
try
{
//????????????
Class.forName(CLASSFORNAME);
con = DriverManager.getConnection(SERVANDDB,USER,PWD);
}
catch(Exception e)
{
e.printStackTrace();
}
}

//?????????
public void setMessage(MessageVO msg)
{
this.msg=msg;
}

//??????????
public void addMessage()throws Exception
{
try
{
PreparedStatement stm=con.prepareStatement("insert into message values(?,?,?,?,?)");
stm.setString(1,msg.getTitle());
stm.setString(2,msg.getName());
stm.setDate(3,new java.sql.Date(new java.util.Date().getTime()));
if((msg.getEmail()).length()==0)
stm.setString(5,null);
else stm.setString(5,msg.getEmail());
stm.setString(4,msg.getContent());
try 
{
stm.executeQuery();
} 
catch(Exception e) 
{
}

con.close();
}
catch(Exception e)
{
e.printStackTrace();
throw e;
}
}
//?????????????????????????JSP??档
public Collection<MessageVO> getMessage()throws Exception
{
Collection<MessageVO> ret=new ArrayList<MessageVO>();
try
{
Statement stm=con.createStatement();
ResultSet result=stm.executeQuery("select count(*) from message");
int message_count=0;
if(result.next())
{
message_count=result.getInt(1);
result.close();
}
if(message_count>0)
{
result=stm.executeQuery("select * from message order by time desc");

while(result.next())
{
String title=result.getString("title");
String name=result.getString("name");
String mail=result.getString("mail");
String content=result.getString("content");
java.sql.Date date=result.getDate("time");
MessageVO message=new MessageVO();
message.setName(name);
message.setTitle(title);
message.setContent(content);
message.setDate(date);
message.setEmail(mail);
ret.add(message);
}
result.close();
stm.close();
}

con.close();

}
catch(Exception e)
{
e.printStackTrace();
throw e;
}
return ret;
}
}


package hit;

public class MessageVO implements java.io.Serializable {
/**
* 
*/
private static final long serialVersionUID = 1L;
private String name,email,title,content;
private java.sql.Date date;
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