messagebean.java

Internet 开发技术分章节代码和自己完成的课程设计全代码（在zuoye文件夹里）使用时

package message;
import java.sql.*;  //引入java.sql包
import java.util.*;
public class  MessageBean {
	private Connection con;
	MessageData msg;
	//获得数据库连接。
	public MessageBean()
	{
		   String JDriver = "sun.jdbc.odbc.JdbcOdbcDriver"; //声JDBC驱动程序对象
		   String conURL="jdbc:odbc:message"; //定义JDBC的URL对象
		   try {
		     Class.forName(JDriver); //加载JDBC-ODBC桥驱动程序
		     con=DriverManager.getConnection(conURL); //连接数据库URL
		     }
		   catch(Exception e)
		     {  System.err.println(e.getMessage()); }
	}
  //	设置成员变量的值
	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,null);
			else stm.setString(3,em);	
			stm.setString(4,c); 					
			try 
			{
				stm.executeQuery();
			} 
			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 getAllMessage()throws Exception
	{
		Collection ret=new ArrayList();
		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;
	}
}