jsp+ javaBean+Mysql简易留言板

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="123456"; //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");//统计行数 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; } }