一个applet servlet之间通过序列化对象通讯的例子

				package espc;								import java.io.*;				import java.sql.*;				import java.util.Properties;								public class DbConnection				{								    Connection conn=null;				    Statement stmt=null;				    ResultSet rset=null;				    //构造方法				    public DbConnection()				    {								    }								    public boolean openConnection()				    {				    //-----------------------------------------------------------------				    //装载数据库的Property文件：其中包括数据库驱动，数据库URL，即用户ID和密码				    //-----------------------------------------------------------------				      Properties prop = new Properties();				        try				        {				            InputStream is = getClass().getResourceAsStream("Db.properties");				            prop.load(is);				            if(is != null)				             is.close();				        }				        catch(IOException e)				        {				            System.out.println("[DbConnection]打开文件时出现错误！");				        }				        //-----------------------------------------------------------				        //从property文件中读出数据库Property				        //-----------------------------------------------------------				        String jdbc = prop.getProperty("drivers");				        String url = prop.getProperty("url");				        String user = prop.getProperty("user");				        String password = prop.getProperty("password");				        //-----------------------------------------------------------				        //将输入的property输出到Debugging				        //-----------------------------------------------------------				        System.out.println(String.valueOf(String.valueOf((new StringBuffer("jdbc＝[")).append(jdbc).append("]"))));				        System.out.println(String.valueOf(String.valueOf((new StringBuffer("url＝[")).append(url).append("]"))));				        System.out.println(String.valueOf(String.valueOf((new StringBuffer("user＝[")).append(user).append("]"))));				        System.out.println(String.valueOf(String.valueOf((new StringBuffer("password＝[")).append(password).append("]"))));				        //-----------------------------------------------------------				        //加载jdbc驱动				        //-----------------------------------------------------------				        try				        {				            Class.forName(jdbc);				            System.out.println("驱动程序加载成功！");				        }				        catch(ClassNotFoundException e)				        {				            System.out.println("JDBC登陆过程中出现错误".concat(String.valueOf(String.valueOf(e.getMessage()))));				            boolean flag = false;				            return flag;				        }				        //-----------------------------------------------------------				        //打开数据库connection				        //-----------------------------------------------------------				        try				        {				            conn = DriverManager.getConnection(url, user, password);				            System.out.println("数据库连接成功！！");				        }				        catch(SQLException e)				        {				            System.out.println("数据库连接过程中出现错误".concat(String.valueOf(String.valueOf(e.getMessage()))));				            boolean flag1 = false;				            return flag1;				        }				        return true;				    }								    public ResultSet executeQuery(String query)				        throws SQLException				    {				        stmt = conn.createStatement(1004, 1007);				        rset = stmt.executeQuery(query);				        return rset;				    }								    public void executeUpdate(String query)				        throws SQLException				    {				        stmt = conn.createStatement(1004, 1008);				        stmt.executeUpdate(query);				        if(stmt != null)				            stmt.close();				    }								    public void close()				        throws SQLException				    {				        if(conn != null)				            conn.close();				        if(rset != null)				            rset.close();				        if(stmt != null)				            stmt.close();				    }								    protected void finalize()				        throws Throwable				    {				        close();				    }				}