JSP用串連池連資料庫的問題

js|資料|資料庫|問題  

各位高手麻煩幫我看下面這三個檔案(一個jsp,兩個.java),我在IE輸入地址時,提示如下錯誤(代碼應該沒有錯,不知是不是設定的問題),望高手指教,不勝感激:

D:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\shopping\index_jsp.java:44: package mybean does not exist
      mybean.DBConnManager connManager = null;
            ^



An error occurred at line: 2 in the jsp file: /shopping/index.jsp

Generated servlet error:
D:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\shopping\index_jsp.java:46: package mybean does not exist
        connManager = (mybean.DBConnManager) pageContext.getAttribute("connManager", PageContext.APPLICATION_SCOPE);
                             ^



An error occurred at line: 2 in the jsp file: /shopping/index.jsp

Generated servlet error:
D:\Program Files\Apache Group\Tomcat 4.1\work\Standalone\localhost\_\shopping\index_jsp.java:49: package mybean does not exist
            connManager = (mybean.DBConnManager) java.beans.Beans.instantiate(this.getClass().getClassLoader(), "mybean.DBConnManager");
                                 ^

//下面這兩個是串連池,下面兩個檔案都放在一個mybean的包裡.

package mybean;
import java.sql.*;
import java.util.*;

public class DBConnPool {
  //正在使用串連的數量
  private int using;
  //目前可用的串連數,即空閑串連
  private Vector connections=new Vector();
  //最大串連數
  private int maxconn;
  //串連池名
  private String poolname;
  //資料庫標識
  private String dbid;
  //驅動程式名
  private String drivername;
  //資料庫帳號
  private String username;
  //資料庫密碼
  private String passwd;

  public DBConnPool(String poolname,String dbid,String drivername,
                    String username,String passwd,int maxconn){
    this.poolname=poolname;
    this.drivername=drivername;
    this.dbid =dbid;
    this.username =username;
    this.passwd=passwd;
    this.maxconn=maxconn;
  }

  /*將空閑串連返回給串連池*/
  public synchronized void returnConnection(Connection conn){
    //將指定串連加到向量末尾
    connections.addElement(conn);
    //串連使用者減一
    using--;
  }

  /*從串連池得到一個串連*/
  public synchronized Connection getConnection(){
    Connection conn = null; //Connection是一個類,
    //connections是一個向量,用於儲存連線物件,它所儲存是的所有空閑狀態的可用串連
    if (connections.size() > 0) {

      //擷取串連列表的第一個串連
      conn = (Connection) connections.elementAt(0);
      connections.removeElementAt(0);//獲得一個串連,並將此串連從隊列中刪除.

      //如果此串連已關閉,剛繼續擷取,
      try {
        if (conn.isClosed())
          conn = getConnection();
      }
      catch (Exception e) {
        e.printStackTrace();
      }
    }
      //如果實際使用的串連數小於最大串連數即有可用串連),就新增加一個串連
    else if (maxconn == 0 || using < maxconn){
      //如此時無可用串連(maxconn == 0)且串連數又未達到上限(using < maxconn)),就建立一個新串連
        conn=newConnection();
      }
      //如果串連數已達到上限就返回null 指標
      if (conn!=null){
        using++;
      }
    return conn;
  }

/*建立新的串連*/
  public Connection newConnection(){
    Connection conn=null;
    try{
      //載入驅動
      Class.forName(drivername);
      conn=DriverManager.getConnection(dbid,username,passwd);
    }catch(Exception e){
      e.printStackTrace();
      return null;
    }
    return conn;
  }

 /*關閉所有串連*/
 public synchronized void closeConn(){
   Enumeration allConnections=connections.elements();
   while (allConnections.hasMoreElements()){
     Connection conn=(Connection) allConnections.nextElement();
     try{
       conn.close();
     }catch(SQLException e){
       e.printStackTrace();
     }
   }
   connections.removeAllElements();
 }
}

package mybean;
import java.sql.*;
import java.util.*;

public class DBConnManager {
  //串連池名列表
  private Vector poolnames =new Vector();
  //驅動程式名列表
  private Vector drivernames=new Vector();
  //資料庫識別欄位表
  private Vector dbids=new Vector();
  //使用者名稱列表
  private Vector usernames=new Vector();
  //使用者密碼列表
  private Vector passwds=new Vector();
  //最大串連數列表
  private Vector maxconns=new Vector();
  //串連池隊列
  private Hashtable connPools=new Hashtable();

  public DBConnManager() {
    //添加Access資料庫的串連資訊
    poolnames.addElement("access");
    drivernames.addElement("sun.jdbc.odbc.JdbcOdbcDriver");
    dbids.addElement("jdbc:odbc:shopping");
    usernames.addElement("");
    passwds.addElement("");
    maxconns.addElement("5");

    //添加SQL Server2000資料庫的串連資訊
    poolnames.addElement("sqlserver2000");
    drivernames.addElement("com.microsoft.jdbc.sqlserver.SQLServerDriver");
    dbids.addElement("jdbc:microsoft:sqlserver://localhost:1433;DatabserName=shopping");
    usernames.addElement("");
    passwds.addElement("");
    maxconns.addElement("5");

    //串連Mysql資料庫資訊
    poolnames.addElement("mysql");
    drivernames.addElement("org.gjt.mm.mysql.Driver");
    dbids.addElement("jdbc:mysql://localhost/shopping");
    usernames.addElement("");
    passwds.addElement("");
    maxconns.addElement("5");

    //串連Oracle8i/9i資料庫
    poolnames.addElement("oracle");
    drivernames.addElement("oracle.jdbc.driver.OracleDriver");
    dbids.addElement("jdbc:oracle:thin:@localhost:1521:shopping");
    usernames.addElement("");
    passwds.addElement("");
    maxconns.addElement("5");

    //建立串連池
    createPools();
  }

  /*將串連返回給由指定的串連池*/
  public void returnConnection(String name,Connection conn){
    DBConnPool pool=(DBConnPool) connPools.get(name);
    if (pool!=null)
    {
      pool.returnConnection(conn);
    }
  }

  /*得到一個指定串連池中的串連*/
  public Connection getConnection(String name){
    DBConnPool pool=(DBConnPool) connPools.get(name);
    if (pool!=null)
    {
      return pool.getConnection();
    }
    return null;
  }

  /*關閉所有串連*/
  public synchronized void closeConns(){
    Enumeration allPools=connPools.elements();
    while (allPools.hasMoreElements()){
      DBConnPool pool=(DBConnPool) allPools.nextElement();
      pool.closeConn();
    }
  }

  /*建立串連池*/
  private void createPools(){
    for (int i=0;i<poolnames.size();i++)
    {
      String poolname=poolnames.elementAt(i).toString();
      String drivername=drivernames.elementAt(i).toString();
      String dbid=dbids.elementAt(i).toString();
      String username=usernames.elementAt(i).toString();
      String passwd=passwds.elementAt(i).toString();
      int maxconn=0;
      try{
        maxconn=Integer.parseInt(maxconns.elementAt(i).toString());
      }catch (NumberFormatException e){
        e.printStackTrace();
      }
      DBConnPool pool=new DBConnPool(poolname,drivername,dbid,username,
                                     passwd,maxconn);
      connPools.put(poolname,pool);
    }
  }
}

下面這個是首頁面.JSP檔案

<%@ page contentType="text/html; charset=GBK" %>
<%@ page import ="java.sql.*" %>
<jsp:useBean id="connManager" scope="application" class="mybean.DBConnManager" />
<html>
<head>
<title>
購物商城首頁
</title>
</head>
<body bgcolor="#B0C4DE">
<center><h1>歡迎訪問本購物商城</h1></center>
<%
//Connection connA=connManager.getConnection("access");
Connection connS=connManager.getConnection("sqlserver2000");
if (connS==null)
{
%>
  資料庫正忙,請稍後再訪問
<%
}
//Statement stmtA=connA.createStatement();
Statement stmtS=connS.createStatement();
%>

<%
String sql="select * from userinfo";
ResultSet rs=stmtS.executeQuery(sql);
while (rs.next())
{
%>
<tr>
<td><%=rs.getString("username")%></td>
<td><%=rs.getString("userpass")%></td>
</tr>
<%
}
rs.close();
stmtS.close();
connManager.returnConnection("sqlserver2000",connS);
%>

</body>
</html>