各位高手麻烦帮我看下面这三个文件(一个jsp,两个.java),我在IE输入地址时,提示如下错误(代码应该没有错,不知是不是设置的问题),望高手指教,不胜感激: 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"); ^ //下面这两个是连接池,下面两个文件都放在一个mybean的包里. package mybean; import java.sql.*; import java.util.*; public class DBConnPool { //正在使用连接的数量 private int using; //目前可用的连接数,即空闲连接 private Vector connections=new Vector(); //最大连接数 private int maxconn; //连接池名 private String poolname; //数据库标识 private String dbid; //驱动程序名 private String drivername; //数据库帐号 private String username; //数据库密码 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; } /*将空闲连接返回给连接池*/ public synchronized void returnConnection(Connection conn){ //将指定连接加到向量末尾 connections.addElement(conn); //连接用户减一 using--; } /*从连接池得到一个连接*/ public synchronized Connection getConnection(){ Connection conn = null; //Connection是一个类, //connections是一个向量,用于存储连接对象,它所存储是的所有空闲状态的可用连接 if (connections.size() > 0) { //获取连接列表的第一个连接 conn = (Connection) connections.elementAt(0); connections.removeElementAt(0);//获得一个连接,并将此连接从队列中删除. //如果此连接已关闭,刚继续获取, try { if (conn.isClosed()) conn = getConnection(); } catch (Exception e) { e.printStackTrace(); } } //如果实际使用的连接数小于最大连接数即有可用连接),就新增加一个连接 else if (maxconn == 0 || using < maxconn){ //如此时无可用连接(maxconn == 0)且连接数又未达到上限(using < maxconn)),就创建一个新连接 conn=newConnection(); } //如果连接数已达到上限就返回空指针 if (conn!=null){ using++; } return conn; } /*创建新的连接*/ public Connection newConnection(){ Connection conn=null; try{ //加载驱动 Class.forName(drivername); conn=DriverManager.getConnection(dbid,username,passwd); }catch(Exception e){ e.printStackTrace(); return null; } return conn; } /*关闭所有连接*/ 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 { //连接池名列表 private Vector poolnames =new Vector(); //驱动程序名列表 private Vector drivernames=new Vector(); //数据库标识列表 private Vector dbids=new Vector(); //用户名列表 private Vector usernames=new Vector(); //用户密码列表 private Vector passwds=new Vector(); //最大连接数列表 private Vector maxconns=new Vector(); //连接池队列 private Hashtable connPools=new Hashtable(); public DBConnManager() { //添加Access数据库的连接信息 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数据库的连接信息 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"); //连接Mysql数据库信息 poolnames.addElement("mysql"); drivernames.addElement("org.gjt.mm.mysql.Driver"); dbids.addElement("jdbc:mysql://localhost/shopping"); usernames.addElement(""); passwds.addElement(""); maxconns.addElement("5"); //连接Oracle8i/9i数据库 poolnames.addElement("oracle"); drivernames.addElement("oracle.jdbc.driver.OracleDriver"); dbids.addElement("jdbc:oracle:thin:@localhost:1521:shopping"); usernames.addElement(""); passwds.addElement(""); maxconns.addElement("5"); //创建连接池 createPools(); } /*将连接返回给由指定的连接池*/ public void returnConnection(String name,Connection conn){ DBConnPool pool=(DBConnPool) connPools.get(name); if (pool!=null) { pool.returnConnection(conn); } } /*得到一个指定连接池中的连接*/ public Connection getConnection(String name){ DBConnPool pool=(DBConnPool) connPools.get(name); if (pool!=null) { return pool.getConnection(); } return null; } /*关闭所有连接*/ public synchronized void closeConns(){ Enumeration allPools=connPools.elements(); while (allPools.hasMoreElements()){ DBConnPool pool=(DBConnPool) allPools.nextElement(); pool.closeConn(); } } /*创建连接池*/ private void createPools(){ for (int i=0;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); } } } 下面这个是主页面.JSP文件 <%@ page contentType="text/html; charset=GBK" %> <%@ page import ="java.sql.*" %> 购物商城首页 欢迎访问本购物商城<% //Connection connA=connManager.getConnection("access"); Connection connS=connManager.getConnection("sqlserver2000"); if (connS==null) { %> 数据库正忙,请稍后再访问 <% } //Statement stmtA=connA.createStatement(); Statement stmtS=connS.createStatement(); %> <% String sql="select * from userinfo"; ResultSet rs=stmtS.executeQuery(sql); while (rs.next()) { %> <%=rs.getString("username")%> | <%=rs.getString("userpass")%> | <% } rs.close(); stmtS.close(); connManager.returnConnection("sqlserver2000",connS); %> |
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