各位高手麻煩幫我看下面這三個文件(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,不知是不是設置的問題),望高手指教,不勝感激:
D:Program Filesapache GroupTomcat 4.1workStandalonelocalhost\_shoppingindex_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 Filesapache GroupTomcat 4.1workStandalonelocalhost\_shoppingindex_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 Filesapache GroupTomcat 4.1workStandalonelocalhost\_shoppingindex_JSP.Java:49: package mybean does not exist
connManager = (mybean.DBConnManager) Java.beans.Beans.instantiate(this.getClass().getClassLoader(), "mybean.DBConnManager");
^
//下面這兩個是連接池,下面兩個文件都放在一個mybean的包裡.
package mybean;
import Java.sql.*;
import Java.util.*;
public class DBConnPool {
//正在使用連接的數量
private int using;
//目前可用的連接數,即空閒連接
private Vector connections=new Vector();
//最大連接數
private int maxconn;
//連接池名
private String poolname;
//數據庫（數據庫培訓 數據庫認證 ）標識
private String dbid;
//驅動程序名
private String drivername;
//數據庫帳號
private String username;
//數據庫密碼
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;
}
/*將空閒連接返回給連接池*/
public synchronized void returnConnection(Connection conn){
//將指定連接加到向量末尾
connections.addElement(conn);
//連接用戶減一
using--;
}
/*從連接池得到一個連接*/
public synchronized Connection getConnection(){
Connection conn = null; //Connection是一個類,
//connections是一個向量,用於存儲連接對象,它所存儲是的所有空閒狀態的可用連接
if (connections.size() > 0) {
//獲取連接列表的第一個連接
conn = (Connection) connections.elementAt(0);
connections.removeElementAt(0);//獲得一個連接,並將此連接從隊列中刪除.
//如果此連接已關閉,剛繼續獲取,
try {
if (conn.isClosed())
conn = getConnection();
}
catch (Exception e) {
e.printStackTrace();
}
}
//如果實際使用的連接數小於最大連接數即有可用連接),就新增加一個連接
else if (maxconn == 0 || using < maxconn){
//如此時無可用連接(maxconn == 0)且連接數又未達到上限(using < maxconn)),就創建一個新連接
conn=newConnection();
}
//如果連接數已達到上限就返回空指針
if (conn!=null){
using++;
}
return conn;
}
/*創建新的連接*/
public Connection newConnection(){
Connection conn=null;
try{
//加載驅動
Class.forName(drivername);
conn=DriverManager.getConnection(dbid,username,passwd);
}catch(Exception e){
e.printStackTrace();
return null;
}
return conn;
}
/*關閉所有連接*/
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 {
//連接池名列表
private Vector poolnames =new Vector();
//驅動程序名列表
private Vector drivernames=new Vector();
//數據庫標識列表
private Vector dbids=new Vector();
//用戶名列表
private Vector usernames=new Vector();
//用戶密碼列表
private Vector passwds=new Vector();
//最大連接數列表
private Vector maxconns=new Vector();
//連接池隊列
private Hashtable connPools=new Hashtable();
public DBConnManager() {
//添加Access數據庫的連接信息
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數據庫的連接信息
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");
//連接MySQL數據庫信息
poolnames.addElement("MySQL");
drivernames.addElement("org.gjt.mm.MySQL.Driver");
dbids.addElement("jdbc:MySQL://localhost/shopping");
usernames.addElement("");
passwds.addElement("");
maxconns.addElement("5");
//連接Oracle8i/9i數據庫
poolnames.addElement("Oracle");
drivernames.addElement("oracle.jdbc.driver.OracleDriver");
dbids.addElement("jdbc:Oracle:thin:@localhost:1521:shopping");
usernames.addElement("");
passwds.addElement("");
maxconns.addElement("5");
//創建連接池
createPools();
}
/*將連接返回給由指定的連接池*/
public void returnConnection(String name,Connection conn){
DBConnPool pool=(DBConnPool) connPools.get(name);
if (pool!=null)
{
pool.returnConnection(conn);
}
}
/*得到一個指定連接池中的連接*/
public Connection getConnection(String name){
DBConnPool pool=(DBConnPool) connPools.get(name);
if (pool!=null)
{
return pool.getConnection();
}
return null;
}
/*關閉所有連接*/
public synchronized void closeConns(){
Enumeration allPools=connPools.elements();
while (allPools.hasMoreElements()){
DBConnPool pool=(DBConnPool) allPools.nextElement();
pool.closeConn();
}
}
/*創建連接池*/
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);
}
}
}
下面這個是主頁面.JSP文件
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