[英]Caused by: java.lang.ClassCastException: org.apache.commons.dbcp.PoolingDataSource cannot be cast to javax.sql.DataSource
[英]ClassCastException DataSource cannot be cast to javax.sql.ConnectionPoolDataSource
我得到了这个例外:
java.lang.ClassCastException: org.apache.tomcat.jdbc.pool.DataSource cannot be cast to javax.sql.ConnectionPoolDataSource
当我尝试运行我的webapp(在Tomcat6中)时,使用与Tomcat7无缝协作的tomcat jdbc池
我已经在tomcat 6 lib文件夹中包含了这些jar:
tomcat-jdbc.jar
tomcat-juli.jar
可能是什么问题呢?
更新:
protected static Connection getConnection() throws NamingException, SQLException {
InitialContext cxt = new InitialContext();
String jndiName = "java:/comp/env/jdbc/MyDBHrd";
ConnectionPoolDataSource dataSource = (ConnectionPoolDataSource) cxt.lookup(jndiName); // ClassCastException here....
PooledConnection pooledConnection = dataSource.getPooledConnection();
Connection conn = pooledConnection.getConnection();
return conn; // Obtain connection from pool
}
组态:
<Resource name="jdbc/MyDBHrd"
auth="Container"
type="javax.sql.DataSource"
factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
testWhileIdle="true"
testOnBorrow="true"
testOnReturn="false"
validationQuery="SELECT 1"
validationInterval="30000"
timeBetweenEvictionRunsMillis="30000"
maxActive="5000"
minIdle="10"
maxWait="10000"
initialSize="20"
removeAbandonedTimeout="120"
removeAbandoned="true"
logAbandoned="false"
minEvictableIdleTimeMillis="30000"
jmxEnabled="true"
jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;
org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer"
username="sa"
password="password"
driverClassName="net.sourceforge.jtds.jdbc.Driver"
url="jdbc:jtds:sqlserver://192.168.114.130/MyDB"/>
当我更改“类型”时:
type="javax.sql.ConnectionPoolDataSource"
我收到这个警告:
WARNING: javax.sql.ConnectionPoolDataSource is not a valid class name/type for this JNDI factory.
导致getConnection()
返回NULL。
进口:
import java.io.IOException;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.ConnectionPoolDataSource;
import javax.sql.PooledConnection;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
作为最终用户,您永远不必直接使用ConnectionPoolDataSource
。 它旨在作为物理连接的工厂( PooledConnection
)。 PooledConnection
保存在连接PooledConnection
。 当您执行DataSource.getConnection
,数据源将从池中PooledConnection
,并将使用PooledConnection.getConnection()
获得的逻辑连接作为最终用户返回给您,并在该逻辑时将物理连接返回到池Connection
已关闭。
所以构造是
User -- uses --> DataSource (with connectionpooling) -- uses --> ConnectionPoolDataSource
要么
ConnectionPoolDataSource --> creates PooledConnection --> DataSource --> returns Connection --> User
如果DataSource
提供或不提供连接DataSource
则使用DataSource
与事实无关(它应该对您透明)。
另请参阅我之前对另一个问题的回答: https : //stackoverflow.com/a/12651163/466862
换句话说,您的代码应更改为:
protected static Connection getConnection() throws NamingException, SQLException {
InitialContext cxt = new InitialContext();
String jndiName = "java:/comp/env/jdbc/MyDBHrd";
DataSource dataSource = (DataSource) cxt.lookup(jndiName);
Connection conn = dataSource.getConnection();
return conn;
}
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