当Tomcat遭遇JBDC Driver，出现 'Cannot create resource instance' ！

用Tomcat，最担心的就是配置JNDI的DataSource的时候出现问题，随着各大厂商发布自己的JDBC的实现，兼容性的问题也就越来也突出了...

一般我们都是用Tomcat自带的DBCP来处理，配置如下：

<Resource name="jdbc/MyDS" auth="Container" type="javax.sql.DataSource" />

<ResourceParams name="jdbc/MyDS">

<parameter>

<name>driverClassName</name>

<value>oracle.jdbc.driver.OracleDriver</value>

</parameter>

<parameter>

<name>driverName</name>

<value>jdbc:oracle:thin:@server:port:sid</value>

</parameter>

<parameter>

<name>user</name>

<value>########</value>

</parameter>

<parameter>

<name>password</name>

<value>########</value>

</parameter>

</ResourceParams>

Oracle JDBC Driver for JDK 1.4 or JDK 1.5

http://www.oracle.com/technology/software/tech/java/sqlj_jdbc/htdocs/jdbc_10201.html

不过这个写法，如果在JBuilderX中，跑Tomcat 4.1，加上最新版的 Oracle JDBC Driver会存在问题，系统抛出的错误为：

javax.naming.NamingException: Cannot create resource instance

at org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFactory.java:189)

at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:301)

at org.apache.naming.NamingContext.lookup(NamingContext.java:834)

at org.apache.naming.NamingContext.lookup(NamingContext.java:181)

at org.apache.naming.NamingContext.lookup(NamingContext.java:822)

at org.apache.naming.NamingContext.lookup(NamingContext.java:181)

at org.apache.naming.NamingContext.lookup(NamingContext.java:822)

at org.apache.naming.NamingContext.lookup(NamingContext.java:181)

at org.apache.naming.NamingContext.lookup(NamingContext.java:822)

at org.apache.naming.NamingContext.lookup(NamingContext.java:194)

at org.apache.naming.SelectorContext.lookup(SelectorContext.java:183)

at javax.naming.InitialContext.lookup(InitialContext.java:347)

看来DBCP针对java.sql.DataSource相关的实现与ojdbc14.jar存在兼容性的问题，需要按照下面的写法才能OK：

<Resource name="jdbc/MyDS" type="oracle.jdbc.pool.OracleConnectionCacheImpl"/>

<ResourceParams name="jdbc/MyDS">

<parameter>

<name>factory</name>

<value>oracle.jdbc.pool.OracleDataSourceFactory</value>

</parameter>

<parameter>

<name>driverClassName</name>

<value>oracle.jdbc.driver.OracleDriver</value>

</parameter>

<parameter>

<name>url</name>

<value>jdbc:oracle:thin:@server:port:sid</value>

</parameter>

<parameter>

<name>user</name>

<value>########</value>

</parameter>

<parameter>

<name>password</name>

<value>########</value>

</parameter>

</ResourceParams>

原来Oracle自己实现了DataSource的工厂类来管理DataSource的建立！

同样发现微软的SQL Server 2000 Driver for JDBC Service Pack 3也存在这个问题！

http://www.microsoft.com/downloads/details.aspx?familyid=07287b11-0502-461a-b138-2aa54bfdc03a&displaylang=en

需要如下配置：

<Resource name="jdbc/MyDS" auth="Container" type="com.microsoft.jdbcx.sqlserver.SQLServerDataSource"/>

<ResourceParams name="jdbc/MyDS">

<parameter>

<name>factory</name>

<value>com.microsoft.jdbcx.sqlserver.SQLServerDataSourceFactory</value>

</parameter>

<parameter>

<name>driverClassName</name>

<value>com.microsoft.jdbcx.sqlserver.SQLServerDataSource</value>

</parameter>

<parameter>

<name>driverName</name>

<value>SQLServer</value>

</parameter>

<parameter>

<name>description</name>

<value>My DataSource</value>

</parameter>

<parameter>

<name>serverName</name>

<value>########</value>

</parameter>

<parameter>

<name>portNumber</name>

<value>1433</value>

</parameter>

<parameter>

<name>selectMethod</name>

<value>cursor</value>

</parameter>

<parameter>

<name>databaseName</name>

<value>########</value>

</parameter>

<parameter>

<name>user</name>

<value>########</value>

</parameter>

<parameter>

<name>password</name>

<value>########</value>

</parameter>

<parameter>

<name>loginTimeout</name>

<value>3000</value>

</parameter>

</ResourceParams>