『提问』Tomcat5 数据源配置错误

软件环境：
Tomcat5
mysql4
配置文件：
<DefaultContext reloadable="true"/>
<Context path="/RM" docBase="RM"
        debug="5" reloadable="true" crossContext="true">

  <Logger className="org.apache.catalina.logger.FileLogger"
     prefix="localhost_DBTest_log." suffix=".txt"
     timestamp="true"/>

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

  <ResourceParams name="RMDB">
    <parameter>
      <name>factory</name>
      <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
    </parameter>

    <!-- Maximum number of dB connections in pool. Make sure you
configure your mysqld max_connections large enough to handle
all of your db connections. Set to 0 for no limit.
-->
    <parameter>
      <name>maxActive</name>
      <value>100</value>
    </parameter>

    <!-- Maximum number of idle dB connections to retain in pool.
Set to 0 for no limit.
-->
    <parameter>
      <name>maxIdle</name>
      <value>30</value>
    </parameter>

    <!-- Maximum time to wait for a dB connection to become available
in ms, in this example 10 seconds. An Exception is thrown if
this timeout is exceeded.  Set to -1 to wait indefinitely.
-->
    <parameter>
      <name>maxWait</name>
      <value>10000</value>
    </parameter>

    <!-- MySQL dB username and password for dB connections  -->
    <parameter>
     <name>username</name>
     <value>root</value>
    </parameter>
    <parameter>
     <name>password</name>
     <value></value>
    </parameter>

    <!-- Class name for the old mm.mysql JDBC driver - uncomment this entry and comment next
if you want to use this driver - we recommend using Connector/J though
    <parameter>
       <name>driverClassName</name>
       <value>org.gjt.mm.mysql.Driver</value>
    </parameter>
     -->
   
    <!-- Class name for the official MySQL Connector/J driver -->
    <parameter>
       <name>driverClassName</name>
       <value>com.mysql.jdbc.Driver</value>
    </parameter>
   
    <!-- The JDBC connection url for connecting to your MySQL dB.
The autoReconnect=true argument to the url makes sure that the
mm.mysql JDBC Driver will automatically reconnect if mysqld closed the
connection.  mysqld by default closes idle connections after 8 hours.
-->
    <parameter>
      <name>url</name>
      <value><![CDATA[url=jdbc:mysql://localhost:3306/rmdb?useUnicode=true&characterEncoding=GB2312]]></value>
    </parameter>
  </ResourceParams>
</Context>
错误提示信息：
org.apache.commons.dbcp.SQLNestedException: Cannot create JDBC driver of class 'com.mysql.jdbc.Driver' for connect URL 'url=jdbc:mysql://localhost:3306/rmdb?useUnicode=true&characterEncoding=GB2312'
at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:780)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:540)
at com.rm.servlet.TestDataSource.doGet(TestDataSource.java:85)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:534)
Caused by: java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getDriver(DriverManager.java:243)
at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:773)
... 28 more
你的分析：
注意：java.sql.SQLException: No suitable driver

我在网上搜了下，好像没有人遇到类似的错误。

我查了下Tomcat5的文档，说是支持jdbc2.0，就把原来的mysqlconnector3
.0换作mysqlconnector2.0的，可是问题依旧。

我已经将jdbc的驱动程序的包放到common/lib下面。

server.xml的配置如上面。

补充一下：
我使用如下代码可以进行连接：

				
Class.forName("com.mysql.jdbc.Driver");.newInstance();;
				
conn =DriverManager.getConnection("jdbc:mysql://localhost:3306/rmdb?user=root&password=&useUnicode=true&characterEncoding=GB2312");;

根据我的体会：

mysql4.0.x以下版本用mysqlconnector3.0.x版本
mysql4.1.x版本用mysqlconnector3.1.x版本

我的jdbc3.0.8是怎么也连不上我的mysql4.1.1alpha，换成jdbc3.1.11alpha马上就好用了。

不知道对你是否有用，good luck

>From David:

Here's first what should be in
{TOMCAT_HOME}/conf/Catalina/localhost/DBTest.xml:

<Context path="/DBTest" docBase="DBTest"
        debug="0" privileged="false">

  <!-- Loggers, valves, other stuff here -->

  <Resource name="jdbc/DbTest"
            auth="container"
            type="javax.sql.DataSource"/>

    <ResourceParams name="jdbc/DbTest">
    <parameter>
      <name>factory</name>
      <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
    </parameter>

    <parameter>
      <name>maxActive</name>
      <value>100</value>
    </parameter>

    <parameter>
      <name>maxIdle</name>
      <value>30</value>
    </parameter>

    <parameter>
      <name>maxWait</name>
      <value>100000</value>
    </parameter>

    <!-- Customize with your database username -->
    <parameter>
      <name>username</name>
      <value>DBTestUser</value>
    </parameter>

    <!-- Customize with your database password here -->
    <parameter>
      <name>password</name>
      <value>*********</value>

    <parameter>
      <name>driverClassName</name>
      <value>com.mysql.jdbc.Driver</value>
    </parameter>

    <!-- Customize with your mysql url -->
    <parameter>
      <name>url</name>
      <value>jdbc:mysql://localhost:3306/DBTest?autoReconnect=true</value>
    </parameter>
  </ResourceParams>

</Context>

-----------------------------------------------------
Ok, now what should be in {TOMCAT_HOME}/webapps/DBTest/WEB-INF/web.xml:

<?xml version="1.0" encoding="ISO-8859-1"?>

<!DOCTYPE web-app
  PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
  "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd";>

<web-app>
  <display-name>DbTest Application</display-name>

  <!-- All your servlet definitions, mappings, welcome file specs,
taglibs, etc, ...
         are placed here. -->

  <!--+ resource-ref here to make the database pool available in this
application
      +-->
  <resource-ref>
    <description>DBTest Database</description>
    <res-ref-name>jdbc/DbTest</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
  </resource-ref>

</web-app>

---------------------------------------------------------
This exact formula has worked for me in I can't even count how many apps
I've setup.

--David

<Context path="/RMMS" docBase="RMMS"
        debug="0" privileged="false">

  <!-- Loggers, valves, other stuff here -->

  <Resource name="RMDB"
            auth="container"
            type="javax.sql.DataSource"/>

    <ResourceParams name="RMDB">
    <parameter>
      <name>factory</name>
      <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
    </parameter>

    <parameter>
      <name>maxActive</name>
      <value>100</value>
    </parameter>

    <parameter>
      <name>maxIdle</name>
      <value>30</value>
    </parameter>

    <parameter>
      <name>maxWait</name>
      <value>100000</value>
    </parameter>

    <!-- Customize with your database username -->
    <parameter>
      <name>username</name>
      <value>root</value>
    </parameter>

    <!-- Customize with your database password here -->
    <parameter>
      <name>password</name>
      <value></value>
    </parameter>
    <parameter>
      <name>driverClassName</name>
      <value>com.mysql.jdbc.Driver</value>
    </parameter>

    <!-- Customize with your mysql url -->
    <parameter>
      <name>url</name>
      <value>jdbc:mysql://localhost:3306/rmdb?useUnicode=true&characterEncoding=GB2312</value>
    </parameter>
    <parameter>
        <name>removeAbandoned</name>
         <value>true</value>
    </parameter>
    <parameter>
         <name>removeAbandonedTimeout</name>
         <value>60</value>
    </parameter>
  </ResourceParams>
</Context>

-----------------

我的配置文件内容。