今天下午花了不少时间才设置好cocoon与MySQL数据库的连接。要设置cocoon和MySQL可大致分为3步：
- 让cocoon能找到JDBC的 jar文件
- 让cocoon预先加载JDBC driver
- 设定连接池
我没有用cocoon自带的java web server，而是用的Tomcat 5.5.17。下载MySQL Connector/J 3.1.12后把mysql-connector-java-3.1.12-bin.jar文件先后复制到了多个目录：
- $JAVA_HOME/jre/lib/ext
- $CATALINA_HOME/common/lib
- $CATALINA_HOME/webapps/cocoon/WEB-INF/lib
重新启动tomcat后日志仍然报告：
cocoon java.sql.SQLException: No suitable driver
意思是cocoon仍然找不到MySQL的MySQL Connector/J 3.1.12。
后来在$CATALINA_HOME/webapps/cocoon/WEB-INF/web.xml文件里第195行添上
com.mysql.jdbc.Driver
就能与MySQL进行连接了。
下面是设定一个连接池的例子：
在cocoon.xconf文件里加上：
<!-- added by Dingjun Jia, mysql connection pool in cocoon.conf -->
<jdbc name="abc" logger="core.datasources.abc">
<pool-controller min="5" max="10"/>
<!-- <auto-commit>false</auto-commit> -->
<!-- 此行若不注释掉，总会得到错误：
Not allowed to define mixed content in the element match at file:/opt/tomcat/webapps/cocoon/abc/sitemap.xmap:80:36 -->
<dburl>jdbc:mysql://localhost/abc</dburl>
<user>jia</user>
<password>password</password>
</jdbc>
P.S:
If we want to use non-latin characters in mySQL, Greek for example, we need to have a more specific connection string: jdbc:mysql://YourHostName:3360/YourDataBaseName?useUnicode=true&characterEncoding=YourEncoding for example: (cocoon.xconf)
<jdbc name="pool_name">
<pool-controller min="5" max="10"/>
<dburl>jdbc:mysql://YourHostName:3360/YourDataBaseName?useUnicode=true&characterEncoding=ISO-8859-7</dburl>
<user>database_user</user>
<password>database_password</password>
</jdbc>
