Struts itself has connection pooling support using DBCP(Database Connection Pooling). commons-pool-1.2.jar which comes with Sturts download.
For configuring DBCP with sturts,
URL Example: <data-sources>
<data-source type="org.apache.commons.dbcp.BasicDataSource" key="mysql">
<set-property property="driverClassName" value="com.mysql.jdbc.Driver"></set-property>
<set-property property="url" value="jdbc:mysql://testServer/test"></set-property>
<set-property property="username" value="test"></set-property>
<set-property property="password" value="test"></set-property>
<set-property property= "maxCount" value= "100"></set-property>
<set-property property= "minCount" value= "0"></set-property>
</data-source>
</data-sources>