<c3p0-config>

     <!--  默认配置，有且仅可出现一次 ，如果没有指定则使用这个配置 -->

     <default-config>

         <!-- 连接超时时间 30秒 -->

         <property name="checkoutTimeout">30000</property>

         <!-- 每30秒检查一次空闲时间 -->

         <property name="idleConnectionTestPeriod">30</property>

         <!-- 初始化池大小 -->

         <property name="initialPoolSize">10</property>

         <!-- 最多的connection的空闲时间 -->

         <property name="maxIdleTime">30</property>

         <!-- 池中最大连接数 -->

         <property name="maxPoolSize">100</property>

         <!-- 池中最小连接数 -->

         <property name="minPoolSize">10</property>

         <!-- 批处理的语句 -->

         <property name="maxStatements">50</property>

         <!-- 每次增长几个连接 -->

         <property name="acquireIncrement">3</property>        

         <property name="driverClass">com.mysql.jdbc.Driver</property>

         <property name="jdbcUrl">

             <![CDATA[jdbc:mysql:///jdbcdb?useUnicode=true&characterEncoding=UTF-8]]>

         </property>

         <property name="user">root</property>

         <property name="password">mysql</property>    

     </default-config>

     <!-- 命名的配置 -->

     <named-config name="MyDb">

         <property name="driverClass">com.mysql.jdbc.Driver</property>

         <property name="jdbcUrl">

             <![CDATA[jdbc:mysql://localhost/bookstore]]>

         </property>

         <property name="user">root</property>

         <property name="password">mysql</property>

         <property name="acquireIncrement">5</property><!-- 如果池中数据连接不够时一次增长多少个 -->

         <property name="initialPoolSize">100</property>

         <property name="minPoolSize">50</property>

         <property name="maxPoolSize">1000</property>

         <property name="maxStatements">0</property>

         <property name="maxStatementsPerConnection">5</property> <!-- he's important, but there's only one of him -->

     </named-config>

 </c3p0-config> 

 c3p0-config.xml

 private static DataSource ds;

     private DataSourceUtils(){}

     static{

         ds=new  ComboPooledDataSource();//默认读取c3p0中默认配置

         //new ComboPooledDataSource("MyDb");//读取c3p0配置在的named-config中的配置

     }

     public static DataSource getDataSource()

     {

         return ds;

     }