建立配置檔案：c3p0-config.xml（必須放在src目錄下）

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
      <default-config>
            <property name="driverClass">com.mysql.jdbc.Driver</property>
            <property name="jdbcUrl">jdbc:mysql://localhost:3306/jdbc</property>
            <property
 
 name="user">root</property>
            <property name="password">123456</property>

            <property name="acquireIncrement">5</property>
            <property name="initialPoolSize">10</property>
            <property name="minPoolSize">5</property
 
>
            <property name="maxPoolSize">20</property>
      </default-config>

      <named-config name="mysql">
            <property name="driverClass">com.mysql.jdbc.Driver</property>
            <property name="jdbcUrl">jdbc:mysql://localhost:3306/jdbc</property
 
>
            <property name="user">root</property>
            <property name="password">123456</property>

            <property name="acquireIncrement">5</property>
            <property name="initialPoolSize">10</property>
            <property name="minPoolSize">5</property>
            <property name="maxPoolSize">20</property>
      </named-config>


      <named-config name="oracle">
            <property name="driverClass">com.mysql.jdbc.Driver</property>
            <property name="jdbcUrl">jdbc:mysql://localhost:3306/jdbc</property>
            <property name="user">root</property>
            <property name="password">123456</property>

            <property name="acquireIncrement">5</property>
            <property name="initialPoolSize">10</property>
            <property name="minPoolSize">5</property>
            <property name="maxPoolSize">20</property>
      </named-config>
</c3p0-config>

建立工具類

public class C3P0Util {

      private static DataSource ds = new ComboPooledDataSource();

      /**
       * 獲取連結
       * @return
       * @throws SQLException
       */
      public static Connection getConnection() throws SQLException {
            return ds.getConnection();
      }

      /**
       * 獲取資料來源
       * @return
       */
      public static DataSource getDataSource() {
            return ds;
      }

      /**
       * 關閉資源
       * @param rs
       * @param st
       * @param con
       */
      public static void release(ResultSet rs, Statement st, Connection con) {
            try {
                  if (rs != null) {
                        rs.close();
                        rs = null;
                  }
            } catch (SQLException e) {
                  e.printStackTrace();
            }
            try {
                  if (st != null) {
                        st.close();
                        st = null;
                  }
            } catch (SQLException e) {
                  e.printStackTrace();
            }
            try {
                  if (con != null) {
                        con.close();
                        con = null;
                  }
            } catch (SQLException e) {
                  e.printStackTrace();
            }
      }
}

測試程式碼

public class C3p0Test {

      @Test
      public void testAdd(){
            Connection con =null;
            Statement st =null;
            try{
                  con=C3P0Util.getConnection();
                  st=con.createStatement();
                  System.out.println(st);
            }catch(Exception e){
                  e.printStackTrace();
            }finally{
                  C3P0Util.release(null, st, con);
            }
      }
}

需要的依賴包

• c3p0-0.9.1.2
• c3p0-0.9.1.2-jdk1.3
• c3p0-oracle-thin-extras-0.9.1.2（相容oracle）
• mysql-connector-java-5.0.8-bin