使用C3P0改造JDBC对数据库的连接

package lesson15_jdbc;import com.mchange.v2.c3p0.ComboPooledDataSource;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;public class C3P0_lianjiechi {  public static void main(String[] args) {    //使用自定义配置    ComboPooledDataSource dataSource1=new ComboPooledDataSource();    //使用自定义配置    //ComboPooledDataSource dataSource2 = new ComboPooledDataSource("");    //建立连接    try{      Connection conn = dataSource1.getConnection();      String sql="select * from 1_mytable1";      PreparedStatement pst=conn.prepareStatement(sql);      ResultSet res = pst.executeQuery();      while(res.next()){        System.out.println(res.getString("n")+"->"+res.getString("age")+"->"+res.getString("gender"));      }      res.close();      pst.close();      conn.close();    }catch (SQLException e){      e.printStackTrace();    }  }}

<c3p0-config>  <!-- 默认配置，如果没有指定则使用这个配置 -->  <default-config>   <!-- 基本配置 -->   <property name="driverClass">com.mysql.jdbc.Driver</property>   <property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/1_mydata</property>   <property name="user">root</property>   <property name="password">123456</property>     <!--扩展配置-->   <property name="checkoutTimeout">30000</property>   <property name="idleConnectionTestPeriod">30</property>   <property name="initialPoolSize">10</property>   <property name="maxIdleTime">30</property>   <property name="maxPoolSize">100</property>   <property name="minPoolSize">10</property>   <property name="maxStatements">200</property>  </default-config>       <!-- 命名的配置 -->  <named-config name="Space_c3p0">   <property name="driverClass">com.mysql.jdbc.Driver</property>   <property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/1_mydata</property>   <property name="user">root</property>   <property name="password">123456</property>         <!-- 如果池中数据连接不够时一次增长多少个 -->   <property name="acquireIncrement">5</property>   <property name="initialPoolSize">20</property>   <property name="minPoolSize">10</property>   <property name="maxPoolSize">40</property>   <property name="maxStatements">20</property>   <property name="maxStatementsPerConnection">5</property>  </named-config></c3p0-config>