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>