<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xml>
<c3p0-config>
<!--下面四個是數據庫連接必須需要的東西 -->
 <named-config name="MySQL">  <!--為你的數據庫起一個名字,我的叫MySQL -->
 <property name="driverClass">com.mysql.jdbc.Driver</property> 
 <property name="jdbcUrl">jdbc:mysql:localhost:3306/jdbc_01</property>
 <property name="user">root</property>  <!--數據庫賬號 -->
 <property name="password">root</property> <!--數據庫密碼 -->
 
  <!-- 若數據庫鏈接數量不足的時候,向數據庫申請的連接數量 -->
  <property name="acquireIncrement">5</property>
  <!-- 初始化數據庫連接池連接的數量 -->
  <property name="initialPoolSize">10</property>
  <!-- 數據庫連接池中最小連接數 -->
  <property name="minPoolSize">5</property>
  <!-- 數據庫連接池中最大連接數 -->
  <property name="maxPoolSize">100</property>
  <!-- C3P0數據庫連接池可以維護的Statement的數量 -->
  <property name="maxStatements">2</property> 
  <!-- 每個連接可同時使用Statement的數量 -->
  <property name="maxStatementsPerConnection">5</property>
 </named-config>
</c3p0-config>

package cn.qhy.jdbc;

import java.io.IOException;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class MyDBUtils {
 private static DataSource dataSource;
 static {// 靜態代碼塊,只執行一次
 dataSource = new ComboPooledDataSource("MySQL");
 }

 /**
 * 
 * @return
 * @throws SQLException
 */
 public static Connection getConnection() throws SQLException {
 return dataSource.getConnection();
 }

 /**
 * 通用的用來關閉數據有關的所有的資源的操作
 */
 public static void close(Connection conn, Statement sta, ResultSet re) {
 if (re != null)
  try {
  re.close();
  } catch (SQLException e) {
  e.printStackTrace();
  }
 if (sta != null)
  try {
  sta.close();
  } catch (SQLException e) {
  e.printStackTrace();
  }
 if (conn != null)
  try {
  conn.close();
  } catch (SQLException e) {
  e.printStackTrace();
  }
 }
}

package cn.qhy.test;

import java.beans.PropertyVetoException;
import java.sql.Connection;
import java.sql.SQLException;

import org.junit.jupiter.api.Test;

import com.mchange.v2.c3p0.ComboPooledDataSource;

import cn.qhy.jdbc.MyDBUtils;

public class C3P0Test {
 /**
 * @throws SQLException
 * 
 */
 @Test
 public void c3p0xmlTest() throws SQLException {
 Connection conn = MyDBUtils.getConnection();
 System.out.println(conn);
 conn.close();
 }
}