<c3p0-config>

  <!-- 使用默认的配置读取连接池对象 -->

  <default-config>

      <!--  连接参数 -->

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

    <property name="jdbcUrl">jdbc:mysql://localhost:3306/test</property>

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

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

    <!-- 连接池参数 -->

    <property name="initialPoolSize">5</property>

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

    <property name="checkoutTimeout">3000</property>

  </default-config>

  <named-config name="otherc3p0">

    <!--  连接参数 -->

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

    <property name="jdbcUrl">jdbc:mysql://localhost:3306/day25</property>

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

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

    <!-- 连接池参数 -->

    <property name="initialPoolSize">5</property>

    <property name="maxPoolSize">8</property>

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

  </named-config>

</c3p0-config>

package com.huang;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class DbUtils {

    private static DataSource dataSource = new ComboPooledDataSource();// 可以加参数，更改连接池配置

    public Connection conn = null;

    public PreparedStatement ps = null;

    public ResultSet rs = null;

    public Connection getconn() {

        try {

            return dataSource.getConnection();

        } catch (SQLException e) {

            e.printStackTrace();

        }

        return null;

    }

    public int update(String sql, Object[] obj) {

        conn = getconn();

        if(conn == null) {

            return 0;

        }

        try {

            ps = conn.prepareStatement(sql);

            if(obj!=null && obj.length>0) {

                for (int i = 0; i < obj.length; i++) {

                    ps.setObject(i+1, obj[i]);

                }

            }

            return ps.executeUpdate();

        } catch (Exception e) {

            e.printStackTrace();

        }

        return 0;

    }

    public void close() {

        if(rs!=null) {

            try {

                rs.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

        if(ps!=null) {

            try {

                ps.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

        if(conn!=null) {

            try {

                conn.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

    }

    public static void main(String[] args) throws Exception {

        DbUtils dbUtil = new DbUtils();

        int update = dbUtil.update("update user_info set username = ? where id = ?", new Object[] {"qq","1"});

        System.out.println(update);

        dbUtil.close();

    }

}