package com.learning.utils;

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

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class C3P0Util {
    
    private static DataSource dataSource = new ComboPooledDataSource();

    
    /*没有用配置文件
    private static ComboPooledDataSource dataSource = new ComboPooledDataSource();
    static{
        try {
            dataSource.setDriverClass( "com.mysql.jdbc.Driver" ); //loads the jdbc driver
            dataSource.setJdbcUrl( "jdbc:mysql://localhost:3306/book" ); 
            dataSource.setUser("root"); 
            dataSource.setPassword("root");
        } catch (PropertyVetoException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
    }*/
    
    //从数据源中获得连接
    public static Connection getConnection() {
        try {
            return dataSource.getConnection();
        } catch (SQLException e) {
            throw new RuntimeException("数据库连接失败");
        }
    }
    
    //释放连接 
    public static void release(Connection connection,Statement statement,ResultSet resultSet) {
        if (connection!=null) {
            try {
                //把不用的connection对象放回连接池（实际用了装饰模式）
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            connection=null;
        }
        if (statement!=null) {
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            statement=null;
        }
        if (resultSet!=null) {
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            resultSet=null;
        }
    }
    
}

<c3p0-config>
    <default-config>
    
    
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/book</property>
        <property name="user">root</property>
        <property name="password">root</property>
            
        <property name="automaticTestTable">con_test</property>
        <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>
        <user-overrides user="test-user">
            <property name="maxPoolSize">10</property>
            <property name="minPoolSize">1</property>
            <property name="maxStatements">0</property>
        </user-overrides>
    </default-config> 
    
</c3p0-config>