C3P0数据库连接池使用

C3P0数据库连接池使用

1、拷贝jar包：c3p0-0.9.1.2.jar     c3p0-0.9.1.2-jdk1.3.jar    c3p0-oracle-thin-extras-0.9.1.2.jar（oracle需要）

2、书写配制文件放在src目录下：c3p0-config.xml（名字只能是这个，而且配置文件必须放在src根目录下）

3、类C3P0Util

c3p0-config.xml 内容：

    <?xml version="1.0" encoding="UTF-8"?>  
    <c3p0-config>  
        <!-- This is default config! -->  
        <default-config>  
            <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>  
      
        <!-- This is my config for mysql-->  
        <named-config name="mysql">  
            <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"></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>  
        </named-config>  
          
          
        <!-- This is my config for oracle -->  
        <named-config name="oracle">  
            <property name="driverClass">oracle.jdbc.driver.OracleDriver</property>  
            <property name="jdbcUrl">jdbc:oracle:thin:@localhost:1521:orcl</property>  
            <property name="user">scott</property>  
            <property name="password">liang</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>  
        </named-config>  
    </c3p0-config>  

C3P0Util:

    package com.liang.util;  
      
    import java.io.InputStream;  
    import java.sql.Connection;  
    import java.sql.PreparedStatement;  
    import java.sql.ResultSet;  
    import java.sql.SQLException;  
    import java.util.Properties;  
      
    import com.mchange.v2.c3p0.ComboPooledDataSource;  
    /** 
     * 数据库工具类 
     * @author liang 
     * 
     */  
    public class C3P0Util {  
        static ComboPooledDataSource cpds=null;  
        static{  
            //这里有个优点，写好配置文件，想换数据库，简单  
            //cpds = new ComboPooledDataSource("oracle");//这是oracle数据库  
            cpds = new ComboPooledDataSource("mysql");//这是mysql数据库  
        }  
        /** 
         * 获得数据库连接 
         * @return   Connection 
         */  
        public static Connection getConnection(){  
            try {  
                return cpds.getConnection();  
            } catch (SQLException e) {  
                e.printStackTrace();  
                return null;  
            }  
        }  
          
        /** 
         * 数据库关闭操作 
         * @param conn   
         * @param st     
         * @param pst 
         * @param rs 
         */  
        public static void close(Connection conn,PreparedStatement pst,ResultSet rs){  
            if(rs!=null){  
                try {  
                    rs.close();  
                } catch (SQLException e) {  
                    e.printStackTrace();  
                }  
            }  
            if(pst!=null){  
                try {  
                    pst.close();  
                } catch (SQLException e) {  
                    e.printStackTrace();  
                }  
            }  
      
            if(conn!=null){  
                try {  
                    conn.close();  
                } catch (SQLException e) {  
                    e.printStackTrace();  
                }  
            }  
        }  
        /** 
         * 测试DBUtil类 
         * @param args 
         */  
        public static void main(String[] args) {  
            Connection conn=getConnection();  
            System.out.println(conn.getClass().getName());  
            close(conn,null,null);  
        }  
    }  

转自：http://blog.csdn.net/liang5630/article/details/39055805