c3p0配置介绍

继上一篇介绍dbcp的配置，本文重点介绍下c3p0的配置及实例演示。

上一篇DBCP的配置可以参见：http://sjsky.iteye.com/blog/1105674

proxool的配置介绍也已经发表：http://sjsky.iteye.com/blog/1108808

本文的目录结构大致如下 ：
一、参数介绍
二、结合spring、hibernate中的配置示例
[ 一 ]、参数介绍

Xml代码  收藏代码
<c3p0-default-config> 
    <!--当连接池中的连接耗尽的时候c3p0一次同时获取的连接数。Default: 3 --> 
 
    <property name="acquireIncrement">3</property> 
 
    <!--定义在从数据库获取新连接失败后重复尝试的次数。Default: 30 --> 
 
    <property name="acquireRetryAttempts">30</property> 
 
    <!--两次连接中间隔时间，单位毫秒。Default: 1000 --> 
 
    <property name="acquireRetryDelay">1000</property> 
 
    <!--连接关闭时默认将所有未提交的操作回滚。Default: false --> 
 
    <property name="autoCommitOnClose">false</property> 
 
    <!--c3p0将建一张名为Test的空表，并使用其自带的查询语句进行测试。 
        如果定义了这个参数那么属性preferredTestQuery将被忽略。 
        你不能在这张Test表上进行任何操作，它将只供c3p0测试使用。Default: null--> 
    <property name="automaticTestTable">Test</property> 
 
    <!--获取连接失败将会引起所有等待连接池来获取连接的线程抛出异常。 
        但是数据源仍有效保留，并在下次调用getConnection()的时候继续尝试获取连接。 
        如果设为true，那么在尝试获取连接失败后该数据源将申明已断开并永久关闭。Default: false--> 
    　　 
    <property name="breakAfterAcquireFailure">false</property> 
 
    <!--当连接池用完时客户端调用getConnection()后等待获取新连接的时间， 
        超时后将抛出SQLException,如设为0则无限期等待。单位毫秒。Default: 0 --> 
    　　 
    <property name="checkoutTimeout">100</property> 
 
    <!--通过实现ConnectionTester或QueryConnectionTester的类来测试连接。 
        类名需制定全路径。Default: com.mchange.v2.c3p0.impl.DefaultConnectionTester--> 
    　　 
    <property name="connectionTesterClassName"></property> 
 
    <!--指定c3p0 libraries的路径，如果（通常都是这样）在本地即可获得那么无需设置，默认null即可Default: null--> 
    <property name="factoryClassLocation">null</property> 
    <!--作者强烈建议不使用的一个属性--> 
    <property name="forceIgnoreUnresolvedTransactions">false</property> 
    　　 
    <!--每60秒检查所有连接池中的空闲连接。Default: 0 --> 
 
    <property name="idleConnectionTestPeriod">60</property> 
    　　 
    <!--初始化时获取三个连接，取值应在minPoolSize与maxPoolSize之间。Default: 3 --> 
    　　 
    <property name="initialPoolSize">3</property> 
    　　 
    <!--最大空闲时间,60秒内未使用则连接被丢弃。若为0则永不丢弃。Default: 0 --> 
    　　 
    <property name="maxIdleTime">60</property> 
    　　 
    <!--连接池中保留的最大连接数。Default: 15 --> 
    　　 
    <property name="maxPoolSize">15</property> 
    　　 
    <!--JDBC的标准参数，用以控制数据源内加载的PreparedStatements数量。 
        但由于预缓存的Statements属于单个connection而不是整个连接池。所以设置这个参数需要考虑到多方面的因素. 
        如果maxStatements与maxStatementsPerConnection均为0，则缓存被关闭。Default: 0--> 
    　　 
    <property name="maxStatements">100</property> 
    　　 
    <!--maxStatementsPerConnection定义了连接池内单个连接所拥有的最大缓存statements数。Default: 0 --> 
    　　 
    <property name="maxStatementsPerConnection"></property> 
    　　 
    <!--c3p0是异步操作的，缓慢的JDBC操作通过帮助进程完成。扩展这些操作可以有效的提升性能 
        通过多线程实现多个操作同时被执行。Default: 3--> 
    　　 
    <property name="numHelperThreads">3</property> 
    　　 
    <!--当用户调用getConnection()时使root用户成为去获取连接的用户。 
        主要用于连接池连接非c3p0的数据源时。Default: null--> 
    　　 
    <property name="overrideDefaultUser">root</property> 
 
    <!--与overrideDefaultUser参数对应使用的一个参数。Default: null--> 
    　　 
    <property name="overrideDefaultPassword">password</property> 
    　　<!--密码。Default: null--> 
    　　 
    <property name="password"></property> 
    　　 
    <!--定义所有连接测试都执行的测试语句。在使用连接测试的情况下这个一显著提高测试速度。 
        注意：测试的表必须在初始数据源的时候就存在。Default: null--> 
    　　 
    <property name="preferredTestQuery"> 
        select id from tb_c3p0_test where id=1 
    </property> 
    　　 
    <!--用户修改系统配置参数执行前最多等待300秒。Default: 300 --> 
    　　 
    <property name="propertyCycle">300</property> 
    　　 
    <!--因性能消耗大请只在需要的时候使用它。如果设为true那么在每个connection提交的时候都将校验其有效性。 
        建议使用idleConnectionTestPeriod或automaticTestTable等方法来提升连接测试的性能。Default: false --> 
    　　 
    <property name="testConnectionOnCheckout">false</property> 
    <!--如果设为true那么在取得连接的同时将校验连接的有效性。Default: false --> 
    　　 
    <property name="testConnectionOnCheckin">true</property> 
    <!--用户名。Default: null--> 
    <property name="user">root</property> 
    <!--密码。Default: null--> 
    <property name="password"></property> 
 
</c3p0-default-config> 

和hibernate配置属性的对照表：

c3p0-native property name hibernate configuration key
c3p0.acquireIncrement hibernate.c3p0.acquire_increment
c3p0.idleConnectionTestPeriod hibernate.c3p0.idle_test_period
c3p0.initialPoolSize not available -- uses minimum size
c3p0.maxIdleTime hibernate.c3p0.timeout
c3p0.maxPoolSize hibernate.c3p0.max_size
c3p0.maxStatements hibernate.c3p0.max_statements
c3p0.minPoolSize hibernate.c3p0.min_size
c3p0.testConnectionsOnCheckout
hibernate.c3p0.validate hibernate 2.x only!


[ 二 ]、spring、hibernate中的配置示例

c3p0.jdbc.properties
Java代码  收藏代码
jdbc.driverClassName=com.mysql.jdbc.Driver   
jdbc.url=jdbc:mysql://localhost/iecms   
jdbc.username=root   
jdbc.password=   

[ 1 ]、基础测试

Java代码  收藏代码
package michael.jdbc.c3p0; 
 
import java.sql.Connection; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
import java.util.Properties; 
 
import javax.sql.DataSource; 
 
import michael.jdbc.dbcp.DbcpDataSourceExample; 
 
import com.mchange.v2.c3p0.ComboPooledDataSource; 
 
/**
* @see http://sjsky.iteye.com
* @author michael [email protected]
*/ 
public class C3p0DataSourceExample { 
 
    /**
     * @param args
     */ 
    public static void main(String[] args) { 
 
        String testSql = "select * from TB_MYTEST"; 
        String cfgFileName = "c3p0.jdbc.properties"; 
 
        System.out.println("init c3p0 ComboPooledDataSource start "); 
        DataSource dataSource = initDataSource(cfgFileName); 
        System.out.println("ComboPooledDataSource init done."); 
 
        Connection conn = null; 
        Statement stmt = null; 
        ResultSet rset = null; 
 
        try { 
            System.out.println("Creating connection start."); 
            conn = dataSource.getConnection(); 
 
            System.out.println("Creating statement start."); 
            stmt = conn.createStatement(); 
 
            System.out.println("Executing statement start."); 
            rset = stmt.executeQuery(testSql); 
 
            System.out.println("executeQuery Results:"); 
            int numcols = rset.getMetaData().getColumnCount(); 
 
            while (rset.next()) { 
                for (int i = 1; i <= numcols; i++) { 
                    System.out.print("\t" + rset.getString(i)); 
                } 
                System.out.println(""); 
            } 
            System.out.println("Results display done."); 
        } catch (SQLException e) { 
            e.printStackTrace(); 
        } finally { 
            try { 
                if (rset != null) 
                    rset.close(); 
            } catch (Exception e) { 
                e.printStackTrace(); 
            } 
            try { 
                if (stmt != null) 
                    stmt.close(); 
            } catch (Exception e) { 
                e.printStackTrace(); 
            } 
            try { 
                if (conn != null) 
                    conn.close(); 
            } catch (Exception e) { 
                e.printStackTrace(); 
            } 
 
        } 
    } 
 
    /**
     * @param cfgFileName
     * @return DataSource
     */ 
    public static DataSource initDataSource(String cfgFileName) { 
        ComboPooledDataSource ds = new ComboPooledDataSource(); 
        try { 
            Properties cfgpp = new Properties(); 
            cfgpp.load(C3p0DataSourceExample.class 
                    .getResourceAsStream(cfgFileName)); 
            ds.setDriverClass(cfgpp.getProperty("jdbc.driverClassName")); 
            ds.setJdbcUrl(cfgpp.getProperty("jdbc.url")); 
            ds.setUser(cfgpp.getProperty("jdbc.username")); 
            ds.setPassword(cfgpp.getProperty("jdbc.password")); 
        } catch (Exception e) { 
            e.printStackTrace(); 
            return null; 
        } 
 
        return ds; 
    } 
 
} 

运行结果
init c3p0 ComboPooledDataSource start
ComboPooledDataSource init done.
Creating connection start.
Creating statement start.
Executing statement start.
executeQuery Results:
1 batch_add_0 2011-06-16 14:29:08.0
2 batch_add_1 2011-06-16 14:29:08.0
3 batch_add_2 2011-06-16 14:29:08.0
4 batch_add_3 2011-06-16 14:29:08.0
5 batch_add_4 2011-06-16 14:29:08.0
Results display done.

[ 2 ]、结合spring的配置测试

c3p0.ds.spring.xml
Xml代码  收藏代码
<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"> 
<beans> 
    <bean id="propertyConfigurer" 
        class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> 
        <property name="locations"> 
            <list> 
                <value> 
                    classpath:michael/jdbc/c3p0/c3p0.jdbc.properties 
                </value> 
            </list> 
        </property> 
    </bean> 
 
    <bean id="c3p0DataSource" 
        class="com.mchange.v2.c3p0.ComboPooledDataSource" 
        destroy-method="close"> 
        <property name="driverClass" value="${jdbc.driverClassName}" /> 
        <property name="jdbcUrl" value="${jdbc.url}" /> 
        <property name="user" value="${jdbc.username}" /> 
        <property name="password" value="${jdbc.password}" /> 
 
        <property name="minPoolSize" value="1" /> 
        <property name="maxPoolSize" value="20" /> 
        <property name="maxIdleTime" value="1800" /> 
        <property name="acquireIncrement" value="2" /> 
        <property name="maxStatements" value="0" /> 
        <property name="initialPoolSize" value="2" /> 
        <property name="idleConnectionTestPeriod" value="1800" /> 
        <property name="acquireRetryAttempts" value="30" /> 
        <property name="breakAfterAcquireFailure" value="true" /> 
        <property name="testConnectionOnCheckout" value="false" /> 
    </bean> 
 
</beans> 

Java代码  收藏代码
package michael.jdbc.c3p0; 
 
import java.sql.Connection; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
 
import javax.sql.DataSource; 
 
import org.springframework.context.ApplicationContext; 
import org.springframework.context.support.ClassPathXmlApplicationContext; 
 
import com.mchange.v2.c3p0.ComboPooledDataSource; 
 
/**
* @see http://sjsky.iteye.com
* @author michael [email protected]
*/ 
public class C3p0SpringExample { 
 
    /**
     * @param args
     */ 
    public static void main(String[] args) { 
 
        System.out.println("c3p0.ds.spring.xml init start "); 
        ApplicationContext appCt = new ClassPathXmlApplicationContext( 
                "michael/jdbc/c3p0/c3p0.ds.spring.xml"); 
 
        System.out.println("spring bean create ComboPooledDataSource"); 
        DataSource dataSource = (ComboPooledDataSource) appCt 
                .getBean("c3p0DataSource"); 
 
        String testSql = "select * from TB_MYTEST"; 
 
        Connection conn = null; 
        Statement stmt = null; 
        ResultSet rset = null; 
 
        try { 
            System.out.println("Creating connection start."); 
            conn = dataSource.getConnection(); 
 
            System.out.println("Creating statement start."); 
            stmt = conn.createStatement(); 
 
            System.out.println("Executing statement start."); 
            rset = stmt.executeQuery(testSql); 
 
            System.out.println("executeQuery Results:"); 
            int numcols = rset.getMetaData().getColumnCount(); 
 
            while (rset.next()) { 
                for (int i = 1; i <= numcols; i++) { 
                    System.out.print("\t" + rset.getString(i)); 
                } 
                System.out.println(""); 
            } 
            System.out.println("Results display done."); 
        } catch (SQLException e) { 
            e.printStackTrace(); 
        } finally { 
            try { 
                if (rset != null) 
                    rset.close(); 
            } catch (Exception e) { 
                e.printStackTrace(); 
            } 
            try { 
                if (stmt != null) 
                    stmt.close(); 
            } catch (Exception e) { 
                e.printStackTrace(); 
            } 
            try { 
                if (conn != null) 
                    conn.close(); 
            } catch (Exception e) { 
                e.printStackTrace(); 
            } 
 
        } 
 
    } 
} 

运行结果：
c3p0.ds.spring.xml init start
spring bean create ComboPooledDataSource
Creating connection start.
Creating statement start.
Executing statement start.
executeQuery Results:
1 batch_add_0 2011-06-16 14:29:08.0
2 batch_add_1 2011-06-16 14:29:08.0
3 batch_add_2 2011-06-16 14:29:08.0
4 batch_add_3 2011-06-16 14:29:08.0
5 batch_add_4 2011-06-16 14:29:08.0
Results display done.


[ 3 ]、结合hibernate的配置测试

hibernate.cfg.xm
Xml代码  收藏代码
<!DOCTYPE hibernate-configuration 
    PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" 
    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 
 
<hibernate-configuration> 
 
    <session-factory> 
        <property name="connection.driver_class"> 
            com.mysql.jdbc.Driver 
        </property> 
 
        <!-- 连接数据库的URL--> 
        <property name="connection.url"> 
            jdbc:mysql://localhost:3306/iecms 
        </property> 
 
        <property name="connection.useUnicode">true</property> 
        <property name="connection.characterEncoding">UTF-8</property> 
 
        <!--连接的登录名--> 
        <property name="connection.username">root</property> 
 
        <!--登录密码--> 
        <property name="connection.password"></property> 
 
        <!-- C3P0连接池设定--> 
        <property name="hibernate.connection.provider_class"> 
            org.hibernate.connection.C3P0ConnectionProvider 
        </property> 
        <!-- 最大连接数 --> 
        <property name="hibernate.c3p0.max_size">20</property> 
        <!-- 最小连接数 --> 
        <property name="hibernate.c3p0.min_size">5</property> 
        <!-- 获得连接的超时时间,如果超过这个时间,会抛出异常，单位毫秒 --> 
        <property name="hibernate.c3p0.timeout">120</property> 
        <!-- 最大的PreparedStatement的数量 --> 
        <property name="hibernate.c3p0.max_statements">100</property> 
        <!-- 每隔120秒检查连接池里的空闲连接 ，单位是秒--> 
        <property name="hibernate.c3p0.idle_test_period">120</property> 
        <!-- 当连接池里面的连接用完的时候，C3P0一下获取的新的连接数 --> 
        <property name="hibernate.c3p0.acquire_increment">2</property> 
        <!-- 每次都验证连接是否可用 --> 
        <property name="hibernate.c3p0.validate">true</property> 
 
        <property name="show_sql">true</property> 
 
        <property name="current_session_context_class">thread</property> 
 
        <property name="dialect"> 
            org.hibernate.dialect.MySQL5Dialect 
        </property> 
 
        <property name="hbm2ddl.auto">update</property> 
    </session-factory> 
</hibernate-configuration> 

Java代码  收藏代码
package michael.jdbc.c3p0; 
 
import java.util.List; 
 
import org.hibernate.Session; 
import org.hibernate.SessionFactory; 
import org.hibernate.Transaction; 
import org.hibernate.cfg.AnnotationConfiguration; 
import org.hibernate.cfg.Configuration; 
 
/**
* @see http://sjsky.iteye.com
* @author michael [email protected]
*/ 
public class C3p0HibernateExample { 
 
    /**
     * @param args
     */ 
    public static void main(String[] args) { 
        SessionFactory sessionFactory = null; 
        try { 
            System.out.println("c3p0/hibernate.cfg.xml configure"); 
            Configuration config = new AnnotationConfiguration() 
                    .configure("michael/jdbc/c3p0/hibernate.cfg.xml"); 
 
            System.out.println(" create sessionFactory "); 
            sessionFactory = config.buildSessionFactory(); 
 
            System.out.println(" create session "); 
            Session session = sessionFactory.getCurrentSession(); 
            String testSql = "select * from TB_MYTEST"; 
 
            System.out.println(" beginTransaction "); 
            Transaction ta = session.beginTransaction(); 
            org.hibernate.Query query = session.createSQLQuery(testSql); 
            List<Object[]> list = query.list(); 
            System.out.println(" createSQLQuery list: "); 
            for (Object[] objArr : list) { 
                for (Object obj : objArr) { 
                    System.out.print("\t" + obj); 
                } 
                System.out.println(""); 
            } 
            System.out.println(" beginTransaction commit "); 
            ta.commit(); 
 
        } catch (Exception e) { 
            e.printStackTrace(); 
        } finally { 
            if (null != sessionFactory) { 
                sessionFactory.close(); 
            } 
 
        } 
 
    } 
} 
运行结果：
c3p0/hibernate.cfg.xml configure
create sessionFactory
create session
beginTransaction
Hibernate: select * from TB_MYTEST
createSQLQuery list:
1 batch_add_0 2011-06-16 14:29:08.0
2 batch_add_1 2011-06-16 14:29:08.0
3 batch_add_2 2011-06-16 14:29:08.0
4 batch_add_3 2011-06-16 14:29:08.0
5 batch_add_4 2011-06-16 14:29:08.0
beginTransaction commit

转载请注明来自：Michael's blog @ http://sjsky.iteye.com