c3p0配置介绍

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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

 

<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

    jdbc.driverClassName=com.mysql.jdbc.Driver  
    jdbc.url=jdbc:mysql://localhost/iecms  
    jdbc.username=root  
    jdbc.password=  

 

[ 1 ]、基础测试

 

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 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>

 

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

<!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>

 

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

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