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。
DBCP的配置可以参见：http://www.micmiu.com/j2ee/jdbc-tech/apache-dbcp-simple
proxool的配置介绍也已经发表：http://www.micmiu.com/j2ee/jdbc-tech/proxool-simple
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
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<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：
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c3p0-native property name |
hibernate configuration key |
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c3p0.acquireIncrement |
hibernate.c3p0.acquire_increment |
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c3p0.idleConnectionTestPeriod |
hibernate.c3p0.idle_test_period |
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c3p0.initialPoolSize |
not available — uses minimum size |
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c3p0.maxIdleTime |
hibernate.c3p0.timeout |
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c3p0.maxPoolSize |
hibernate.c3p0.max_size |
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c3p0.maxStatements |
hibernate.c3p0.max_statements |
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c3p0.minPoolSize |
hibernate.c3p0.min_size |
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c3p0.testConnectionsOnCheckout |
hibernate.c3p0.validate hibernate 2.x only! |
[ 二 ]、spring、hibernate中的配置示例
c3p0.jdbc.properties
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jdbc.driverClassName=com.mysql.jdbc.Driver jdbc.url=jdbc:mysql://localhost/iecms jdbc.username=root jdbc.password= |
[ 1 ]、基础测试
C3p0DataSourceExample.java:
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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://www.micmiu.com * @author michael sjsky007@gmail.com */ 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:
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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:
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<?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> |
C3p0SpringExample.java:
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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://www.micmiu.com * @author michael sjsky007@gmail.com */ 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：
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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.xml:
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<!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> |
C3p0HibernateExample.java:
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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://www..micmiu.com * @author michael sjsky007@gmail.com */ 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：
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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 |
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