http://sjsky.iteye.com/blog/1105674
blog迁移至:http://www.micmiu.com
本文主要介绍apache-dbcp基本参数配置和应用示例,dbcp目前最新版是1.4需要在jdk1.6的环境下运行,如果要在jdk1.4、1.5环境下运行,需要下载前一版本1.3,具体详细可以查看它的官网。
本文结构目录分两大部分:
- 一、基础参数说明
- 二、dbcp在spring、hibernate等应用中的配置示例
c3p0的配置介绍已经发表参见:http://sjsky.iteye.com/blog/1107197
proxool的配置介绍已经发表参见:http://sjsky.iteye.com/blog/1108808
[ 一 ]、参数介绍
[ 1 ]、基础参数说明
- defaultAutoCommit: 对于事务是否 autoCommit, 默认值为 true
- defaultReadOnly:对于数据库是否只能读取, 默认值为 false
- initialSize:连接池启动时创建的初始化连接数量(默认值为0)
- driverClassName:连接数据库所用的 JDBC Driver Class,
- url: 连接数据库的 URL
- username:登陆数据库所用的帐号
- password: 登陆数据库所用的密码
- maxActive: 连接池中可同时连接的最大的连接数,为0则表示没有限制,默认为8
- maxIdle: 连接池中最大的空闲的连接数(默认为8,设 0 为没有限制),超过的空闲连接将被释放,如果设置为负数表示不限制(maxIdle不能设置太小,因为假如在高负载的情况下,连接的打开时间比关闭的时间快,会引起连接池中idle的个数 上升超过maxIdle,而造成频繁的连接销毁和创建)
- minIdle:连接池中最小的空闲的连接数(默认为0,一般可调整5),低于这个数量会被创建新的连接(该参数越接近maxIdle,性能越好,因为连接的创建和销毁,都是需要消耗资源的;但是不能太大,因为在机器很空闲的时候,也会创建低于minidle个数的连接)
- maxWait: 超过时间会丟出错误信息 最大等待时间(单位为 ms),当没有可用连接时,连接池等待连接释放的最大时间,超过该时间限制会抛出异常,如果设置-1表示无限等待(默认为-1,一般可调整为60000ms,避免因线程池不够用,而导致请求被无限制挂起)
- validationQuery: 验证连接是否成功, SQL SELECT 指令至少要返回一行
- removeAbandoned:超过removeAbandonedTimeout时间后,是否进行没用连接的回收(默认为false)
- removeAbandonedTimeout: 超过时间限制,回收五用的连接(默认为 300秒),removeAbandoned 必须为 true
- logAbandoned: 是否记录中断事件, 默认为 false
- <bean id="dbcpDataSource"
- class="org.apache.commons.dbcp.BasicDataSource"
- destroy-method="close">
- <property name="driverClassName"
- value="${jdbc.driverClassName}" />
- <property name="url" value="${jdbc.url}" />
- <property name="username" value="${jdbc.username}" />
- <property name="password" value="${jdbc.password}" />
- <property name="maxActive" value="20" />
- <property name="initialSize" value="1" />
- <property name="maxWait" value="60000" />
- <property name="maxIdle" value="15" />
- <property name="minIdle" value="5" />
- <property name="removeAbandoned" value="true" />
- <property name="removeAbandonedTimeout" value="180" />
- <property name="connectionProperties">
- <value>clientEncoding=utf-8</value>
- </property>
- </bean>
[ 2 ]、validate配置参数说明
- minEvictableIdleTimeMillis:大于0 ,进行连接空闲时间判断,或为0,对空闲的连接不进行验证;默认30分钟
- timeBetweenEvictionRunsMillis:失效检查线程运行时间间隔,如果小于等于0,不会启动检查线程,默认-1
- testOnBorrow:在进行borrowObject进行处理时,对拿到的connection进行validateObject校验,默认为false
- testOnReturn:就是在进行returnObject对返回的connection进行validateObject校验,默认为false
- testWhileIdle:GenericObjectPool中针对pool管理,起了一个Evict的TimerTask定时线程进行控制(可通过设置参数timeBetweenEvictionRunsMillis>0),定时对线程池中的链接进行validateObject校验,对无效的链接进行关闭后,会调用ensureMinIdle,适当建立链接保证最小的minIdle连接数,默认为false
- numTestsPerEvictionRun:每次检查链接的数量,建议设置和maxActive一样大,这样每次可以有效检查所有的链接.
- validateQuery:验证检查执行的sql
- validateQueryTimeout:在执行检查时超时设置,通过statement 设置,statement.setQueryTimeout(validationQueryTimeout)
- <property name="testWhileIdle" value="true" />
- <property name="testOnBorrow" value="false" />
- <property name="testOnReturn" value="false" />
- <property name="validationQuery">
- <value>select sysdate from dual</value>
- </property>
- <property name="validationQueryTimeout" value="1" />
- <property name="timeBetweenEvictionRunsMillis" value="30000" />
- <property name="numTestsPerEvictionRun" value="20" />
[ 二 ]、dbcp在spring、hibernate等应用中的配置示例
dbcp.jdbc.properties
- jdbc.driverClassName=com.mysql.jdbc.Driver
- jdbc.url=jdbc:mysql://localhost/iecms
- jdbc.username=root
- jdbc.password=
[ 1 ]、最基本的应用
- package michael.jdbc.dbcp;
- import javax.sql.DataSource;
- import java.sql.Connection;
- import java.sql.Statement;
- import java.sql.ResultSet;
- import java.sql.SQLException;
- import java.util.Properties;
- import org.apache.commons.dbcp.BasicDataSource;
- /**
- * @see http://sjsky.iteye.com
- * @author michael sjsky007@gmail.com
- */
- public class DbcpDataSourceExample {
- /**
- * @param args
- */
- public static void main(String[] args) {
- String testSql = "select * from TB_MYTEST";
- String cfgFileName = "dbcp.jdbc.properties";
- System.out.println("Setting up data source.");
- DataSource dataSource = setupDataSource(cfgFileName);
- System.out.println("dataSource Done.");
- printDataSourceStats(dataSource);
- 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) {
- }
- try {
- if (stmt != null)
- stmt.close();
- } catch (Exception e) {
- }
- try {
- if (conn != null)
- conn.close();
- shutdownDataSource(dataSource);
- } catch (Exception e) {
- }
- }
- }
- /**
- * @param cfgFileName
- * @return DataSource
- */
- public static DataSource setupDataSource(String cfgFileName) {
- BasicDataSource ds = new BasicDataSource();
- try {
- Properties cfgpp = new Properties();
- cfgpp.load(DbcpDataSourceExample.class
- .getResourceAsStream(cfgFileName));
- ds.setDriverClassName(cfgpp.getProperty("jdbc.driverClassName"));
- ds.setUrl(cfgpp.getProperty("jdbc.url"));
- ds.setUsername(cfgpp.getProperty("jdbc.username"));
- ds.setPassword(cfgpp.getProperty("jdbc.password"));
- } catch (Exception e) {
- e.printStackTrace();
- return null;
- }
- return ds;
- }
- /**
- * @param ds
- */
- public static void printDataSourceStats(DataSource ds) {
- BasicDataSource bds = (BasicDataSource) ds;
- System.out.println("NumActive: " + bds.getNumActive());
- System.out.println("NumIdle: " + bds.getNumIdle());
- }
- /**
- * @param ds
- * @throws SQLException
- */
- public static void shutdownDataSource(DataSource ds) throws SQLException {
- BasicDataSource bds = (BasicDataSource) ds;
- bds.close();
- }
- }
运行结果:
引用
Setting up data source.
dataSource Done.
NumActive: 0
NumIdle: 0
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.
dataSource Done.
NumActive: 0
NumIdle: 0
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的应用测试
- <?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/dbcp/dbcp.jdbc.properties
- </value>
- </list>
- </property>
- </bean>
- <bean id="dbcpDataSource"
- class="org.apache.commons.dbcp.BasicDataSource"
- destroy-method="close">
- <property name="driverClassName"
- value="${jdbc.driverClassName}" />
- <property name="url" value="${jdbc.url}" />
- <property name="username" value="${jdbc.username}" />
- <property name="password" value="${jdbc.password}" />
- <property name="maxActive" value="20" />
- <property name="initialSize" value="1" />
- <property name="maxWait" value="60000" />
- <property name="maxIdle" value="15" />
- <property name="minIdle" value="5" />
- <property name="removeAbandoned" value="true" />
- <property name="removeAbandonedTimeout" value="180" />
- <property name="connectionProperties">
- <value>clientEncoding=utf-8</value>
- </property>
- </bean>
- </beans>
- package michael.jdbc.dbcp;
- import java.sql.Connection;
- import java.sql.ResultSet;
- import java.sql.SQLException;
- import java.sql.Statement;
- import javax.sql.DataSource;
- import org.apache.commons.dbcp.BasicDataSource;
- import org.springframework.context.ApplicationContext;
- import org.springframework.context.support.ClassPathXmlApplicationContext;
- /**
- * @see http://sjsky.iteye.com
- * @author michael sjsky007@gmail.com
- */
- public class DbcpSpringExample {
- /**
- * @param args
- */
- public static void main(String[] args) {
- System.out.println("spring xml init start ");
- ApplicationContext appCt = new ClassPathXmlApplicationContext(
- "michael/jdbc/dbcp/dbcp.ds.spring.xml");
- System.out.println("spring bean create DataSource");
- DataSource dataSource = (BasicDataSource) appCt
- .getBean("dbcpDataSource");
- 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) {
- }
- try {
- if (stmt != null)
- stmt.close();
- } catch (Exception e) {
- }
- try {
- if (conn != null)
- conn.close();
- } catch (Exception e) {
- }
- }
- }
- }
运行结果:
引用
spring xml init start
spring bean create DataSource
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.
spring bean create DataSource
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的应用测试
DBCP在Hibernate2中受支持,目前在hibernate3.0,已经不再支持dbcp了,hibernate的作者在hibernate.org中,明确指出在实践中发现dbcp有 BUG,在某些种情会产生很多空连接不能释放,所以推荐使用c3p0连接,本文重点只是描述其基本使用配置,不是比较两者的优劣,故不过多展开描述。
- <!DOCTYPE hibernate-configuration
- PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
- "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
- <hibernate-configuration>
- <session-factory>
- <!--database connection settings -->
- <property name="connection.driver_class">
- com.mysql.jdbc.Driver
- </property>
- <property name="connection.url">
- jdbc:mysql://localhost/iecms
- </property>
- <property name="connection.username">root</property>
- <property name="connection.password"></property>
- <!-- dbcp -->
- <!-- 连接池的最大活动个数 -->
- <property name="dbcp.maxActive">100</property>
- <!-- 当连接池中的连接已经被耗尽的时候,DBCP将怎样处理( 0 = 失败, 1 = 等待, 2= 增长) -->
- <property name="dbcp.whenExhaustedAction">1</property>
- <!-- 最大等待时间(ms) -->
- <property name="dbcp.maxWait">60000</property>
- <!-- 最大闲置的连接个数 -->
- <property name="dbcp.maxIdle">10</property>
- <!-- 下面是对 prepared statement -->
- <property name="dbcp.ps.maxActive">100</property>
- <property name="dbcp.ps.whenExhaustedAction">1</property>
- <property name="dbcp.ps.maxWait">60000</property>
- <property name="dbcp.ps.maxIdle">10</property>
- <property name="current_session_context_class">thread</property>
- <property name="show_sql">false</property>
- <property name="dialect">
- org.hibernate.dialect.MySQL5Dialect
- </property>
- <property name="hbm2ddl.auto">update</property>
- </session-factory>
- </hibernate-configuration>
- package michael.jdbc.dbcp;
- 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 sjsky007@gmail.com
- */
- public class DbcpHibernateExample {
- /**
- * @param args
- */
- public static void main(String[] args) {
- SessionFactory sessionFactory = null;
- try {
- System.out.println(" hibernate config start");
- Configuration config = new AnnotationConfiguration()
- .configure("michael/jdbc/dbcp/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:
引用
hibernate config start
create sessionFactory
create session
beginTransaction
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
create sessionFactory
create session
beginTransaction
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