hibernate提供org.hibernate.connection.ConnectionProvider獲取jdbc連線，ConnectionProvider實現類包括
DriverManagerConnectionProvider
DateSourceConnectionProvider
UserSuppliedConnectionProvider
C3P0ConnectionProvider,ProxoolConnectionProvider
簡要說說這些實現
DriverManagerConnectionProvider用List維護連線，當jvm呼叫finalize方法時，關閉掉集合中的所有連線，並清空集合
getConnection
如果集合中有,則拿到最新的那個連線；如果沒有，DriverManager獲取連線
closeConnection
如果集合中連線的數量已經等於配置中指定的poolSize，則關閉此連線；如果沒有則放入集合
下
DateSourceManagerConnectionProvider通過jndi查詢資料來源配置中的hibernate.jndi.class和hibernate.jndi.url用於初始化javax.naming.InitialContext常用jndi配置hibernate.connection.datasource指定資料來源的名稱
getConnection
通過javax.sql.DataSource,getConnection獲取
closeConnection
java.sql.Connection.close
C3P0ConnectionProvider使用c3p0實現的javax.sql.DataSourcec3p0
ProxoolConnectionProvider使用proxool實現proxool
UserSuppliedConnectionProvider使用者繼承此類實現自己的連線提供者
至於使用哪種，由org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider決定
newConnectionProvider描述如下
如果hibernate.connection.provider_class不為空，使用例項化後的類
如果發現hibernate.connection.datasource，使用DatesourceConnectionProvider
如果發現hibernate.c3p0.*,使用C3P0ConnectionProvider
如果發現hibernate.proxool，使用ProxoolConnectionProvider
如果發現hibernate.connection.url，使用DriverManagerConnectionProvider
否則，返回UserSuppliedConnectionProvider
//$Id: ConnectionProviderFactory.java 7541 2005-07-18 22:37:31Z epbernard $
package org.hibernate.connection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Properties;
import java.util.Set;
import java.util.Map;
import java.beans.Introspector;
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.HibernateException;
import org.hibernate.cfg.Environment;
import org.hibernate.util.ReflectHelper;
/**
* Instantiates a connection provider given either <tt>System</tt> properties or
* a <tt>java.util.Properties</tt> instance. The <tt>ConnectionProviderFactory</tt>
* first attempts to find a name of a <tt>ConnectionProvider</tt> subclass in the
* property <tt>hibernate.connection.provider_class</tt>. If missing, heuristics are used
* to choose either <tt>DriverManagerConnectionProvider</tt>,
* <tt>DatasourceConnectionProvider</tt>, <tt>C3P0ConnectionProvider</tt> or
* <tt>DBCPConnectionProvider</tt>.
* @see ConnectionProvider
* @author Gavin King
*/
public final class ConnectionProviderFactory {
private static final Log log = LogFactory.getLog(ConnectionProviderFactory.class);
/**
* Instantiate a <tt>ConnectionProvider</tt> using <tt>System</tt> properties.
* @return ConnectionProvider
* @throws HibernateException
*/
public static ConnectionProvider newConnectionProvider() throws HibernateException {
return newConnectionProvider( Environment.getProperties() );
}
/**
* Instantiate a <tt>ConnectionProvider</tt> using given properties.
* Method newConnectionProvider.
* @param properties hibernate <tt>SessionFactory</tt> properties
* @return ConnectionProvider
* @throws HibernateException
*/
public static ConnectionProvider newConnectionProvider(Properties properties) throws HibernateException {
return newConnectionProvider( properties, null );
}
/**
* Instantiate a <tt>ConnectionProvider</tt> using given properties.
* Method newConnectionProvider.
* @param properties hibernate <tt>SessionFactory</tt> properties
* @Param connectionProviderInjectionData object to be injected in the conenction provided
* @return ConnectionProvider
* @throws HibernateException
*/
public static ConnectionProvider newConnectionProvider(Properties properties, Map connectionProviderInjectionData) throws HibernateException {
ConnectionProvider connections;
String providerClass = properties.getProperty(Environment.CONNECTION_PROVIDER);
if ( providerClass!=null ) {
try {
log.info("Initializing connection provider: " + providerClass);
connections = (ConnectionProvider) ReflectHelper.classForName(providerClass).newInstance();
}
catch (Exception e) {
log.fatal("Could not instantiate connection provider", e);
throw new HibernateException("Could not instantiate connection provider: " + providerClass);
}
}
else if ( properties.getProperty(Environment.DATASOURCE)!=null ) {
connections = new DatasourceConnectionProvider();
}
else if ( properties.getProperty(Environment.C3P0_MAX_SIZE)!=null ) {
connections = new C3P0ConnectionProvider();
}
else if (
properties.getProperty(Environment.PROXOOL_XML)!=null ||
properties.getProperty(Environment.PROXOOL_PROPERTIES)!=null ||
properties.getProperty(Environment.PROXOOL_EXISTING_POOL)!=null
) {
connections = new ProxoolConnectionProvider();
}
else if ( properties.getProperty(Environment.URL)!=null ) {
connections = new DriverManagerConnectionProvider();
}
else {
connections = new UserSuppliedConnectionProvider();
}
if ( connectionProviderInjectionData != null && connectionProviderInjectionData.size() != 0 ) {
//inject the data
try {
BeanInfo info = Introspector.getBeanInfo( connections.getClass() );
PropertyDescriptor[] descritors = info.getPropertyDescriptors();
int size = descritors.length;
for (int index = 0 ; index < size ; index++) {
String propertyName = descritors[index].getName();
if ( connectionProviderInjectionData.containsKey( propertyName ) ) {
Method method = descritors[index].getWriteMethod();
method.invoke( connections, new Object[] { connectionProviderInjectionData.get( propertyName ) } );
}
}
}
catch (IntrospectionException e) {
throw new HibernateException("Unable to inject objects into the conenction provider", e);
}
catch (IllegalAccessException e) {
throw new HibernateException("Unable to inject objects into the conenction provider", e);
}
catch (InvocationTargetException e) {
throw new HibernateException("Unable to inject objects into the conenction provider", e);
}
}
connections.configure(properties);
return connections;
}
// cannot be instantiated
private ConnectionProviderFactory() { throw new UnsupportedOperationException(); }
/**
* Transform JDBC connection properties.
*
* Passed in the form <tt>hibernate.connection.*</tt> to the
* format accepted by <tt>DriverManager</tt> by triming the leading "<tt>hibernate.connection</tt>".
*/
public static Properties getConnectionProperties(Properties properties) {
Iterator iter = properties.keySet().iterator();
Properties result = new Properties();
while ( iter.hasNext() ) {
String prop = (String) iter.next();
if ( prop.indexOf(Environment.CONNECTION_PREFIX) > -1 && !SPECIAL_PROPERTIES.contains(prop) ) {
result.setProperty(
prop.substring( Environment.CONNECTION_PREFIX.length()+1 ),
properties.getProperty(prop)
);
}
}
String userName = properties.getProperty(Environment.USER);
if (userName!=null) result.setProperty( "user", userName );
return result;
}
private static final Set SPECIAL_PROPERTIES;
static {
SPECIAL_PROPERTIES = new HashSet();
SPECIAL_PROPERTIES.add(Environment.DATASOURCE);
SPECIAL_PROPERTIES.add(Environment.URL);
SPECIAL_PROPERTIES.add(Environment.CONNECTION_PROVIDER);
SPECIAL_PROPERTIES.add(Environment.POOL_SIZE);
SPECIAL_PROPERTIES.add(Environment.ISOLATION);
SPECIAL_PROPERTIES.add(Environment.DRIVER);
SPECIAL_PROPERTIES.add(Environment.USER);
}
}