OpenSessionInViewInterceptor (Spring Framework API 2.1) - Spring Framework 2.1.0 API 文档英文版

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org.springframework.orm.hibernate3.support
Class OpenSessionInViewInterceptor

java.lang.Object
  org.springframework.orm.hibernate3.HibernateAccessor
      org.springframework.orm.hibernate3.support.OpenSessionInViewInterceptor

All Implemented Interfaces:: BeanFactoryAware, InitializingBean, WebRequestInterceptor

public class OpenSessionInViewInterceptor
extends HibernateAccessor
implements WebRequestInterceptor
extends HibernateAccessor
implements WebRequestInterceptor

Spring web request interceptor that binds a Hibernate Session to the thread for the entire processing of the request. Intended for the "Open Session in View" pattern, that is, to allow for lazy loading in web views despite the original transactions already being completed.

This interceptor makes Hibernate Sessions available via the current thread, which will be autodetected by transaction managers. It is suitable for service layer transactions via HibernateTransactionManager or JtaTransactionManager as well as for non-transactional execution (if configured appropriately).

NOTE: This interceptor will by default not flush the Hibernate Session, with the flush mode set to FlushMode.NEVER. It assumes to be used in combination with service layer transactions that care for the flushing: The active transaction manager will temporarily change the flush mode to FlushMode.AUTO during a read-write transaction, with the flush mode reset to FlushMode.NEVER at the end of each transaction. If you intend to use this interceptor without transactions, consider changing the default flush mode (through the "flushMode" property).

In contrast to OpenSessionInViewFilter, this interceptor is set up in a Spring application context and can thus take advantage of bean wiring. It inherits common Hibernate configuration properties from HibernateAccessor, to be configured in a bean definition.

WARNING: Applying this interceptor to existing logic can cause issues that have not appeared before, through the use of a single Hibernate Session for the processing of an entire request. In particular, the reassociation of persistent objects with a Hibernate Session has to occur at the very beginning of request processing, to avoid clashes will already loaded instances of the same objects.

Alternatively, turn this interceptor into deferred close mode, by specifying "singleSession"="false": It will not use a single session per request then, but rather let each data access operation or transaction use its own session (like without Open Session in View). Each of those sessions will be registered for deferred close, though, actually processed at request completion.

A single session per request allows for most efficient first-level caching, but can cause side effects, for example on saveOrUpdate or when continuing after a rolled-back transaction. The deferred close strategy is as safe as no Open Session in View in that respect, while still allowing for lazy loading in views (but not providing a first-level cache for the entire request).

Since:: 1.2
Author:: Juergen Hoeller
See Also:: setSingleSession(boolean), HibernateAccessor.setFlushMode(int), OpenSessionInViewFilter, HibernateInterceptor, HibernateTransactionManager, SessionFactoryUtils.getSession(org.hibernate.SessionFactory, boolean), TransactionSynchronizationManager

Field Summary

static String PARTICIPATE_SUFFIX
          Suffix that gets appended to the SessionFactory toString representation for the "participate in existing session handling" request attribute.

Fields inherited from class org.springframework.orm.hibernate3.HibernateAccessor

FLUSH_ALWAYS, FLUSH_AUTO, FLUSH_COMMIT, FLUSH_EAGER, FLUSH_NEVER, logger

Constructor Summary

OpenSessionInViewInterceptor()
          Create a new OpenSessionInViewInterceptor, turning the default flushMode to FLUSH_NEVER.

Method Summary

void afterCompletion(WebRequest request, Exception ex)
          Unbind the Hibernate Session from the thread and closes it (in single session mode), or process deferred close for all sessions that have been opened during the current request (in deferred close mode).

protected String getParticipateAttributeName()
          Return the name of the request attribute that identifies that a request is already intercepted.

protected boolean isSingleSession()
          Return whether to use a single session for each request.

void postHandle(WebRequest request, ModelMap model)
          Flush the Hibernate Session before view rendering, if necessary.

void preHandle(WebRequest request)
          Open a new Hibernate Session according to the settings of this HibernateAccessor and binds in to the thread via TransactionSynchronizationManager.

void setSingleSession(boolean singleSession)
          Set whether to use a single session for each request.

Methods inherited from class org.springframework.orm.hibernate3.HibernateAccessor

afterPropertiesSet, applyFlushMode, convertHibernateAccessException, convertJdbcAccessException, convertJdbcAccessException, disableFilters, enableFilters, flushIfNecessary, getDefaultJdbcExceptionTranslator, getEntityInterceptor, getFilterNames, getFlushMode, getJdbcExceptionTranslator, getSessionFactory, setBeanFactory, setEntityInterceptor, setEntityInterceptorBeanName, setFilterName, setFilterNames, setFlushMode, setFlushModeName, setJdbcExceptionTranslator, setSessionFactory

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Summary
`static String`	`PARTICIPATE_SUFFIX` Suffix that gets appended to the SessionFactory toString representation for the "participate in existing session handling" request attribute.

Fields inherited from class org.springframework.orm.hibernate3.HibernateAccessor
`FLUSH_ALWAYS, FLUSH_AUTO, FLUSH_COMMIT, FLUSH_EAGER, FLUSH_NEVER, logger`

Constructor Summary
`OpenSessionInViewInterceptor()` Create a new OpenSessionInViewInterceptor, turning the default flushMode to FLUSH_NEVER.

Method Summary
`void`	`afterCompletion(WebRequest request, Exception ex)` Unbind the Hibernate Session from the thread and closes it (in single session mode), or process deferred close for all sessions that have been opened during the current request (in deferred close mode).
`protected String`	`getParticipateAttributeName()` Return the name of the request attribute that identifies that a request is already intercepted.
`protected boolean`	`isSingleSession()` Return whether to use a single session for each request.
`void`	`postHandle(WebRequest request, ModelMap model)` Flush the Hibernate Session before view rendering, if necessary.
`void`	`preHandle(WebRequest request)` Open a new Hibernate Session according to the settings of this HibernateAccessor and binds in to the thread via TransactionSynchronizationManager.
`void`	`setSingleSession(boolean singleSession)` Set whether to use a single session for each request.

Methods inherited from class org.springframework.orm.hibernate3.HibernateAccessor
`afterPropertiesSet, applyFlushMode, convertHibernateAccessException, convertJdbcAccessException, convertJdbcAccessException, disableFilters, enableFilters, flushIfNecessary, getDefaultJdbcExceptionTranslator, getEntityInterceptor, getFilterNames, getFlushMode, getJdbcExceptionTranslator, getSessionFactory, setBeanFactory, setEntityInterceptor, setEntityInterceptorBeanName, setFilterName, setFilterNames, setFlushMode, setFlushModeName, setJdbcExceptionTranslator, setSessionFactory`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

PARTICIPATE_SUFFIX

public static final String PARTICIPATE_SUFFIX

Suffix that gets appended to the SessionFactory toString representation for the "participate in existing session handling" request attribute.

See Also:: getParticipateAttributeName(), Constant Field Values

Constructor Detail

OpenSessionInViewInterceptor

public OpenSessionInViewInterceptor()

Create a new OpenSessionInViewInterceptor, turning the default flushMode to FLUSH_NEVER.

See Also:: HibernateAccessor.setFlushMode(int)

Method Detail

setSingleSession

public void setSingleSession(boolean singleSession)

Set whether to use a single session for each request. Default is "true".

If set to false, each data access operation or transaction will use its own session (like without Open Session in View). Each of those sessions will be registered for deferred close, though, actually processed at request completion.

See Also:: SessionFactoryUtils.initDeferredClose(org.hibernate.SessionFactory), SessionFactoryUtils.processDeferredClose(org.hibernate.SessionFactory)

isSingleSession

protected boolean isSingleSession()

Return whether to use a single session for each request.

preHandle

public void preHandle(WebRequest request)
               throws DataAccessException

Open a new Hibernate Session according to the settings of this HibernateAccessor and binds in to the thread via TransactionSynchronizationManager.

Specified by:: preHandle in interface WebRequestInterceptor

Parameters:: request - the current web request
Throws:: DataAccessException
See Also:: SessionFactoryUtils.getSession(org.hibernate.SessionFactory, boolean), TransactionSynchronizationManager

postHandle

public void postHandle(WebRequest request,
                       ModelMap model)
                throws DataAccessException

Flush the Hibernate Session before view rendering, if necessary. Note that this just applies in single session mode!

The default is FLUSH_NEVER to avoid this extra flushing, assuming that service layer transactions have flushed their changes on commit.

Specified by:: postHandle in interface WebRequestInterceptor

Parameters:: request - the current web request; model - the map of model objects that will be exposed to the view (may be null). Can be used to analyze the exposed model and/or to add further model attributes, if desired.
Throws:: DataAccessException
See Also:: HibernateAccessor.setFlushMode(int)

afterCompletion

public void afterCompletion(WebRequest request,
                            Exception ex)
                     throws DataAccessException

Unbind the Hibernate Session from the thread and closes it (in single session mode), or process deferred close for all sessions that have been opened during the current request (in deferred close mode).

Specified by:: afterCompletion in interface WebRequestInterceptor

Parameters:: request - the current web request; ex - exception thrown on handler execution, if any
Throws:: DataAccessException
See Also:: TransactionSynchronizationManager

getParticipateAttributeName

protected String getParticipateAttributeName()

Return the name of the request attribute that identifies that a request is already intercepted. Default implementation takes the toString representation of the SessionFactory instance and appends ".PARTICIPATE".

See Also:: PARTICIPATE_SUFFIX