OpenSessionInViewInterceptor (Spring Framework) - Spring Framework 1.2.9 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, HandlerInterceptor

public class OpenSessionInViewInterceptor
extends HibernateAccessor
implements HandlerInterceptor
extends HibernateAccessor
implements HandlerInterceptor

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

This interceptor works similar to the AOP HibernateInterceptor: It just makes Hibernate Sessions available via the thread. It is suitable for non-transactional execution but also for middle tier transactions via HibernateTransactionManager or JtaTransactionManager. In the latter case, Sessions pre-bound by this interceptor will automatically be used for the transactions and flushed accordingly.

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

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 if 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).

NOTE: This interceptor will by default not flush the Hibernate Session, as it assumes to be used in combination with business layer transactions that care for the flushing, or HibernateAccessors with flushMode FLUSH_EAGER. If you want this interceptor to flush after the handler has been invoked but before view rendering, set the flushMode of this interceptor to FLUSH_AUTO in such a scenario. Note that the flushMode of this interceptor will just apply in single session mode!

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(HttpServletRequest request, HttpServletResponse response, Object handler, 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 filtered.

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

void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)
          Flush the Hibernate Session before view rendering, if necessary.

boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
          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, 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(HttpServletRequest request, HttpServletResponse response, Object handler, 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 filtered.
`protected boolean`	`isSingleSession()` Return whether to use a single session for each request.
`void`	`postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)` Flush the Hibernate Session before view rendering, if necessary.
`boolean`	`preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)` 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, 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 boolean preHandle(HttpServletRequest request,
                         HttpServletResponse response,
                         Object handler)
                  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 HandlerInterceptor

Parameters:: request - current HTTP request; response - current HTTP response; handler - chosen handler to execute, for type and/or instance evaluation
Returns:: true if the execution chain should proceed with the next interceptor or the handler itself. Else, DispatcherServlet assumes that this interceptor has already dealt with the response itself.
Throws:: DataAccessException
See Also:: SessionFactoryUtils.getSession(org.hibernate.SessionFactory, boolean), TransactionSynchronizationManager

postHandle

public void postHandle(HttpServletRequest request,
                       HttpServletResponse response,
                       Object handler,
                       ModelAndView modelAndView)
                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 middle tier transactions have flushed their changes on commit.

Specified by:: postHandle in interface HandlerInterceptor

Parameters:: request - current HTTP request; response - current HTTP response; handler - chosen handler to execute, for type and/or instance examination; modelAndView - the ModelAndView that the handler returned (can also be null)
Throws:: DataAccessException
See Also:: HibernateAccessor.setFlushMode(int)

afterCompletion

public void afterCompletion(HttpServletRequest request,
                            HttpServletResponse response,
                            Object handler,
                            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 HandlerInterceptor

Parameters:: request - current HTTP request; response - current HTTP response; handler - chosen handler to execute, for type and/or instance examination; ex - exception thrown on handler execution, if any
Throws:: DataAccessException
See Also:: SessionFactoryUtils.releaseSession(org.hibernate.Session, org.hibernate.SessionFactory), TransactionSynchronizationManager

getParticipateAttributeName

protected String getParticipateAttributeName()

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

See Also:: PARTICIPATE_SUFFIX