Java tutorial
/* * Copyright 2010-2012 The MyBatis Team * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.raycloud.cobarclient.mybatis.spring; import java.sql.SQLException; import org.apache.ibatis.exceptions.ExceptionFactory; import org.apache.ibatis.exceptions.PersistenceException; import org.apache.ibatis.executor.ErrorContext; import org.apache.ibatis.executor.Executor; import org.apache.ibatis.logging.Log; import org.apache.ibatis.logging.LogFactory; import org.apache.ibatis.mapping.Environment; import org.apache.ibatis.session.ExecutorType; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.defaults.DefaultSqlSession; import org.apache.ibatis.transaction.Transaction; import org.apache.ibatis.transaction.TransactionFactory; import org.mybatis.spring.SqlSessionHolder; import org.mybatis.spring.transaction.SpringManagedTransactionFactory; import org.springframework.dao.DataAccessException; import org.springframework.dao.TransientDataAccessResourceException; import org.springframework.dao.support.PersistenceExceptionTranslator; import org.springframework.jdbc.datasource.DataSourceUtils; import org.springframework.transaction.support.TransactionSynchronizationAdapter; import static org.springframework.transaction.support.TransactionSynchronizationManager.*; import static org.springframework.util.Assert.notNull; /** * Handles MyBatis SqlSession life cycle. It can register and get SqlSessions from * Spring {@code TransactionSynchronizationManager}. Also works if no transaction is active. * * @version $Id: SqlSessionUtils.java 4894 2012-03-12 10:12:09Z simone.tripodi $ */ public final class SqlSessionUtils { private static final Log logger = LogFactory.getLog(SqlSessionUtils.class); /** * This class can't be instantiated, exposes static utility methods only. */ private SqlSessionUtils() { // do nothing } /** * Creates a new MyBatis {@code SqlSession} from the {@code SqlSessionFactory} * provided as a parameter and using its {@code DataSource} and {@code ExecutorType} * * @param sessionFactory a MyBatis {@code SqlSessionFactory} to create new sessions * @return a MyBatis {@code SqlSession} * @throws TransientDataAccessResourceException if a transaction is active and the * {@code SqlSessionFactory} is not using a {@code SpringManagedTransactionFactory} */ public static SqlSession getSqlSession(SqlSessionFactory sessionFactory) { ExecutorType executorType = sessionFactory.getConfiguration().getDefaultExecutorType(); return getSqlSession(sessionFactory, executorType, null); } /** * Gets an SqlSession from Spring Transaction Manager or creates a new one if needed. * Tries to get a SqlSession out of current transaction. If there is not any, it creates a new one. * Then, it synchronizes the SqlSession with the transaction if Spring TX is active and * <code>SpringManagedTransactionFactory</code> is configured as a transaction manager. * * @param sessionFactory a MyBatis {@code SqlSessionFactory} to create new sessions * @param executorType The executor type of the SqlSession to create * @param exceptionTranslator Optional. Translates SqlSession.commit() exceptions to Spring exceptions. * @throws TransientDataAccessResourceException if a transaction is active and the * {@code SqlSessionFactory} is not using a {@code SpringManagedTransactionFactory} * @see SpringManagedTransactionFactory */ public static SqlSession getSqlSession(SqlSessionFactory sessionFactory, ExecutorType executorType, PersistenceExceptionTranslator exceptionTranslator) { notNull(sessionFactory, "No SqlSessionFactory specified"); notNull(executorType, "No ExecutorType specified"); SqlSessionHolder holder = (SqlSessionHolder) getResource(sessionFactory); if (holder != null && holder.isSynchronizedWithTransaction()) { if (holder.getExecutorType() != executorType) { throw new TransientDataAccessResourceException( "Cannot change the ExecutorType when there is an existing transaction"); } holder.requested(); if (logger.isDebugEnabled()) { logger.debug("Fetched SqlSession [" + holder.getSqlSession() + "] from current transaction"); } return holder.getSqlSession(); } if (logger.isDebugEnabled()) { logger.debug("Creating a new SqlSession"); } SqlSession session = sessionFactory.openSession(executorType); // Register session holder if synchronization is active (i.e. a Spring TX is active) // // Note: The DataSource used by the Environment should be synchronized with the // transaction either through DataSourceTxMgr or another tx synchronization. // Further assume that if an exception is thrown, whatever started the transaction will // handle closing / rolling back the Connection associated with the SqlSession. if (isSynchronizationActive()) { Environment environment = sessionFactory.getConfiguration().getEnvironment(); if (environment.getTransactionFactory() instanceof SpringManagedTransactionFactory) { if (logger.isDebugEnabled()) { logger.debug("Registering transaction synchronization for SqlSession [" + session + "]"); } holder = new SqlSessionHolder(session, executorType, exceptionTranslator); bindResource(sessionFactory, holder); registerSynchronization(new SqlSessionSynchronization(holder, sessionFactory)); holder.setSynchronizedWithTransaction(true); holder.requested(); } else { if (getResource(environment.getDataSource()) == null) { if (logger.isDebugEnabled()) { logger.debug("SqlSession [" + session + "] was not registered for synchronization because DataSource is not transactional"); } } else { throw new TransientDataAccessResourceException( "SqlSessionFactory must be using a SpringManagedTransactionFactory in order to use Spring transaction synchronization"); } } } else { if (logger.isDebugEnabled()) { logger.debug("SqlSession [" + session + "] was not registered for synchronization because synchronization is not active"); } } return session; } /** * Checks if {@code SqlSession} passed as an argument is managed by Spring {@code TransactionSynchronizationManager} * If it is not, it closes it, otherwise it just updates the reference counter and * lets Spring call the close callback when the managed transaction ends * * @param session * @param sessionFactory */ public static void closeSqlSession(SqlSession session, SqlSessionFactory sessionFactory) { notNull(session, "No SqlSession specified"); notNull(sessionFactory, "No SqlSessionFactory specified"); SqlSessionHolder holder = (SqlSessionHolder) getResource(sessionFactory); if ((holder != null) && (holder.getSqlSession() == session)) { if (logger.isDebugEnabled()) { logger.debug("Releasing transactional SqlSession [" + session + "]"); } holder.released(); } else { if (logger.isDebugEnabled()) { logger.debug("Closing non transactional SqlSession [" + session + "]"); } session.close(); } } /** * Returns if the {@code SqlSession} passed as an argument is being managed by Spring * * @param session a MyBatis SqlSession to check * @param sessionFactory the SqlSessionFactory which the SqlSession was built with * @return true if session is transactional, otherwise false */ public static boolean isSqlSessionTransactional(SqlSession session, SqlSessionFactory sessionFactory) { notNull(session, "No SqlSession specified"); notNull(sessionFactory, "No SqlSessionFactory specified"); SqlSessionHolder holder = (SqlSessionHolder) getResource(sessionFactory); return (holder != null) && (holder.getSqlSession() == session); } /** * Callback for cleaning up resources. It cleans TransactionSynchronizationManager and * also commits and closes the {@code SqlSession}. * It assumes that {@code Connection} life cycle will be managed by * {@code DataSourceTransactionManager} or {@code JtaTransactionManager} */ private static final class SqlSessionSynchronization extends TransactionSynchronizationAdapter { private final SqlSessionHolder holder; private final SqlSessionFactory sessionFactory; public SqlSessionSynchronization(SqlSessionHolder holder, SqlSessionFactory sessionFactory) { notNull(holder, "Parameter 'holder' must be not null"); notNull(sessionFactory, "Parameter 'sessionFactory' must be not null"); this.holder = holder; this.sessionFactory = sessionFactory; } /** * {@inheritDoc} */ @Override public int getOrder() { // order right before any Connection synchronization return DataSourceUtils.CONNECTION_SYNCHRONIZATION_ORDER - 1; } /** * {@inheritDoc} */ @Override public void suspend() { unbindResource(this.sessionFactory); } /** * {@inheritDoc} */ @Override public void resume() { bindResource(this.sessionFactory, this.holder); } /** * {@inheritDoc} */ @Override public void beforeCommit(boolean readOnly) { // Connection commit or rollback will be handled by ConnectionSynchronization or // DataSourceTransactionManager. // But, do cleanup the SqlSession / Executor, including flushing BATCH statements so // they are actually executed. // SpringManagedTransaction will no-op the commit over the jdbc connection if (isActualTransactionActive()) { try { if (logger.isDebugEnabled()) { logger.debug("Transaction synchronization committing SqlSession [" + this.holder.getSqlSession() + "]"); } this.holder.getSqlSession().commit(); } catch (PersistenceException p) { if (this.holder.getPersistenceExceptionTranslator() != null) { DataAccessException translated = this.holder.getPersistenceExceptionTranslator() .translateExceptionIfPossible(p); if (translated != null) { throw translated; } } throw p; } } } /** * {@inheritDoc} */ @Override public void afterCompletion(int status) { // unbind the SqlSession from tx synchronization // Note, assuming DefaultSqlSession, rollback is not needed because rollback on // SpringManagedTransaction will no-op anyway. In addition, closing the session cleans // up the same internal resources as rollback. if (!this.holder.isOpen()) { unbindResource(this.sessionFactory); try { if (logger.isDebugEnabled()) { logger.debug("Transaction synchronization closing SqlSession [" + this.holder.getSqlSession() + "]"); } this.holder.getSqlSession().close(); } finally { this.holder.reset(); } } } } public static SqlSession getSqlSession(SqlSessionFactory sessionFactory, ExecutorType executorType, PersistenceExceptionTranslator exceptionTranslator, Environment environment) { return getSqlSession(sessionFactory, executorType, exceptionTranslator, environment, null); } public static SqlSessionHolder currentSqlSessionHolder(SqlSessionFactory sessionFactory) { return (SqlSessionHolder) getResource(sessionFactory); } /** * Environment? * * @param sessionFactory * @param executorType * @param exceptionTranslator * @param environment * @return */ public static SqlSession getSqlSession(SqlSessionFactory sessionFactory, ExecutorType executorType, PersistenceExceptionTranslator exceptionTranslator, Environment environment, SqlSessionHolder holder) { notNull(sessionFactory, "No SqlSessionFactory specified"); notNull(executorType, "No ExecutorType specified"); holder = (holder == null) ? (SqlSessionHolder) getResource(sessionFactory) : holder; if (holder != null && holder.isSynchronizedWithTransaction()) { if (holder.getExecutorType() != executorType) { throw new TransientDataAccessResourceException( "Cannot change the ExecutorType when there is an existing transaction"); } holder.requested(); if (logger.isDebugEnabled()) { logger.debug("Fetched SqlSession [" + holder.getSqlSession() + "] from current transaction"); } return holder.getSqlSession(); } if (logger.isDebugEnabled()) { logger.debug("Creating a new SqlSession"); } SqlSession session = /**sessionFactory.openSession(executorType);**/ openSession(environment, sessionFactory, executorType); // Register session holder if synchronization is active (i.e. a Spring TX is active) // // Note: The DataSource used by the Environment should be synchronized with the // transaction either through DataSourceTxMgr or another tx synchronization. // Further assume that if an exception is thrown, whatever started the transaction will // handle closing / rolling back the Connection associated with the SqlSession. if (isSynchronizationActive()) { // Environment environment = sessionFactory.getConfiguration().getEnvironment(); if (environment.getTransactionFactory() instanceof SpringManagedTransactionFactory) { if (logger.isDebugEnabled()) { logger.debug("Registering transaction synchronization for SqlSession [" + session + "]"); } holder = new SqlSessionHolder(session, executorType, exceptionTranslator); bindResource(sessionFactory, holder); registerSynchronization(new SqlSessionSynchronization(holder, sessionFactory)); holder.setSynchronizedWithTransaction(true); holder.requested(); } else { if (getResource(environment.getDataSource()) == null) { if (logger.isDebugEnabled()) { logger.debug("SqlSession [" + session + "] was not registered for synchronization because DataSource is not transactional"); } } else { throw new TransientDataAccessResourceException( "SqlSessionFactory must be using a SpringManagedTransactionFactory in order to use Spring transaction synchronization"); } } } else { if (logger.isDebugEnabled()) { logger.debug("SqlSession [" + session + "] was not registered for synchronization because synchronization is not active"); } } return session; } /** * Environment? * * @param environment * @param sessionFactory * @param executorType * @return */ private static SqlSession openSession(Environment environment, SqlSessionFactory sessionFactory, ExecutorType executorType) { Transaction tx = null; try { final TransactionFactory transactionFactory = environment.getTransactionFactory(); tx = transactionFactory.newTransaction(environment.getDataSource(), null, false); final Executor executor = sessionFactory.getConfiguration().newExecutor(tx, executorType); return new DefaultSqlSession(sessionFactory.getConfiguration(), executor, false); } catch (Exception e) { closeTransaction(tx); // may have fetched a connection so lets call close() throw ExceptionFactory.wrapException("Error opening session. Cause: " + e, e); } finally { ErrorContext.instance().reset(); } } private static void closeTransaction(Transaction tx) { if (tx != null) { try { tx.close(); } catch (SQLException ignore) { // Intentionally ignore. Prefer previous error. } } } }