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推荐公众号问题场景正文解决

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问题场景

首先已经按照官方推荐方式将Activiti与Spring事务整合在了一起，今天调整表结构之后开启流程抛出异常，业务代码回滚了；但是Activiti的数据没有回滚，回想起来这次做的流程比较简单没有出现异常，Acitiviti配置有之前做个流程引擎的搭建的，自己没有测过事务这块。

正文

刚开始是怀疑Acitivi事务并没有和Spring整合在一起，看了下官方配置没有毛病。然后debug开启流程源码，发现是直接提交到数据库中的，我看了下配置文件配置的auto-commit的确为false，百思不得其解。在翻日志的时候发现一个 AutoCommit 模式设置为“true”时，无法调用回滚操作 这个和配置文件中的不一致，悄悄翻看HikariDataSource源码(我公司用HikariDataSource号称性能最好的数据库连接池)。

调用的构造器 public HikariDataSource() { super(); fastPathPool = null; } /** 默认构造器 * Default constructor */ public HikariConfig() { dataSourceProperties = new Properties(); healthCheckProperties = new Properties(); 默认值 minIdle = -1; maxPoolSize = -1; maxLifetime = MAX_LIFETIME; connectionTimeout = CONNECTION_TIMEOUT; validationTimeout = VALIDATION_TIMEOUT; idleTimeout = IDLE_TIMEOUT; initializationFailTimeout = 1; 设置为了true isAutoCommit = true; 获取JVM系统变量 String systemProp = System.getProperty("hikaricp.configurationFile"); if (systemProp != null) { loadProperties(systemProp); } } 到这里只知道默认isAutoCommit为true，我们都知道数据库连接池维护的是一个线程池，到目前为止没有看到线程池信息，线程池的创建时在获取连接时进行的 public Connection getConnection() throws SQLException { if (isClosed()) { throw new SQLException("HikariDataSource " + this + " has been closed."); } if (fastPathPool != null) { return fastPathPool.getConnection(); } // See http://en.wikipedia.org/wiki/Double-checked_locking#Usage_in_Java HikariPool result = pool; if (result == null) { synchronized (this) { result = pool; 如果为null创建连接池 if (result == null) { validate(); LOGGER.info("{} - Starting...", getPoolName()); try { pool = result = new HikariPool(this); this.seal(); } catch (PoolInitializationException pie) { if (pie.getCause() instanceof SQLException) { throw (SQLException) pie.getCause(); } else { throw pie; } } LOGGER.info("{} - Start completed.", getPoolName()); } } } return result.getConnection(); } 创建连接池 public HikariPool(final HikariConfig config) { 设置连接池信息 super(config); this.connectionBag = new ConcurrentBag<>(this); this.suspendResumeLock = config.isAllowPoolSuspension() ? new SuspendResumeLock() : SuspendResumeLock.FAUX_LOCK; this.houseKeepingExecutorService = initializeHouseKeepingExecutorService(); checkFailFast(); if (config.getMetricsTrackerFactory() != null) { setMetricsTrackerFactory(config.getMetricsTrackerFactory()); } else { setMetricRegistry(config.getMetricRegistry()); } setHealthCheckRegistry(config.getHealthCheckRegistry()); registerMBeans(this); ThreadFactory threadFactory = config.getThreadFactory(); LinkedBlockingQueue<Runnable> addConnectionQueue = new LinkedBlockingQueue<>(config.getMaximumPoolSize()); this.addConnectionQueue = unmodifiableCollection(addConnectionQueue); this.addConnectionExecutor = createThreadPoolExecutor(addConnectionQueue, poolName + " connection adder", threadFactory, new ThreadPoolExecutor.DiscardPolicy()); this.closeConnectionExecutor = createThreadPoolExecutor(config.getMaximumPoolSize(), poolName + " connection closer", threadFactory, new ThreadPoolExecutor.CallerRunsPolicy()); this.leakTaskFactory = new ProxyLeakTaskFactory(config.getLeakDetectionThreshold(), houseKeepingExecutorService); this.houseKeeperTask = houseKeepingExecutorService.scheduleWithFixedDelay(new HouseKeeper(), 100L, HOUSEKEEPING_PERIOD_MS, MILLISECONDS); if (Boolean.getBoolean("com.zaxxer.hikari.blockUntilFilled") && config.getInitializationFailTimeout() > 1) { final long startTime = currentTime(); while (elapsedMillis(startTime) < config.getInitializationFailTimeout() && getTotalConnections() < config.getMinimumIdle()) { quietlySleep(MILLISECONDS.toMillis(100)); } } } PoolBase(final HikariConfig config) { this.config = config; this.networkTimeout = UNINITIALIZED; this.catalog = config.getCatalog(); this.schema = config.getSchema(); this.isReadOnly = config.isReadOnly(); 可以看到还是config中的值 this.isAutoCommit = config.isAutoCommit(); this.transactionIsolation = UtilityElf.getTransactionIsolation(config.getTransactionIsolation()); this.isQueryTimeoutSupported = UNINITIALIZED; this.isNetworkTimeoutSupported = UNINITIALIZED; this.isUseJdbc4Validation = config.getConnectionTestQuery() == null; this.isIsolateInternalQueries = config.isIsolateInternalQueries(); this.poolName = config.getPoolName(); this.connectionTimeout = config.getConnectionTimeout(); this.validationTimeout = config.getValidationTimeout(); this.lastConnectionFailure = new AtomicReference<>(); initializeDataSource(); } 到这里发现配置文件中auto-commit配置了没有用，因为它根本就不读，那么jdbcurl和 username，password怎么读的呢，是初始化database时读的，由于现在我们项目有两个数 据源，所以重写了平时业务需要的DataSource和JdbcTemplete @Bean @Primary @ConfigurationProperties(prefix = "spring.datasource") public DataSource dataSource(DataSourceProperties properties) { return DataSourceBuilder.create(properties.getClassLoader()) .type(HikariDataSource.class) .url(properties.determineUrl()) .username(properties.determineUsername()) .password(properties.determinePassword()) .build(); } @Bean @Primary public JdbcTemplate jdbcTemplate(DataSourceProperties properties) { return new JdbcTemplate(dataSource(properties)); } **为什么auto-commit默认为true** 问了大牛之后这样说:auto-commit设置为true是为了保护那些不受事务管理的sql，如果有需要将获取到的连接设置为false，执行之后设置为true。Spring的事物管理就是这样设置的

解决

public class SpringManagedTransaction implements Transaction { private static final Logger LOGGER = LoggerFactory.getLogger(SpringManagedTransaction.class); private final DataSource dataSource; private Connection connection; private boolean isConnectionTransactional; private boolean autoCommit; public SpringManagedTransaction(DataSource dataSource) { notNull(dataSource, "No DataSource specified"); this.dataSource = dataSource; } /** * {@inheritDoc} */ @Override public Connection getConnection() throws SQLException { if (this.connection == null) { openConnection(); } return this.connection; } /** * Gets a connection from Spring transaction manager and discovers if this {@code Transaction} should manage * connection or let it to Spring. * <p> * It also reads autocommit setting because when using Spring Transaction MyBatis thinks that autocommit is always * false and will always call commit/rollback so we need to no-op that calls. */ private void openConnection() throws SQLException { this.connection = DataSourceUtils.getConnection(this.dataSource); this.connection.setAutoCommit(false); // this.autoCommit = false; this.isConnectionTransactional = DataSourceUtils.isConnectionTransactional(this.connection, this.dataSource); LOGGER.debug( "JDBC Connection [" + this.connection + "] 将" + (this.isConnectionTransactional ? " " : " not ") + "会被Spring管理"); } /** * {@inheritDoc} */ @Override public void commit() throws SQLException { if (this.connection != null && !this.isConnectionTransactional && !this.autoCommit) { LOGGER.debug( "提交jdbc连接 [" + this.connection + "]"); this.connection.commit(); } } /** * {@inheritDoc} */ @Override public void rollback() throws SQLException { if (this.connection != null && !this.isConnectionTransactional && !this.autoCommit) { LOGGER.debug("回滚jdbc连接 [" + this.connection + "]"); this.connection.rollback(); } } /** * {@inheritDoc} */ @Override public void close() { LOGGER.debug("关闭jdbc连接 [" + this.connection + "]"); this.connection.setAutoCommit(true); DataSourceUtils.releaseConnection(this.connection, this.dataSource); } /** * {@inheritDoc} */ @Override public Integer getTimeout() { ConnectionHolder holder = (ConnectionHolder) TransactionSynchronizationManager.getResource(dataSource); if (holder != null && holder.hasTimeout()) { return holder.getTimeToLiveInSeconds(); } return null; } } public class SpringManagedTransactionFactory implements TransactionFactory { /** * {@inheritDoc} */ @Override public Transaction newTransaction(DataSource dataSource, TransactionIsolationLevel level, boolean autoCommit) { return new SpringManagedTransaction(dataSource); } /** * {@inheritDoc} */ @Override public Transaction newTransaction(Connection conn) { throw new UnsupportedOperationException("New Spring transactions require a DataSource"); } /** * {@inheritDoc} */ @Override public void setProperties(Properties props) { // not needed in this version } } @Configuration public class ActivitiConfig extends AbstractProcessEngineAutoConfiguration implements ProcessEngineConfigurationConfigurer { @Autowired private ActivitiUserTaskListener activitiUserTaskListener; @Override public void configure(SpringProcessEngineConfiguration processEngineConfiguration) { Map<String, List<ActivitiEventListener>> eventListeners = new HashMap<>(); eventListeners.put(ActivitiEventType.TASK_CREATED + "," + ActivitiEventType.TASK_COMPLETED, Arrays.asList(activitiUserTaskListener)); processEngineConfiguration.setTypedEventListeners(eventListeners); processEngineConfiguration.setTransactionFactory(new SpringManagedTransactionFactory()); } }