Question

我遇到的问题是数据库连接没有被发布＆＃39;由javers。

我们使用Hibernate 5.0.6，Hikari作为我们的连接池，MSSQL Server作为我们的数据库。 Javers配置如下（片段）：

JaversBuilder.javers().
    registerJaversRepository(SqlRepositoryBuilder.sqlRepository().
        withConnectionProvider(() -> ((SessionFactoryImpl) sessionFactory).getServiceRegistry().
            getService(org.hibernate.engine.jdbc.connections.spi.ConnectionProvider.class).getConnection()).
        withDialect(DialectName.MSSQL).
        build()).
    build();

获取连接的方式很好。如果没有可用的连接池，则连接池将打开数据库连接。然而，由javers获得的连接是“使用”。永远。

61366 [Hikari Housekeeping Timer (pool HikariPool-0)] DEBUG HikariPool  - Before cleanup pool stats HikariPool-0 (total=100, inUse=100, avail=0, waiting=1)
61366 [Hikari Housekeeping Timer (pool HikariPool-0)] DEBUG HikariPool  - After cleanup pool stats HikariPool-0 (total=100, inUse=100, avail=0, waiting=1)
61366 [HikariCP connection filler (pool HikariPool-0)] DEBUG HikariPool  - After fill pool stats HikariPool-0 (total=100, inUse=100, avail=0, waiting=1)

我是否必须手动关闭连接？如果我尝试这个（只关闭我在一秒钟后给Javers的每个连接），连接池就会被清除。但是，这种方法不是一种选择。

有什么我想念的吗？如果我必须手动关闭连接，是否至少可以收到Javers的通知，它不再需要连接？

Answer 1

你不应该关闭连接，事实上你也不应该为JaVers打开新的连接。

主要想法是JaVers 重用连接和应用程序打开和关闭的事务。

示例场景：

应用程序从池中获取连接
应用程序执行一些DML操作，例如插入新人＃1
JaVers借用app的连接并插入Person＃1的审核记录
应用程序提交（或回滚）事务并返回与池的连接

如果您使用的是JPA API，则可以使用与JaVers捆绑在一起的JpaHibernateConnectionProvider：

package org.javers.spring.jpa;
... //

public class JpaHibernateConnectionProvider implements ConnectionProvider{

    @PersistenceContext
    private EntityManager entityManager;

    @Override
    public Connection getConnection() {

        SessionImpl session =  (SessionImpl)entityManager.unwrap(Session.class);

        return session.connection();
    }
}

如果你使用裸Hibernate，你可以编写类似的代码，它从当前的Hibernate会话（有界到当前线程）中提取连接。

Answer 2

好的，这是我的解决方案。收集Javers获得的所有连接并关闭它们（close（）不会关闭但是将它们释放到连接池！）在Javers完成工作之后：

收集连接的类：

public class ConnectionCleanup {

    private static final Logger LOG = LoggerFactory.getLogger(ConnectionCleanup.class);
    private static final ThreadLocal<List<Connection>> connections = new ThreadLocal<>();

    public static void add(final Connection connection) {
        List<Connection> listConnections = connections.get();
        if (listConnections == null) {
            listConnections = new ArrayList<>();
            connections.set(listConnections);
        }
        listConnections.add(connection);
    }

    public static void cleanup() {
        final List<Connection> listConnections = connections.get();
        if (listConnections == null) {
            return;
        }
        for (final Connection con : listConnections) {
            try {
                if (!con.isClosed()) {
                    con.close();
                }
            } catch (final Exception ex) {
                LOG.error("Caught an", ex);
            }
        }
        connections.set(null);
    }
}

在Javers工作完成后包装SqlRepository以调用cleanup：

public class CleanupJaversSqlRepository implements JaversRepository {

    private final JaversSqlRepository repository;

    public CleanupJaversSqlRepository(final JaversSqlRepository repository) {
        this.repository = repository;
    }

    @Override
    public Optional<CdoSnapshot> getLatest(final GlobalId globalId) {
        final Optional<CdoSnapshot> latest = repository.getLatest(globalId);
        ConnectionCleanup.cleanup();
        return latest;
    }

    @Override
    public void persist(final Commit commit) {
        repository.persist(commit);
        ConnectionCleanup.cleanup();
    }

    @Override
    public CommitId getHeadId() {
        final CommitId commitId = repository.getHeadId();
        ConnectionCleanup.cleanup();
        return commitId;
    }

    @Override
    public void setJsonConverter(final JsonConverter jsonConverter) {
        repository.setJsonConverter(jsonConverter);
        ConnectionCleanup.cleanup();
    }

    @Override
    public void ensureSchema() {
        repository.ensureSchema();
        ConnectionCleanup.cleanup();
    }

    @Override
    public List<CdoSnapshot> getStateHistory(
            final GlobalId globalId,
            final QueryParams queryParams) {
        final List<CdoSnapshot> stateHistory = repository.getStateHistory(globalId, queryParams);
        ConnectionCleanup.cleanup();
        return stateHistory;
    }

    @Override
    public List<CdoSnapshot> getPropertyStateHistory(
            final GlobalId globalId,
            final String propertyName,
            final QueryParams queryParams) {
        final List<CdoSnapshot> stateHistory = repository.getPropertyStateHistory(
                globalId, propertyName, queryParams);
        ConnectionCleanup.cleanup();
        return stateHistory;
    }

    @Override
    public List<CdoSnapshot> getStateHistory(
            final ManagedType givenClass,
            final QueryParams queryParams) {
        final List<CdoSnapshot> stateHistory = repository.getStateHistory(givenClass, queryParams);
        ConnectionCleanup.cleanup();
        return stateHistory;
    }

    @Override
    public List<CdoSnapshot> getPropertyStateHistory(
            final ManagedType givenClass,
            final String propertyName,
            final QueryParams queryParams) {
        final List<CdoSnapshot> stateHistory = repository.getPropertyStateHistory(
                givenClass, propertyName, queryParams);
        ConnectionCleanup.cleanup();
        return stateHistory;
    }

    @Override
    public List<CdoSnapshot> getValueObjectStateHistory(
            final EntityType ownerEntity,
            final String path,
            final QueryParams queryParams) {
        final List<CdoSnapshot> stateHistory = repository.getValueObjectStateHistory(
                ownerEntity, path, queryParams);
        ConnectionCleanup.cleanup();
        return stateHistory;
    }
}

最后，把它们放在一起：

JaversBuilder.javers().
                registerJaversRepository(new CleanupJaversSqlRepository(SqlRepositoryBuilder.sqlRepository().
                        withConnectionProvider(() -> {
                            final Connection connection = ((SessionFactoryImpl) sessionFactory).
                                    getServiceRegistry().getService(
                                            org.hibernate.engine.jdbc.connections.spi.ConnectionProvider.class).
                                    getConnection();
                            ConnectionCleanup.add(connection);
                            return connection;
                        }).
                        withDialect(DialectName.MSSQL).
                        build())).
                build();

Javers SQL连接永远在使用中

2 个答案: