3

我正在将 JavaEE/JPA 托管事务与 Oracle DB und Hibernate 一起使用，并且需要实现某种嵌套事务。据我所知，这种东西不支持开箱即用，但我应该能够为此目的使用保存点。

正如https://stackoverflow.com/a/7626387/173689所建议的，我尝试了以下方法：

@Transactional(value = TxType.REQUIRES_NEW)
public boolean doImport(Import importer, Row row) throws ImportRowFailedException {
    // stripped code ...
    // We need to try different possibilities from which one may succeed...
    // ...former failures must be rolled back!
    for (Possibility poss : importer.getPossibilities()) {
        if (this.tryPossibility(poss, row)) break;
    }
    // stripped code ...
}

public boolean tryPossibility(Possibility possibility, Row row) {
    try {
        Session session = this.em.unwrap(Session.class);
        session.doWork(new Work() {
            @Override
            public void execute(Connection connection) throws SQLException {
                Savepoint before = connection.setSavepoint();
                if (!possibility.importRow(row)) {
                    connection.rollback(before);
                    throw new ImportRowFailedException();
                }
            }
        });
    }
    catch (ImportRowFailedException ex) {
        return false;
    }
    return true;
}

当connection.rollback(before)我得到以下异常时：

Caused by: java.sql.SQLException: IJ031040: Connection is not associated with a managed connection: org.jboss.jca.adapters.jdbc.jdk8.WrappedConnectionJDK8@40a6a460
    at org.jboss.jca.adapters.jdbc.WrappedConnection.lock(WrappedConnection.java:164)
    at org.jboss.jca.adapters.jdbc.WrappedConnection.rollback(WrappedConnection.java:883)

我该如何处理？

4

2 回答 2

1

问题是大多数 JDBC 驱动程序并不真正支持嵌套事务。在您的情况下，您正在使用 JBoss，它提供了 JTA 事务管理器，但仍然依赖于ResoureManagerJDBC 提供程序提供的 XA，如本论坛主题中所述。

因此，您最好使用doReturningWork而不是doWork执行 SQL SAVEPOINT 命令，如下所示：

public boolean tryPossibility(Possibility possibility, Row row) {
    Session session = this.em.unwrap(Session.class);
    
    return session.doReturningWork(connection -> {
        connection.prepareStatement("SAVEPOINT IMPORT_ROW").executeUpdate();
        
        boolean importHasSuceed = possibility.importRow(row);
        
        if (!importHasSuceed) {
            connection.prepareStatement("ROLLBACK TO SAVEPOINT IMPORT_ROW").executeUpdate();
        }
        
        return importHasSuceed;
    });
}
于 2020-10-07T12:46:14.627 回答
1

最初java.sql.SQLException: IJ031040似乎与我们导入期间的特定结果有关。它后来被另一个java.sql.SQLException禁止回滚托管事务的方法替换。但我最终可以通过发出原生 SQL 语句来解决问题：

// Mark the current state as SAVEPOINT...
Session session = this.em.unwrap(Session.class);
session.doWork(new Work() {
    @Override
    public void execute(Connection connection) throws SQLException {
        connection.prepareStatement("SAVEPOINT TRY_POSSIBILITY").executeUpdate();
    }
});

// 
// Do all the risky changes... verify... decide...
// 

// Rollback to SAVEPOINT if necessary!
session.doWork(new Work() {
    @Override
    public void execute(Connection connection) throws SQLException {
        connection.prepareStatement("ROLLBACK TO SAVEPOINT TRY_POSSIBILITY").executeUpdate();
    }
});

这允许在较大的交易中进行“嵌套交易”并解决了我的问题。

于 2017-08-15T09:09:27.657 回答