Question

我正在尝试使用DBUnit将我的数据库的全部内容（HSQLDB）导出到XML，并且我得到了我无法理解的空指针错误。我正在关注FAQ中的示例：

IDatabaseConnection xmlConnection = new DatabaseConnection(conn);
IDataSet allTables = xmlConnection.createDataSet();
XmlDataSet.write(allTables, new FileOutputStream(DATABASE_PATH + ".xml"));

最后一行发生空指针错误。 conn和DATABASE_PATH不为空，因为它们都被检查并在程序中稍后使用而没有问题（使用OpenCSV将数据库导出为CSV，这完全且完全按预期工作）。

堆栈跟踪如下：

org.dbunit.dataset.DataSetException: java.sql.SQLException: java.lang.NullPointerException java.lang.NullPointerException
    at org.dbunit.database.DatabaseDataSet.initialize(DatabaseDataSet.java:243)
    at org.dbunit.database.DatabaseDataSet.getTableNames(DatabaseDataSet.java:272)
    at org.dbunit.database.DatabaseDataSet.createIterator(DatabaseDataSet.java:258)
    at org.dbunit.dataset.AbstractDataSet.iterator(AbstractDataSet.java:189)
    at org.dbunit.dataset.stream.DataSetProducerAdapter.(DataSetProducerAdapter.java:63)
    at org.dbunit.dataset.xml.XmlDataSetWriter.write(XmlDataSetWriter.java:128)
    at org.dbunit.dataset.xml.XmlDataSet.write(XmlDataSet.java:104)
    at org.dbunit.dataset.xml.XmlDataSet.write(XmlDataSet.java:91)
    at pms.DatabaseExporter.exportToXML(DatabaseExporter.java:181)
    at pms.DatabaseExporter.main(DatabaseExporter.java:301)
Caused by: java.sql.SQLException: java.lang.NullPointerException java.lang.NullPointerException
    at org.hsqldb.jdbc.Util.sqlException(Util.java:224)
    at org.hsqldb.jdbc.JDBCStatement.fetchResult(JDBCStatement.java:1830)
    at org.hsqldb.jdbc.JDBCStatement.executeQuery(JDBCStatement.java:181)
    at org.hsqldb.jdbc.JDBCDatabaseMetaData.execute(JDBCDatabaseMetaData.java:6150)
    at org.hsqldb.jdbc.JDBCDatabaseMetaData.getTables(JDBCDatabaseMetaData.java:3170)
    at org.dbunit.database.DefaultMetadataHandler.getTables(DefaultMetadataHandler.java:137)
    at org.dbunit.database.DatabaseDataSet.initialize(DatabaseDataSet.java:199)
    ... 9 more
Caused by: org.hsqldb.HsqlException: java.lang.NullPointerException
    at org.hsqldb.error.Error.error(Error.java:108)
    at org.hsqldb.result.Result.newErrorResult(Result.java:1069)
    at org.hsqldb.StatementDMQL.execute(StatementDMQL.java:192)
    at org.hsqldb.Session.executeCompiledStatement(Session.java:1315)
    at org.hsqldb.Session.executeDirectStatement(Session.java:1206)
    at org.hsqldb.Session.execute(Session.java:990)
    at org.hsqldb.jdbc.JDBCStatement.fetchResult(JDBCStatement.java:1822)
    ... 14 more
Caused by: java.lang.NullPointerException
    at org.hsqldb.types.CharacterType.compare(CharacterType.java:418)
    at org.hsqldb.index.IndexAVL.compareRowForInsertOrDelete(IndexAVL.java:617)
    at org.hsqldb.index.IndexAVLMemory.insert(IndexAVLMemory.java:214)
    at org.hsqldb.persist.RowStoreAVL.indexRow(RowStoreAVL.java:171)
    at org.hsqldb.persist.RowStoreAVLHybridExtended.indexRow(RowStoreAVLHybridExtended.java:99)
    at org.hsqldb.Table.insertSys(Table.java:2625)
    at org.hsqldb.dbinfo.DatabaseInformationMain.SYSTEM_TABLES(DatabaseInformationMain.java:2353)
    at org.hsqldb.dbinfo.DatabaseInformationMain.generateTable(DatabaseInformationMain.java:348)
    at org.hsqldb.dbinfo.DatabaseInformationFull.generateTable(DatabaseInformationFull.java:379)
    at org.hsqldb.dbinfo.DatabaseInformationMain.setStore(DatabaseInformationMain.java:507)
    at org.hsqldb.persist.PersistentStoreCollectionSession.getStore(PersistentStoreCollectionSession.java:138)
    at org.hsqldb.Table.getRowStore(Table.java:2817)
    at org.hsqldb.RangeVariable$RangeIteratorMain.(RangeVariable.java:939)
    at org.hsqldb.RangeVariable$RangeIteratorMain.(RangeVariable.java:917)
    at org.hsqldb.RangeVariable.getIterator(RangeVariable.java:770)
    at org.hsqldb.QuerySpecification.buildResult(QuerySpecification.java:1293)
    at org.hsqldb.QuerySpecification.getSingleResult(QuerySpecification.java:1245)
    at org.hsqldb.QuerySpecification.getResult(QuerySpecification.java:1235)
    at org.hsqldb.StatementQuery.getResult(StatementQuery.java:66)
    at org.hsqldb.StatementDMQL.execute(StatementDMQL.java:190)
    ... 18 more

我在谷歌上搜索过，在导出过程中找不到与此类错误有关的任何内容。我不熟悉SQL或JDBC，所以我希望在堆栈跟踪中有足够的信息让更有知识的人告诉我出了什么问题。如果有一些其他库可以更好地满足我的需求，我没有问题切换...我唯一需要的是现在使用XML导出/导入，所以我没有使用DBUnit做任何其他事情。无论如何，如果有人能告诉我发生了什么问题，或者我应该使用别的东西，我真的很感激。

Answer 1

这是HSQLDB系统表创建的特定版本中的错误，最近发现并更正了该错误。您可以从http://hsqldb.org/support/

尝试更新的HSQLDB jar

使用DBUnit将HSQLDB导出到XML会导致空指针错误

1 个答案: