schemacrawler java.lang.NullPointerException:无法检索目录

Question

我尝试在hsqldb 2.51和h2 2.x中使用schemacrawler，代码如下：

final LimitOptionsBuilder limit = LimitOptionsBuilder.builder()
    .includeSchemas(new IncludeAll())
    .includeTables(new IncludeAll());
final LoadOptionsBuilder load = LoadOptionsBuilder.builder()
    .withSchemaInfoLevel(SchemaInfoLevelBuilder.minimum());
final SchemaCrawlerOptions options = SchemaCrawlerOptionsBuilder.newSchemaCrawlerOptions()
    .withLimitOptions(limit.toOptions())
    .withLoadOptions(load.toOptions());
final Catalog catalog = SchemaCrawlerUtility.getCatalog(connection, options);
// throw NullPointerException
for (final schemacrawler.schema.Table t : catalog.getTables())
{
    //more code...
}

没有NullPointerException错误，我无法获得目录。我在类路径中有两个档案：

• schemacrawler-16.16.11.jar
• schemacrawler-hsqldb-16.16.11.jar

如果有人有主意..。

Answer 1

在更改了一些代码之后，我成功地得到了一些有用的东西.

new LoggingConfig(Level.ALL);
final LimitOptionsBuilder limit = LimitOptionsBuilder.builder()
    .includeSchemas(new IncludeAll())
    .includeTables(new IncludeAll());
final LoadOptionsBuilder load = LoadOptionsBuilder.builder()
    .withSchemaInfoLevel(SchemaInfoLevelBuilder.minimum());
final SchemaCrawlerOptions options = SchemaCrawlerOptionsBuilder.newSchemaCrawlerOptions()
    .withLimitOptions(limit.toOptions())
    .withLoadOptions(load.toOptions()); 
final SchemaRetrievalOptions retrieval = SchemaCrawlerUtility.matchSchemaRetrievalOptions(connection);
schemacrawler.crawl.SchemaCrawler crawler = new schemacrawler.crawl.SchemaCrawler(connection, retrieval, options);
final Catalog catalog = crawler.crawl();
for (final schemacrawler.schema.Table t : catalog.getTables())
    {
        //more code...
    }

然而，第一个代码总是给我同样的错误..。