Question

我正在尝试commitChanges，但是抓住了java.lang.NullPointerException。日志：

...  
INFO: --- transaction started.
авг 04, 2015 12:33:59 PM org.apache.cayenne.access.dbsync.CreateIfNoSchemaStrategy processSchemaUpdate
INFO: Full or partial schema detected, skipping tables creation
авг 04, 2015 12:33:59 PM org.apache.cayenne.log.CommonsJdbcEventLogger logQuery
INFO: SELECT NEXT_ID FROM AUTO_PK_SUPPORT WHERE TABLE_NAME = 'ARTIST'
авг 04, 2015 12:33:59 PM org.apache.cayenne.log.CommonsJdbcEventLogger logSelectCount
INFO: === returned 1 row. - took 16 ms.
авг 04, 2015 12:33:59 PM org.apache.cayenne.log.CommonsJdbcEventLogger logQueryError
INFO: *** error.
java.lang.NullPointerException
    at com.relx.jdbc.jdbc2.LinterStatementImpl.getUpdateCount(LinterStatementImpl.java:419)
    at org.apache.cayenne.access.jdbc.SQLTemplateAction.execute(SQLTemplateAction.java:190)
    at org.apache.cayenne.access.jdbc.SQLTemplateAction.performAction(SQLTemplateAction.java:124)
    at org.apache.cayenne.access.DataNodeQueryAction.runQuery(DataNodeQueryAction.java:87)
    at org.apache.cayenne.access.DataNode.performQueries(DataNode.java:280)
    at org.apache.cayenne.dba.JdbcPkGenerator.longPkFromDatabase(JdbcPkGenerator.java:310)
    at org.apache.cayenne.dba.JdbcPkGenerator.generatePk(JdbcPkGenerator.java:268)
    at org.apache.cayenne.access.DataDomainInsertBucket.createPermIds(DataDomainInsertBucket.java:171)
    at org.apache.cayenne.access.DataDomainInsertBucket.appendQueriesInternal(DataDomainInsertBucket.java:76)
    at org.apache.cayenne.access.DataDomainSyncBucket.appendQueries(DataDomainSyncBucket.java:78)
    at org.apache.cayenne.access.DataDomainFlushAction.preprocess(DataDomainFlushAction.java:188)
    at org.apache.cayenne.access.DataDomainFlushAction.flush(DataDomainFlushAction.java:144)
    at org.apache.cayenne.access.DataDomain.onSyncFlush(DataDomain.java:853)
    at org.apache.cayenne.access.DataDomain$2.transform(DataDomain.java:817)
    at org.apache.cayenne.access.DataDomain.runInTransaction(DataDomain.java:877)
    at org.apache.cayenne.access.DataDomain.onSyncNoFilters(DataDomain.java:814)
    at org.apache.cayenne.access.DataDomain$DataDomainSyncFilterChain.onSync(DataDomain.java:1031)
    at org.apache.cayenne.access.DataDomain.onSync(DataDomain.java:785)
    at org.apache.cayenne.access.DataContext.flushToParent(DataContext.java:817)
    at org.apache.cayenne.access.DataContext.commitChanges(DataContext.java:756)
    at CayenneTest2.main(CayenneTest2.java:61)

表AUTO_PK_SUPPORT已创建并填充了Apache Cayenne。为什么抛出异常？

Answer 1

从堆栈跟踪中，您正在使用Cayenne v.3.1。相关代码为here。 Cayenne SQLTemplateAction检查查询结果是否为ResultSet，答案是“否”，假设结果是更新计数。因此它尝试在第190行读取更新计数：

 int updateCount = statement.getUpdateCount();

不知何故，底层语句对象（LinterStatementImpl）对此并不满意。我无法访问Linter DB驱动程序的源代码，因此我不能说出究竟是什么问题，但驱动程序的行为与Cayenne预期的不同。

也许Linter足够特别保证自己的Cayenne DbAdapter（??）随意加入Cayenne dev邮件列表，讨论如何写一个。

Apache Cayenne：commitChanges时出现NullPointerException

1 个答案: