Jar投掷中嵌入的HSQLDB

Question

我在jar的资源目录中的fat-jar中嵌入了一个HSQLDB。当我的脚本试图访问数据库时，它抛出一个关于缺少.lck文件的错误。但是，我的印象是jar文件中的DB将始终以只读模式访问。

Caused by: org.hsqldb.HsqlException: Database lock acquisition failure: lockFile: org.hsqldb.persist.LockFile@18f6cf91[file =/mnt/c/ctakes/SparkCtakes/jar:file:/mnt/c/ctakes/SparkCtakes/lib/ctakes-assembly-4.0.1.jar!/resources/org/apache/ctakes/dictionary/lookup/fast/sno_rx_16ab/sno_rx_16ab.lck, exists=false, locked=false, valid=false, ] method: openRAF reason: java.io.FileNotFoundException: /mnt/c/ctakes/SparkCtakes/jar:file:/mnt/c/ctakes/SparkCtakes/lib/ctakes-assembly-4.0.1.jar!/resources/org/apache/ctakes/dictionary/lookup/fast/sno_rx_16ab/sno_rx_16ab.lck (No such file or directory)
        at org.hsqldb.error.Error.error(Unknown Source)
        at org.hsqldb.error.Error.error(Unknown Source)
        at org.hsqldb.persist.LockFile.newLockFileLock(Unknown Source)
        at org.hsqldb.persist.Logger.acquireLock(Unknown Source)
        at org.hsqldb.persist.Logger.open(Unknown Source)
        at org.hsqldb.Database.reopen(Unknown Source)
        at org.hsqldb.Database.open(Unknown Source)
        at org.hsqldb.DatabaseManager.getDatabase(Unknown Source)
        at org.hsqldb.DatabaseManager.newSession(Unknown Source)
        ... 112 more

我创建这个包含数据库资源的fat-jar的方法是将resources文件夹放在src/main/scala/resources中，然后使用sbt-assembly打包所有内容。

Answer 1

当只读数据库位于Jar文件中时，访问数据库的URL必须是res:类型的URL。

假设Jar中的顶级目录是org，则URL将如下所示：

jdbc:hsqldb:res:/org/apache/ctakes/dictionary/look‌​up/fast/sno_rx_16ab/‌​sno_rx_16ab