从 jar 文件中提取 dll

Question

从 jar 文件中提取 rxtxSerial.dll 时，它给出了此异常，

java.lang.NullPointerException
    at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:1383)
    at org.apache.commons.io.IOUtils.copy(IOUtils.java:1357)
    at weighmentdesk.Weighment.loadJarDll(Weighment.java:940)
    at weighmentdesk.Weighment$5.run(Weighment.java:569)
    at java.awt.event.InvocationEvent.dispatch(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$000(Unknown Source)
    at java.awt.EventQueue$1.run(Unknown Source)
    at java.awt.EventQueue$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown
Source)
        at java.awt.EventQueue.dispatchEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.run(Unknown Source)

我正在查找该文件

getClass().getResourceAsStream("resources\\rxtxSerial.dll")

是否有任何问题。如果没有，是否有任何替代解决方案将 dll 文件提取到系统根目录（system32）中。

提前致谢。

Answer 1

getClass().getResourceAsStream("resources\rxtxSerial.dll") 很可能返回 null
如果它位于 jar 文件的根目录中 try :

getClass().getResourceAsStream("/rxtxSerial.dll")

如果它位于名为 resources 的目录下 try :

getClass().getResourceAsStream("/resources/rxtxSerial.dll")

等等...