问题描述
我有一个需要与一些特权运行，这意味着在加载时会显示警告信息的小程序。如果用户拒绝警告消息，我想重定向到一个错误页面，并解释发生了什么。有没有办法做到这一点？
我看着于具有定时器运行，在一定时间后重定向但是这并不准确，这将是很好赶上从弹出的反应吧。
如果用户拒绝警告下抛出异常：
java.lang.SecurityException异常：尝试打开沙盒罐[JAR文件]
作为一个可信库
唯一的例外是达到初始化函数之前抛出。
..extend that to add a JS function that cancels the timer, then call that JS from the applet, is about the best protection you can get.
A try/catch on security related matters can work for some JREs that load applet sand-boxed if the security prompt is refused, but other run-times (notably the Iced Tea JRE) will not load the applet at all if the security prompt is refused.
If the user can be guaranteed to have a 'Next Generation' - Plug-In 2 JRE (mentioned in the applet info. page), it is possible to the use the JNLP API in an embedded applet. The JNLP services provide access to the local disks for a sand-boxed app. See this demo of the JNLP file services.
But there is a slight hitch. There is no option to persist the path to the file chosen by the user. In this lesser security environment, the JRE does not provide a File but instead a JNLP API FileContents object. It will not provide a path and is not serializable. But if the user is willing to choose the file each run, it could be workable.
..and that reminds me. Perhaps a better alternative for launching trusted apps. is to offer a free-floating (applet or) frame using Java Web Start. If the user refuses, it never appears on-screen, but they can click the launch button again any time they like (to be prompted again).
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