java - Java 中的 FileLock 在同一进程内或不同进程之间或两者之间跨多个线程是否安全？

Question

Java 中的 FileLock 在同一进程内或不同进程之间或两者之间的多个线程之间是否安全？

javadoc说:

File locks are held on behalf of the entire Java virtual machine. They are not suitable for controlling access to a file by multiple threads within the same virtual machine.

File-lock objects are safe for use by multiple concurrent threads.

我不太明白:这是否意味着 FileLock 在同一个进程内的多个线程、多个不同进程之间或两者之间是安全的？

Answer 1

再往下:

This file-locking API is intended to map directly to the native locking facility of the underlying operating system. Thus the locks held on a file should be visible to all programs that have access to the file, regardless of the language in which those programs are written.

这强烈表明它的目的是在不同进程之间使用。

这一行:

They are not suitable for controlling access to a file by multiple threads within the same virtual machine.

建议如果您有一个包含多个线程的进程，则不应使用它。在这种情况下，您可以改为使用 synchronized 部分或 ReadWriteLock。