问题描述
我认为我误解了FileChannel的锁定功能是如何工作的。
I think I'm misunderstanding how the FileChannel's locking features work.
我想对文件进行独占写锁定，但允许从任何进程读取。
I want to have an exclusive write lock on a file, but allow reads from any process.
在运行Java 7的Windows 7计算机上，我可以使FileChannel的锁定工作，但它会阻止来自其他进程的读取和写入。
On a Windows 7 machine running Java 7, I can get FileChannel's lock to work, but it prevents both reads and writes from other processes.
如何实现不允许写入但允许其他进程读取的文件锁？
How can I achieve a file lock that disallows writes but allows reads by other processes?
推荐答案
-
FileChannel.lock（）处理文件区域，而不是文件本身。 - 锁定可以要么共享（许多读者，没有作家）或独家（一个作家，没有读者）。
FileChannel.lock()deals with file regions, not with the file itself.- The lock can be either shared (many readers, no writers) or exclusive (one writer and no readers).
我想你正在寻找一个有点不同的功能 - 打开一个文件进行写入，同时允许其他进程打开它进行读取而不是写入。
I guess you are looking for a bit different feature - to open a file for writing while allowing other processes to open it for reading but not for writing.
这可以实现作者：Java 7 带有非标准开放选项的API：
This can be achieved by Java 7 FileChannel.open API with non-standard open option:
import static java.nio.file.StandardOpenOption.*;
import static com.sun.nio.file.ExtendedOpenOption.*;
...
Path path = FileSystems.getDefault().getPath("noshared.tmp");
FileChannel fc = FileChannel.open(path, CREATE, WRITE, NOSHARE_WRITE);
注意 ExtendedOpenOption.NOSHARE_WRITE 这是非Oracle JDK中存在标准选项。
Note ExtendedOpenOption.NOSHARE_WRITE which is a non-standard option existing in Oracle JDK.
这篇关于使用java FileChannel FileLock来防止文件写入但允许读取的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！