FileChannel
FileChannel is a component of Java's NIO (java.nio.channels) that provides a channel-based view of a file for reading, writing, and manipulating file data. It supports random access, selective locking, and memory-mapped I/O, making it suitable for large files or performance-sensitive applications. FileChannel is an abstract class that can be obtained either by opening a path with FileChannel.open(Path, OpenOption...) or by obtaining a channel from a file stream or a RandomAccessFile via getChannel().
A FileChannel can be opened with Path and a varargs set of OpenOption values such as READ,
- Position and size: You can query and adjust the channel’s current position and query its size,
- I/O operations: read and write transfer data between the channel and ByteBuffer(s). Transfer can also be
- Memory-mapped I/O: The map method allows creating a MappedByteBuffer by mapping a region of the file
- Locking: The lock and tryLock methods provide file-region locking through FileLock, enabling coordinated access across processes.
- Persistence: force(boolean) forces updates to be written to the storage device, with an option to include
FileChannel is typically blocking and may depend on the underlying filesystem. It is commonly used for
Related concepts include FileLock, ByteBuffer, MapMode, and RandomAccessFile.