How to use zero-copy technology in Java?

In Java, zero-copy technology can be implemented in two ways.

1. The NIO (New Input/Output) library allows for zero-copy technology with channels and buffers, making it possible to transfer data without copying.

FileChannel sourceChannel = new FileInputStream("sourceFile.txt").getChannel();
FileChannel destinationChannel = new FileOutputStream("destinationFile.txt").getChannel();

sourceChannel.transferTo(0, sourceChannel.size(), destinationChannel);

sourceChannel.close();
destinationChannel.close();

1. Memory mapped files allow files to be mapped directly into memory, enabling operations to be performed on the file without needing to copy data between memory and the file.

RandomAccessFile sourceFile = new RandomAccessFile("sourceFile.txt", "rw");
FileChannel sourceChannel = sourceFile.getChannel();
MappedByteBuffer sourceBuffer = sourceChannel.map(FileChannel.MapMode.READ_WRITE, 0, sourceChannel.size());

RandomAccessFile destinationFile = new RandomAccessFile("destinationFile.txt", "rw");
FileChannel destinationChannel = destinationFile.getChannel();
MappedByteBuffer destinationBuffer = destinationChannel.map(FileChannel.MapMode.READ_WRITE, 0, sourceChannel.size());

// 将数据从源Buffer复制到目标Buffer
destinationBuffer.put(sourceBuffer);

sourceChannel.close();
destinationChannel.close();

Both methods can achieve zero-copy technology in Java, the specific choice depends on the specific requirements and scenarios.