NIO-Based Zero Copy File Transfer Implementation

Server Side Implementation

package com.atguigu.nio.zerocopy;import java.io.IOException;import java.net.InetSocketAddress;import java.net.ServerSocket;import java.nio.ByteBuffer;import java.nio.channels.ServerSocketChannel;import java.nio.channels.SocketChannel;public class NewIOServer {    public static void main(String[] args) throws Exception {        InetSocketAddress address = new InetSocketAddress(7002);        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();        ServerSocket serverSocket = serverSocketChannel.socket();        serverSocket.bind(address);        ByteBuffer byteBuffer = ByteBuffer.allocate(4096);        while (true) {            SocketChannel socketChannel = serverSocketChannel.accept();            int readCount = 0;            while (-1 != readCount) {                try {                    readCount = socketChannel.read(byteBuffer);                } catch (Exception e) {                    break;                }                byteBuffer.rewind();            }        }    }}

Client Side Implementation

package com.atguigu.nio.zerocopy;import java.io.FileInputStream;import java.net.InetSocketAddress;import java.nio.channels.FileChannel;import java.nio.channels.SocketChannel;public class NewIOClient {    public static void main(String[] args) throws Exception {        SocketChannel socketChannel = SocketChannel.open();        socketChannel.connect(new InetSocketAddress("localhost", 7002));                String filename = "./test.avi";        FileChannel fileChannel = new FileInputStream(filename).getChannel();                long startTime = System.currentTimeMillis();        long totalSize = fileChannel.size();        long max_pkg = 8 * 1024 * 1024;        long cur_pos = 0;        long transSize = 0;                while (totalSize > max_pkg) {            long tmp = fileChannel.transferTo(cur_pos, max_pkg, socketChannel);            totalSize -= tmp;            cur_pos += tmp;            transSize += tmp;        }                if (totalSize > 0) {            long tmp = fileChannel.transferTo(cur_pos, totalSize, socketChannel);            transSize += tmp;        }                System.out.println("Total bytes transferred: " + transSize +                          " Elapsed time: " + (System.currentTimeMillis() - startTime));        fileChannel.close();    }}

Explanation

Server Side

Port Binding: The server binds to port 7002 using InetSocketAddress.

Reading Data: It uses a ByteBuffer of size 4096 to read data from connected clients.

Zero Copy Mechanism: The data is read directly from the socket channel into the buffer, leveraging zero copy functionality for efficient I/O operations.

Client Side

Connection Establishment: The client connects to the server at port 7002.

File Reading: It reads the file using FileInputStream and converts it to a FileChannel for NIO operations.

Zero Copy Transfer: The client transfers the file data to the server in chunks to handle large files efficiently. The transfer size is dynamically adjusted based on the maximum packet size (8MB in this implementation).