我正在處理我的在線檔案存盤，今天我的 Netty TCP 檔案傳輸遇到了一些問題。所以問題是在客戶端的檔案中實際上只寫入了 8192 位元組的資料。我想知道問題是什么，以及如何解決它。
我已經看過所有其他 (5) 個 stackoverflow 問題。
這是我的服務器引導程式：
package com.martin.main;
import com.martin.file.*;
import com.martin.handler.*;
import com.martin.utils.*;
import io.netty.bootstrap.*;
import io.netty.channel.*;
import io.netty.channel.nio.*;
import io.netty.channel.socket.*;
import io.netty.channel.socket.nio.*;
import io.netty.handler.codec.*;
import java.io.*;
import java.net.*;
import java.util.*;
import java.util.concurrent.*;
public class Server {
public static void main(String[] args) {
new Server().setup(4783);
}
public ChannelFuture setup(int port) {
ChannelFuture future = null;
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
final ServerBootstrap bootstrap;
// OnlineFile.getOnlineFiles().add(new OnlineFile(737389, new File("C:\\Users\\marti\\Desktop\\filesharing\\testek.txt"), "ok.txt", (int) System.currentTimeMillis(), false, "C:\\Users\\marti\\Desktop\\filesharing\\testek.txt", false, null));
try {
bootstrap = new ServerBootstrap();
bootstrap.group(bossGroup, workerGroup);
bootstrap.channel(NioServerSocketChannel.class);
bootstrap.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
ChannelPipeline pipeline = socketChannel.pipeline();
//pipeline.addLast("framer", new LengthFieldBasedFrameDecoder());
pipeline.addLast("framer", new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4));
pipeline.addLast(new LengthFieldPrepender(4));
pipeline.addLast("login", new LoginServerHandler()); //the problem is not in that handler
}
});
future = bootstrap.bind(new InetSocketAddress(port)).sync().channel().closeFuture().sync();
}catch(InterruptedException e) {
e.printStackTrace();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
return future;
}
}
我的服務器處理程式：
public class ServerHandler extends ByteToMessageDecoder {
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
}
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf byteBuf, List<Object> list) throws Exception {
byte msgType = byteBuf.readByte();
if(FILEPACKETINFO == msgType) {
//The problem is probaly here
System.out.println("inide file req.");
int id = byteBuf.readInt();
for(OnlineFile onlineFile : OnlineFile.getOnlineFiles()) {
if(onlineFile.getId() == id) {
System.out.println("file request id: " id " actual id: " onlineFile.getId());
ByteBuf buf = Unpooled.buffer();
buf.writeByte(FILEPACKETINFO);
String fileName = onlineFile.getName();
File file = onlineFile.getActualFile();
buf.writeLong(file.length());
buf.writeInt(fileName.length());
buf.writeCharSequence(fileName, CharsetUtil.US_ASCII);
ctx.writeAndFlush(buf);
if(!(file.length() <= 0)) {
ctx.writeAndFlush(new ChunkedFile(file)).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture channelFuture) throws Exception {
System.out.println("written successfully!");
if (channelFuture.cause() != null) channelFuture.cause().printStackTrace();
}
});
} else {
System.out.println("length 0: " " (" file.length() ")");
}
}
}
} else if(REQUESTVISUALFILES == msgType) {
createAndSend(ctx); //send VISUAL files, problem not there
} else if(REQUESTFOLDERFILESBYID == msgType) {
int id = byteBuf.readInt();
createAndSend(ctx, id); //send VISUAL files by id, problem not there
}
}
我的客戶引導程式：
public static ChannelFuture setup(String host, int port) {
ChannelFuture channelFuture = null;
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group);
bootstrap.channel(NioSocketChannel.class);
bootstrap.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
ChannelPipeline pipeline = socketChannel.pipeline();
pipeline.addLast("framer", new LengthFieldBasedFrameDecoder(64*1024, 0, 4, 0, 4));
pipeline.addLast(lfp);
pipeline.addLast("login", new LoginHandler()); //the problem is not in that handler either
}
});
channelFuture = bootstrap.connect(new InetSocketAddress(host, port)).sync();
System.out.println("the setup came to an end!");
LoginForm.createAndShowGUI("Login");
mainChannel = channelFuture.channel();
channelFuture.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
group.shutdownGracefully();
}
return channelFuture;
}
}
我的客戶處理程式：
package com.martin.handler;
import io.netty.buffer.*;
import io.netty.channel.*;
import io.netty.util.*;
import java.io.*;
import java.nio.*;
import java.nio.channels.*;
public class FileChunkHandler extends SimpleChannelInboundHandler<ByteBuf> {
public static String currentFileName = "Test.txt";
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.pipeline().remove(this);
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf byteBuf) throws Exception {
//the problem is probably here
System.out.println("inside FileChunkHandler current file: " currentFileName);
ByteBuffer buffer = byteBuf.nioBuffer();
System.out.println(buffer.capacity() " buffer" " bytebuf: " byteBuf.readableBytes());
File file = triggerFileCreation();
// FileOutputStream fos = new FileOutputStream("C:\\Users\\marti\\storage\\" currentFileName);
RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");
FileChannel channel = randomAccessFile.getChannel();
while(buffer.hasRemaining()) {
channel.position(file.length());
channel.write(buffer);
System.out.println("chunk has just been written");
}
channel.close();
randomAccessFile.close();
//!!!--->IMPORTANT<-----!!!
ctx.pipeline().remove(this);
}
public static File triggerFileCreation() {
File file = new File(System.getProperty("user.home") "/storage/" currentFileName);
if(!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
return file;
}
}
編輯
問題是我太快地洗掉了處理程式，然后其他資料包在其他處理程式中處理/從管道中洗掉。
uj5u.com熱心網友回復：
問題確實很可能出在您的 FileChunkHandler 中。
您只讀取一個緩沖區（可能包含 8192 位元組 - 8kB），然后洗掉處理程式。剩余的塊要么被管道中的其他處理程式“處理”，要么到達管道的末端并被丟棄。如 Discord 中所述，您需要跟蹤預期的位元組數，減去收到的數字，并且只有當該數字達到 0 時，您才應該洗掉處理程式。
uj5u.com熱心網友回復：
一些代碼優化可以在這里完成
如果您要做的只是將資料從 ByteBuffer 傳輸到檔案，則替換此代碼
@Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf byteBuf) throws Exception {
//the problem is probably here
System.out.println("inside FileChunkHandler current file: " currentFileName);
ByteBuffer buffer = byteBuf.nioBuffer();
System.out.println(buffer.capacity() " buffer" " bytebuf: " byteBuf.readableBytes());
File file = triggerFileCreation();
// FileOutputStream fos = new FileOutputStream("C:\\Users\\marti\\storage\\" currentFileName);
RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");
FileChannel channel = randomAccessFile.getChannel();
while(buffer.hasRemaining()) {
channel.position(file.length());
channel.write(buffer);
System.out.println("chunk has just been written");
}
channel.close();
randomAccessFile.close();
//!!!--->IMPORTANT<-----!!!
ctx.pipeline().remove(this);
}
public static File triggerFileCreation() {
File file = new File(System.getProperty("user.home") "/storage/" currentFileName);
if(!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
return file;
}
有了這個
@Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf byteBuf) throws Exception
{
System.out.println("inside FileChunkHandler current file: " currentFileName);
ByteBuffer buffer = byteBuf.nioBuffer();
System.out.println(buffer.capacity() " buffer" " bytebuf: " byteBuf.readableBytes());
try(FileChannel channel=FileChannel.open(Path.of(System.getProperty("user.home"),"/storage/",currentFileName),StandardOpenOption.CREATE,StandardOpenOption.APPEND))
{
while(buffer.hasRemaining())
{
channel.write(buffer);
System.out.println("chunk has just been written");
}
}
//!!!--->IMPORTANT<-----!!!
ctx.pipeline().remove(this);
}
至于為什么你只能從服務器獲得 8KB 的位元組，我不確定。也許您的服務器重用了相同的 ByteBuffer，如果是這種情況，那么您必須在將其寫入檔案后清除它以使其 position=0 和 limit=buffer.capacity() 以便服務器可以使用新空間寫入更多位元組對它
而且由于您正在注冊一個處理程式以接收新塊，因此在檔案達到預期大小后洗掉處理程式可能是個好主意
將這兩者放在一起最終的代碼如下
@Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf byteBuf) throws Exception
{
System.out.println("inside FileChunkHandler current file: " currentFileName);
ByteBuffer buffer = byteBuf.nioBuffer();
System.out.println(buffer.capacity() " buffer" " bytebuf: " byteBuf.readableBytes());
try(FileChannel channel=FileChannel.open(Path.of(System.getProperty("user.home"),"/storage/",currentFileName),StandardOpenOption.CREATE,StandardOpenOption.APPEND))
{
while(buffer.hasRemaining())
{
channel.write(buffer);
System.out.println("chunk has just been written");
}
//clear the buffer so the server has space to transfer new chunks into it
buffer.clear();
//Remove handler only after file has reached an certain size
if(channel.size()>=expectedLength){
ctx.pipeline().remove(this);
}
}
}
除了代碼優化之外，其他的只是猜測，可能不是您要尋找的答案。如果有任何進展，請在下方評論
轉載請註明出處，本文鏈接：https://www.uj5u.com/qianduan/485466.html
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