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最近、私のプロジェクトでnettyを使用し始めました。私は、Nettyがどのように動作するかを理解するために、HexDumpProxyの例を実装しました。私はStringDecoderとStringEncoderをチャネルパイプラインに追加してパイプラインが壊れてしまうという問題に直面しています。デコーダ/エンコーダが存在しない場合、プログラムは正常に機能します。誰かが私に説明することができますなぜこれが起こるのですか？どんな助けも高く評価されます！デコーダ/エンコーダを追加するとNettyパイプラインが壊れる
次のコードを追加しています。
メインクラス：
public final class HexDumpProxy {
public static void main(String[] args) throws Exception {
// Configure the bootstrap.
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.handler(new LoggingHandler(LogLevel.INFO))
.childHandler(new HexDumpProxyInitializer("127.0.0.1", 9000))
.childOption(ChannelOption.AUTO_READ, false)
.bind(8000).sync().channel().closeFuture().sync();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
イニシャライザクラス：
public class HexDumpProxyInitializer extends ChannelInitializer<SocketChannel> {
private final String remoteHost;
private final int remotePort;
public HexDumpProxyInitializer (String remoteHost, int remotePort) {
this.remoteHost = remoteHost;
this.remotePort = remotePort;
}
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast("frameDecoder", new LineBasedFrameDecoder(80));
ch.pipeline().addLast("decoder", new StringDecoder());
ch.pipeline().addLast("encoder", new StringEncoder());
//ch.pipeline().addLast(new LoggingHandler(LogLevel.INFO));
ch.pipeline().addLast(new HexDumpProxyFrontendHandler(remoteHost, remotePort));
}
}
フロントエンドHandlerクラス：
public class HexDumpProxyFrontendHandler extends ChannelInboundHandlerAdapter {
private final String remoteHost;
private final int remotePort;
private Channel serverChannel;
public HexDumpProxyFrontendHandler(String remoteHost, int remotePort) {
this.remoteHost = remoteHost;
this.remotePort = remotePort;
}
@Override
public void channelActive(ChannelHandlerContext ctx) {
final Channel clientChannel = ctx.channel();
Bootstrap b = new Bootstrap();
b.group(clientChannel.eventLoop())
.channel(ctx.channel().getClass())
.handler(new HexDumpProxyBackendHandler(clientChannel))
.option(ChannelOption.AUTO_READ, false);
ChannelFuture f = b.connect(remoteHost, remotePort);
serverChannel = f.channel();
f.addListener(new ChannelFutureListener() {
public void operationComplete(ChannelFuture future) {
if (future.isSuccess()) {
clientChannel.read();
}
else
clientChannel.close();
}
});
}
@Override
public void channelRead (final ChannelHandlerContext ctx, Object msg) {
if (serverChannel.isActive()) {
System.out.println("************" + msg);
serverChannel.writeAndFlush(msg).addListener(new ChannelFutureListener() {
public void operationComplete(ChannelFuture future) {
if (future.isSuccess()) {
ctx.channel().read();
System.out.println("Read from server channel. - channelRead");
} else {
future.channel().close();
System.out.println("Close server channel.");
}
}
});
}
}
@Override
public void channelInactive (ChannelHandlerContext ctx) {
if (serverChannel != null) {
closeOnFlush(serverChannel);
System.out.println("close on flush - server channel");
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
static void closeOnFlush (Channel ch) {
if (ch.isActive())
ch.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
ctx.channel().read();
}
}
バックエンドHandlerクラス：
public class HexDumpProxyBackendHandler extends ChannelInboundHandlerAdapter {
private final Channel clientChannel;
public HexDumpProxyBackendHandler (Channel clientChannel) {
this.clientChannel = clientChannel;
}
@Override
public void channelActive (ChannelHandlerContext ctx) {
ctx.channel().read();
System.out.println("Read from client channel. - channelActive");
}
@Override
public void channelRead (final ChannelHandlerContext ctx, Object msg) {
System.out.println("~~~~~~~~~~~" + msg);
clientChannel.writeAndFlush(msg).addListener(new ChannelFutureListener() {
public void operationComplete(ChannelFuture future) {
if (future.isSuccess()) {
clientChannel.read();
System.out.println("Read from client channel. - channelRead");
} else {
clientChannel.close();
System.out.println("Close client channel.");
}
}
});
}
@Override
public void channelInactive (ChannelHandlerContext ctx) {
HexDumpProxyFrontendHandler.closeOnFlush(clientChannel);
System.out.println("close on flush - client channel");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
ctx.channel().read();
}
}