netty websocket传输图片代码

### 回答1：
要在 Netty 中使用 WebSocket 传输图片，需要执行以下步骤：

1. 创建 WebSocket 服务端和客户端。

2. 在服务端处理器中，当收到新的 WebSocket 连接请求时，调用 `Channel.pipeline().addLast(new HttpObjectAggregator(65536))` 方法将 HTTP 消息聚合器添加到处理器链中。

3. 在客户端处理器中，当收到 WebSocket 握手响应消息时，调用 `Channel.pipeline().addLast(new HttpObjectAggregator(65536))` 方法将 HTTP 消息聚合器添加到处理器链中。

4. 在服务端处理器中，当收到 WebSocket 文本消息时，调用 `String encoded = Base64.getEncoder().encodeToString(bytes);` 将图片转换为 base64 编码的字符串。

5. 在客户端处理器中，当收到 WebSocket 文本消息时，调用 `byte[] decoded = Base64.getDecoder().decode(encoded);` 将 base64 编码的字符串转换为图片。

以下是一个简单的示例代码：

// 服务端代码

public class WebSocketServer {
    public static void main(String[] args) throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
             .channel(NioServerSocketChannel.class)
             .childHandler(new WebSocketServerInitializer());

            Channel ch = b.bind(8888).sync().channel();
            ch.closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

class WebSocketServerInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    public void initChannel(Socket  

### 回答2：
Netty是一个异步事件驱动的网络编程框架，它提供了强大的网络通信能力。下面是使用Netty实现WebSocket传输图片的代码示例：

1. 创建WebSocket服务器：

EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
protected void initChannel(SocketChannel ch) {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new HttpServerCodec());
pipeline.addLast(new HttpObjectAggregator(65536));
pipeline.addLast(new WebSocketServerProtocolHandler("/ws"));
pipeline.addLast(new ImageWebSocketHandler());
}
})
.bind(8080).sync().channel().closeFuture().sync();

2. 处理WebSocket连接和数据传输的处理器：

public class ImageWebSocketHandler extends SimpleChannelInboundHandler<WebSocketFrame> {
protected void channelRead0(ChannelHandlerContext ctx, WebSocketFrame frame) {
if (frame instanceof BinaryWebSocketFrame) {
BinaryWebSocketFrame dataFrame = (BinaryWebSocketFrame) frame;
ByteBuf buf = dataFrame.content();
byte[] bytes = new byte[buf.readableBytes()];
buf.readBytes(bytes);
// 处理接收到的图片数据
// ...
}
}
}

3. 图片的发送端，通过WebSocket将图片数据发送给服务器：

EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group)
.channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
protected void initChannel(SocketChannel ch) {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new HttpClientCodec());
pipeline.addLast(new HttpObjectAggregator(65536));
pipeline.addLast(new WebSocketClientProtocolHandler(WebSocketClientHandshakerFactory.newHandshaker(URI.create("ws://localhost:8080/ws"), WebSocketVersion.V13, null, false, new DefaultHttpHeaders())));
pipeline.addLast(new ImageWebSocketClientHandler());
}
});
Channel channel = bootstrap.connect("localhost", 8080).sync().channel();

// 加载图片数据
byte[] imgData = loadImageData();

// 将图片数据发送给服务器
channel.writeAndFlush(new BinaryWebSocketFrame(Unpooled.wrappedBuffer(imgData))).sync();
} finally {
group.shutdownGracefully();
}

4. 图片的接收端，通过WebSocket接收服务器发送的图片数据：

public class ImageWebSocketClientHandler extends SimpleChannelInboundHandler<WebSocketFrame> {
protected void channelRead0(ChannelHandlerContext ctx, WebSocketFrame frame) {
if (frame instanceof BinaryWebSocketFrame) {
BinaryWebSocketFrame dataFrame = (BinaryWebSocketFrame) frame;
ByteBuf buf = dataFrame.content();
byte[] bytes = new byte[buf.readableBytes()];
buf.readBytes(bytes);
// 处理接收到的图片数据
// ...
}
}
}

上述代码示例演示了如何使用Netty实现WebSocket传输图片的功能。在服务器端，我们通过WebSocketServerProtocolHandler处理WebSocket连接，并在ImageWebSocketHandler中处理接收到的图片数据。在客户端，我们通过WebSocketClientProtocolHandler建立到服务器的WebSocket连接，并在ImageWebSocketClientHandler中处理接收到的图片数据。  

### 回答3：
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.*;
import io.netty.handler.stream.ChunkedFile;
import io.netty.handler.stream.ChunkedWriteHandler;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolConfig;
import io.netty.handler.codec.http.websocketx.WebSocketCloseStatus;

import java.io.File;
import java.io.FileInputStream;

public class WebSocketServer {

    public static void main(String[] args) throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new WebSocketServerInitializer());

            ChannelFuture future = bootstrap.bind(8080).sync();
            future.channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

class WebSocketServerInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();

        pipeline.addLast(new HttpServerCodec());
        pipeline.addLast(new HttpObjectAggregator(64 * 1024));
        pipeline.addLast(new ChunkedWriteHandler());
        pipeline.addLast(new WebSocketServerProtocolHandler("/websocket", null, true, 65536));

        pipeline.addLast(new WebSocketServerHandler());
    }
}

class WebSocketServerHandler extends SimpleChannelInboundHandler<WebSocketFrame> {
    private static final String IMAGE_PATH = "path/to/image.jpg";

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, WebSocketFrame frame) throws Exception {
        if (frame instanceof TextWebSocketFrame) {
            // 若收到的帧是文本类型，加入逻辑处理...
            TextWebSocketFrame textFrame = (TextWebSocketFrame) frame;

            // 示例：回传客户端收到的消息
            ctx.writeAndFlush(new TextWebSocketFrame("Server received message: " + textFrame.text()));
        } else if (frame instanceof BinaryWebSocketFrame) {
            // 若收到的帧是二进制类型，处理图片传输逻辑...
            BinaryWebSocketFrame binaryFrame = (BinaryWebSocketFrame) frame;

            // 读取本地图片文件
            File imageFile = new File(IMAGE_PATH);
            FileInputStream fis = new FileInputStream(imageFile);

            // 传输内容通过chunks进行分块
            ChunkedFile chunkedFile = new ChunkedFile(imageFile);

            // 将图片数据按块发送给客户端
            while (chunkedFile.isEndOfInput() == false) {
                ctx.writeAndFlush(new BinaryWebSocketFrame(chunkedFile.readChunk(ctx.alloc())));
            }

            // 关闭资源
            fis.close();
            chunkedFile.close();

            // 关闭websocket连接
            ctx.channel().close();

        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
    }
}