netty 的ByteBuf 到达2048后不自动扩容,怎么办?

Question

public class ChatCodec extends ByteToMessageCodec<ChatMessage> {

    @Override
    protected void encode(ChannelHandlerContext channelHandlerContext, ChatMessage chatMessage, ByteBuf out) throws Exception {
        System.out.println("开始编码");
        out.writeInt(chatMessage.getMagic());
        out.writeByte(chatMessage.getVersion());
        out.writeByte(chatMessage.getType());
        out.writeByte(chatMessage.getCharset());
        if(chatMessage.getType()==0){
            out.writeInt(chatMessage.getContentSize());
            out.writeBytes(chatMessage.getContent().getBytes());
        }else {
            out.writeInt(chatMessage.getNameSize());
            out.writeCharSequence(chatMessage.getNameTail(),StandardCharsets.UTF_8);
            out.writeInt(chatMessage.getContentSize());
            out.writeCharSequence(chatMessage.getContent(),StandardCharsets.UTF_8);
            out.writeLong(chatMessage.getDataSize());
            FileChannel fileChannel = new FileInputStream(chatMessage.getContent()).getChannel();
            System.out.println(System.currentTimeMillis());
            long c = 0;
            long size = chatMessage.getDataSize();
            while (size>100){
//   写入数据会自动 扩容    从256  256*2   256*2*2   .......
                System.out.println(out.writerIndex()+"     "+ out.capacity());
                size = size-100;
                int i = out.writeBytes(fileChannel, c, 100);
                System.out.println(out.isWritable());
                c=c+100;
            }
            out.writeBytes(fileChannel,c, (int) size);
            fileChannel.close();
            System.out.println("文件发送完毕");
        }


    }

    @Override
    protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf in, List<Object> out) throws Exception {
        System.out.println("开始解码");
        ChatMessage chatMessage = new ChatMessage();
        chatMessage.setMagic(in.readInt()).setVersion(in.readByte())
                .setType(in.readByte()).setCharset(in.readByte());
        if(chatMessage.getType() == 0){
            chatMessage.setContentSize(in.readInt());
            CharSequence charSequence = in.readCharSequence(chatMessage.getContentSize(), StandardCharsets.UTF_8);
            chatMessage.setContent(charSequence.toString());
            out.add(chatMessage);
        }else {
            chatMessage.setNameSize(in.readInt());
            chatMessage.setNameTail(in.readCharSequence(chatMessage.getNameSize(),StandardCharsets.UTF_8).toString());
            chatMessage.setContentSize(in.readInt());
            CharSequence charSequence = in.readCharSequence(chatMessage.getContentSize(), StandardCharsets.UTF_8);
            chatMessage.setContent(charSequence.toString());
            chatMessage.setDataSize(in.readLong());
            out.add(chatMessage);
            String path ="C:\\Users\\艾桑\\Desktop\\数据生成器\\netty\\netty-50000\\src\\main\\resources\\static\\download\\";
            File file1 = new File(path);
            if(file1.isDirectory()){
                file1.mkdirs();
            }
            File file = new File(path + UUID.randomUUID() + chatMessage.getNameTail());
            try {
                file.createNewFile();
            }catch (Exception e){
                e.printStackTrace();
            }
            long size = chatMessage.getDataSize();
            FileChannel fileChannel = new FileOutputStream(file).getChannel();
//  输出到文件只能输出剩下的字节数, 输出后不能扩容  ByteBuf为不可读状态  reader和writer都为2048
//  那么请问如何读取剩下的数据呢?  急
            while (size>0){
                try {
                    if(!in.isReadable()){
                        in.markWriterIndex();
                    }
                    int i = in.readBytes(fileChannel,in.readableBytes());
                    size =size -i;
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
            fileChannel.close();
            System.out.println(System.currentTimeMillis());
            System.out.println("文件接收完毕");

        }

    }

Answer 1

发送大文件都是要循环分块处理的，定义字节数组为2048大小，循环处理即可。