Netty-promise

public class TimeEncoder extends ChannelOutboundHandlerAdapter {
 
    @Override
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
        UnixTime m = (UnixTime)msg;
        ByteBuf encoded = ctx.alloc().buffer(4);
        encoded.writeInt((int)m.value());
        ctx.write(encoded,promise);//(1)
        promise.setSuccess();
    }
 
}

报：Failed to mark a promise as success because it has succeeded already

解决：

法1：write方法中的promise去掉。因为，write中带参数 promise，会自动执行promise.setSuccess();

法2：去掉promise.setSuccess();

promise目的是通知ChannelFutureListener执行。