ByteBuf buf = Unpooled.buffer(10); buf.writerIndex(5);
ByteBuf buf = Unpooled.buffer(10); buf.writeByte(1); buf.writeByte(2); buf.writeByte(3); buf.writerIndex(buf.writerIndex() + 1);This code creates a ByteBuf buffer with a capacity of 10 bytes, then writes three bytes (1, 2, 3) to the buffer. After that, it increments the writerIndex by 1. This means that the last byte (3) has been overwritten and the current write position is at the end of the buffer. In conclusion, the java io.netty.buffer ByteBuf class provides a flexible way to manage data in network applications. The writerIndex() method makes it easy to control the write position of the buffer, and its usability shows that it is a popular package library.