netty 中ByteBuf 的api

主要用于存取数据

package netty;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;

import java.nio.charset.Charset;

public class Buf02
{
    public static void main(String[] args) {
        ByteBuf buf = Unpooled.copiedBuffer("hello北京", Charset.forName("utf-8"));//接收的类型是String是 CharSequence的实现类  因为要准备数据的传输，所以要编码。


        if(buf.hasArray()){
            byte[] array = buf.array();
            System.out.println(new String(array, Charset.forName("utf-8")));
            System.out.println("buf = " + buf);
            System.out.println("buf.arrayOffset() = " + buf.arrayOffset());
            System.out.println("buf.readerIndex() = " + buf.readerIndex());
            System.out.println("buf.writerIndex() = " + buf.writerIndex());
            System.out.println("buf.capacity() = " + buf.capacity());
            buf.readByte();//这个操作，会导致下边的减少
            System.out.println("buf.readableBytes() = " + buf.readableBytes());
            for (int i = 0; i < buf.readableBytes(); i++) {
                System.out.println("buf.getByte(i) = " + (char)buf.getByte(i));//这个方法是自己去，不会改变索引
                //默认输出的是整形，所强转下

            }
            System.out.println("buf.getCharSequence(0,6,Charset.forName(\"utf-8\")) = " + buf.getCharSequence(0, 6, Charset.forName("utf-8")));

        }
    }
}