mark()
开始缓冲位置,以便
reset()
数据样本:A B C D
System.out.println((char)buffer.read());
System.out.println((char)buffer.read());
buffer.mark(4); // save the position
System.out.println((char)buffer.read());
System.out.println((char)buffer.read());
buffer.reset() // back to 4
System.out.println((char)buffer.read());
System.out.println((char)buffer.read());
A、B、C、D
(作为一个字符需要2个字节)