ByteBuffer 类型化put和get

放入什么类型，取出就要用什么类型，顺序要一致。否则会报 BufferUnderflowException

测试代码

public static void main(String[] args) {
    ByteBuffer buffer = ByteBuffer.allocate(1024);
    buffer.putInt(100);
    buffer.putLong(100L);
    buffer.putChar('陈');
    buffer.putShort((short) 4);

    //调用buffer.flip() 切换到读模式
    buffer.flip();

    System.out.println(buffer.getInt());
    System.out.println(buffer.getLong());
    System.out.println(buffer.getChar());
    System.out.println(buffer.getShort());
}