java - 从一个字节到另一个字节读取流

Question

这是我的心理挑战，当我在 HttpRequest 或任何输入流中设置字节范围时，选择下载的时间间隔是多少？!闭区间[开始，结束]还是左闭右开[开始，结束]？!

Answer 1

看看HTTP specification, chapter 14: Header Field Definitions :

14.35 Range

14.35.1 Byte Ranges

The first-byte-pos value in a byte-range-spec gives the byte-offset of the first byte in a range. The last-byte-pos value gives the byte-offset of the last byte in the range; that is, the byte positions specified are inclusive. Byte offsets start at zero.

那里的例子非常具有描述性:

Examples of byte-ranges-specifier values (assuming an entity-body of length 10000):

• The first 500 bytes (byte offsets 0-499, inclusive): bytes=0-499
• The second 500 bytes (byte offsets 500-999, inclusive): bytes=500-999
• The final 500 bytes (byte offsets 9500-9999, inclusive): bytes=-500
• Or bytes=9500-

简而言之:间隔是封闭的(包含)，要下载的字节数是last - first + 1。