java中的io流问题 FileInputStream中的read()返回的int类型是读取字节的

Question

java中的io流问题FileInputStream中的read()返回的int类型是读取字节的ASCLL编码么？是一个一个字节读？BufferedInputStream中的read()返回的是读入字节的长度吗？是一段一段的读吗？谢谢了，感觉好疑惑

Answer 1

不是，两个都是返回Ascll编码，bufferInputStream是缓冲流，提高效率

Answer 2

FileInputStream是基础类，字节流，按字节读取。
BufferedInputStream是包装类，处理流，先将数据读于缓冲区，然后再读取

Answer 3

看源码啊，FileInputStream

/**
* Reads a byte of data from this input stream. This method blocks
* if no input is yet available.
*
* @return the next byte of data, or <code>-1</code> if the end of the
* file is reached.
* @exception IOException if an I/O error occurs.
*/
public native int read() throws IOException;

BufferedInputStream

/**
* See
* the general contract of the <code>read</code>
* method of <code>InputStream</code>.
*
* @return the next byte of data, or <code>-1</code> if the end of the
* stream is reached.
* @exception IOException if this input stream has been closed by
* invoking its {@link #close()} method,
* or an I/O error occurs.
* @see java.io.FilterInputStream#in
*/
public synchronized int read() throws IOException {
if (pos >= count) {
fill();
if (pos >= count)
return -1;
}
return getBufIfOpen()[pos++] & 0xff;
}