在commons-io包中org.apache.commons.io.IOUtils類的toByteArray(InputStream input)已經有實現了,我們可以參考下思路,完成我們的方法,我們可以用類似下面的程式碼實現inputStream轉化為byte[]陣列

public static byte[] toByteArray(InputStream input) throws IOException {
    ByteArrayOutputStream output = new ByteArrayOutputStream();
    byte[] buffer = new byte[4096];
    int n = 0;
    while (-1 != (n = input.read(buffer))) {
        output.write(buffer, 0, n);
    }
    return output.toByteArray();
}
 

下面是IOUtils中摘錄出與toByteArray相關的方法

org.apache.commons.io.IOUtils.toByteArray

方法如下:
public static byte[] toByteArray(InputStream input)
  throws IOException
{
  ByteArrayOutputStream output = new ByteArrayOutputStream();
  copy(input, output);
  return output.toByteArray();
}

public static int copy(InputStream input, OutputStream output)
  throws IOException
{
  long count = copyLarge(input, output);
  if (count > 2147483647L) {
    return -1;
  }
  return (int)count;
}

public static long copyLarge(InputStream input, OutputStream output)
  throws IOException
{
  byte[] buffer = new byte[4096];
  long count = 0L;
  int n = 0;
  while (-1 != (n = input.read(buffer))) {
    output.write(buffer, 0, n);
    count += n;
  }
  return count;
}