ImageIO 读取 ByteArrayInputStream 为空

Question

我有这段代码

System.out.println  ("fileData 1 -> " + fileData);

ByteArrayInputStream in = new ByteArrayInputStream(fileData);

System.out.println  ("fileData 2 -> " + in);

try {
    BufferedImage img = ImageIO.read(in);
    System.out.println  ("fileData 3 -> " + img);

....

这是我在控制台中看到的：

fileData 1 -> [B@7a677c
fileData 2 -> java.io.ByteArrayInputStream@203aa8
fileData 3 -> null

为什么 BufferedImage 为空且不抛出异常？

Answer 1

documentation表示可以为空：

Returns a BufferedImage as the result of decoding a supplied InputStream with an ImageReader chosen automatically from among those currently registered. The InputStream is wrapped in an ImageInputStream. If no registered ImageReader claims to be able to read the resulting stream, null is returned. [...]

ImageIO 读取 ByteArrayInputStream 为空

ImageIO is null reading ByteArrayInputStream

java

image

java-io