InputStream转成Byte数组

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本文介绍三种将InputStream转成Byte数组的方法：

只使用JDK

固定大小的stream

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InputStream initialStream = new ByteArrayInputStream(new byte[] {0, 1, 2});
byte[] targetArray = new byte[initialStream.available()];
initialStream.read(targetArray);

不固定大小的stream

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InputStream is = new ByteArrayInputStream(new byte[] {0, 1, 2});
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
int nRead;
byte[] data = new byte[1024];
while ((nRead = is.read(data, 0, data.length)) != -1) {
    buffer.write(data, 0, nRead);
}
buffer.flush();
byte[] byteArray = buffer.toByteArray();

使用Guava

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InputStream initialStream = ByteSource.wrap(new byte[] {0, 1, 2}).openStream();
byte[] targetArray = ByteStreams.toByteArray(initialStream);

使用Commons IO

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ByteArrayInputStream initialStream = new ByteArrayInputStream(new byte[] {0, 1, 2});
byte[] targetArray = IOUtils.toByteArray(initialStream);

http://www.baeldung.com/convert-input-stream-to-array-of-bytes