It’s not foolproof but it’s probably the easiest and doesn’t rely on any external data. Like all decent formats, GZip too begins with a magic number which can be quickly checked without reading the entire stream. public static InputStream decompressStream(InputStream input) { PushbackInputStream pb = new PushbackInputStream( input, 2 ); //we need a pushbackstream to … Read more
Because a byte can only hold -128 until 127, while it should return 0 until 255 (and -1 when there’s no byte left (i.e. EOF)). Even if it returned byte, there would be no room to represent EOF. A more interesting question is why it doesn’t return short.
Use FileInputStream: InputStream is = new FileInputStream(“/res/example.xls”); But never read from raw file input stream as this is terribly slow. Wrap it with buffering decorator first: new BufferedInputStream(is); BTW leading slash means that the path is absolute, not relative.
In InputStreams, read() calls are said to be “blocking” method calls. That means that if no data is available at the time of the method call, the method will wait for data to be made available. The available() method tells you how many bytes can be read until the read() call will block the execution … Read more
It’s right there in JDK! Quoting JavaDoc of SequenceInputStream: A SequenceInputStream represents the logical concatenation of other input streams. It starts out with an ordered collection of input streams and reads from the first one until end of file is reached, whereupon it reads from the second one, and so on, until end of file … Read more
Is there any faster way of doing this in Java? Yes. Scanner is fairly slow (at least according to my experience). If you don’t need to validate the input, I suggest you just wrap the stream in a BufferedInputStream and use something like String.split / Integer.parseInt. A small comparison: Reading 17 megabytes (4233600 numbers) using … Read more
Use ByteArrayInputStream: InputStream is = new ByteArrayInputStream(decodedBytes);
In FileInputStream, the method read() reads a single byte. From the source code: /** * 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 … Read more
The Properties class wraps the input stream in a LineReader to read the properties file. Since you provide the input stream, it’s your responsibility to close it. The second example is a better way to handle the stream by far, don’t rely on somebody else to close it for you. One improvement you could make … Read more
Just because you use a buffer doesn’t mean the stream has to fill that buffer. In other words, this should be okay: public static void copyStream(InputStream input, OutputStream output) throws IOException { byte[] buffer = new byte[1024]; // Adjust if you want int bytesRead; while ((bytesRead = input.read(buffer)) != -1) { output.write(buffer, 0, bytesRead); } … Read more