I have a file that I've been reading into a List via the following method:
List<String> doc = java.nio.file.Files.readAllLines(new File("/path/to/src/resources/citylist.csv").toPath(), StandardCharsets.UTF_8);
Is there any nice (single-line) Java 7/8/nio2 way to pull off the same feat with a file that's inside an executable Jar (and presumably, has to be read with an InputStream)? Perhaps a way to open an InputStream via the classloader, then somehow coerce/transform/wrap it into a Path object? Or some new subclass of InputStream or Reader that contains an equivalent to File.readAllLines(...)?
I know I could do it the traditional way in a half page of code, or via some external library... but before I do, I want to make sure that recent releases of Java can't already do it "out of the box".
To read all lines from a file, we can use the Files. readAllLines() method. It takes the path to the file and the charset to use for decoding from bytes to characters. It returns the lines from the file as a list and throws an IOException if an I/O error occurs reading from the stream.
Reader is Character Based, it can be used to read or write characters. FileInputStream is Byte Based, it can be used to read bytes. FileReader is Character Based, it can be used to read characters. FileInputStream is used for reading binary files.
An InputStream
represents a stream of bytes. Those bytes don't necessarily form (text) content that can be read line by line.
If you know that the InputStream
can be interpreted as text, you can wrap it in a InputStreamReader
and use BufferedReader#lines()
to consume it line by line.
try (InputStream resource = Example.class.getResourceAsStream("resource")) { List<String> doc = new BufferedReader(new InputStreamReader(resource, StandardCharsets.UTF_8)).lines().collect(Collectors.toList()); }
You can use Apache Commons IOUtils#readLines:
List<String> doc = IOUtils.readLines(inputStream, StandardCharsets.UTF_8);
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With