Write InputStream to a file

Question

I have an object, in this object I have an InputStream which contains a file.

I want to write what is inside of InputStream to a file inside of a folder.

How would I go about doing this in Core Java?

I was able to print out each line of the InputStream using BufferedReader and .readLine(), however I want the entire file wrote to disk not just what is inside of it.

Hopefully this makes sense, thank you.

Answer 1

If you are using Java 7 or above you can use java.nio.file.Files:

InputStream in = obj.getInputStrem();
Path file = ...;
Files.copy(in, path);

It also supports different options (see CopyOption implementations like StandardCopyOption and LinkOption)

Answer 2

Pretty sure its out there already, you could google it. But as you asked about writing to a file inside of a folder, assuming the InputStream variable is named "input":

FileOutputStream output = null;
try {
    // Create folder (if it doesn't already exist)
    File folder = new File("<path_to_folder>\\<folder_name>");
    if (!folder.exists()) {
        folder.mkdirs();
    }
    // Create output file
    output = new FileOutputStream(new File(folder, "<file_name>"));
    // Write data from input stream to output file.
    int bytesRead = 0;
    byte[] buffer = new byte[4096];
    while ((bytesRead = input.read(buffer)) != -1) {
        output.write(buffer, 0, bytesRead);
    }
} catch (IOException ioex) {
    ioex.printStackTrace();
} finally {
    try {
        if (output != null) {
            output.close();
        }
    } catch (IOException ioex) {
        ioex.printStackTrace();
    }
    // Also close InputStream if no longer needed.
    try {
        if (input != null) {
            input.close();
        }
    } catch (IOException ioex) {
        ioex.printStackTrace();
    }
}