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read FIile content as bytes java

I have 2 java classes. Let them be class A and class B.
Class A gets String input from user and stores the input as byte into the FILE, then Class B should read the file and display the Byte as String.
CLASS A:
File file = new File("C:\\FILE.txt");
file.createNewFile();
FileOutputStream fos = new FileOutputStream(file);
String fwrite = user_input_1+"\n"+user_input_2;
fos.write(fwrite.getBytes());
fos.flush();
fos.close();
In CLASS B, I wrote the code to read the file, but I don't know how to read the file content as bytes.
CLASS B:
fr = new FileReader(file);
br = new BufferedReader(fr);
arr = new ArrayList<String>();
int i = 0;
while((getF = br.readLine()) != null){
arr.add(getF);
}
String[] sarr = (String[]) arr.toArray(new String[0]);
The FILE.txt has the following lines
[B#3ce76a1
[B#36245605
I want both these lines to be converted into their respective string values and then display it. How to do it?

Are you forced to save using a String byte[] representation to save data? Take a look at object serialization (Object Serialization Tutorial), you don't have to worry about any low level line by line read or write methods.

Since you are writing a byte array through the FileOutputStream, the opposite operation would be to read the file using the FileInputStream, and construct the String from the byte array:
File file = new File("C:\\FILE.txt");
Long fileLength = file.length();
byte[] bytes = new byte[fileLength.intValue()]
try (FileInputStream fis = new FileInputStream(file)) {
fis.read(bytes);
}
String result = new String(bytes);
However, there are better ways of writing the String to a file.
You could write it using the FileWriter, and read using FileReader (possibly wrapping them by the corresponding BufferedReader/Writer), this will avoid creating intermediate byte array. Or better yet, use Apache Commons' IOUtils or Google's Guava libraries.

Saving an FLV Stream

I currently am accessing a streaming h264 file and want to save it off for the ability to slice frames. However, I'm having issues saving/opening the .flv file
When pointing to the URL in the address bar - I am told it's an x-flv file.
I then attempt to do the following to save a chunk of the stream.
URL url = new URL("http://foo.bar.com/foo/bar");
HttpURLConnection conn = (HttpURLConnection) url
.openConnection(proxy);
conn.setRequestMethod("GET");
File f = new File("C:\\tmpArea\\tmp.flv");
FileWriter fr = new FileWriter(f);
bw = new BufferedWriter(fr);
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output = "";
int i = 0;
while (((output = br.readLine()) != null) && i < 100000) {
bw.write(output);
i++;
}
Upon doing this I've attempted to open the file in VLC Media Player and am told:
No suitable decoder module: VLC does not support the audio or video format "undf".
Unfortunately there is no way for you to fix this.
I then thought, well maybe it's not really an FLV file and that's on me. So I used a run of the mill hex-editor. Opening up the file in the HexEditor gives me the following information:
FLV
onMetaData
duration
width
height
videodatarate
framerate
videocodecid
audiodatarate
audiosamplerate
audiosamplesize
stereo
audiocodecid
encoder
Lavf52.10.6.0
filesize....
Is there a different way I should be trying to save off this data? Is there a conversion/codec issue I'm not seeing?

You are using a Reader and Writer, which are intended to read bytes and convert them to characters, to read a binary file that consists of bytes. The conversion from bytes to characters will corrupt the data. You should be using InputStream and OutputStream instead.

GAE: How do I read URL response line by line?

In Google App Engine, I tried reading a .txt file from a URL. Because the maximum allowed size is 1MB and the file is slightly larger, I'm using an alternative method described here.
So, what I'm trying to do is this:
FetchOptions fo = FetchOptions.Builder.allowTruncate().doNotFollowRedirects();
HTTPRequest request = new HTTPRequest(url,HTTPMethod.GET,FetchOptions.Builder.allowTruncate());
URLFetchService service = URLFetchServiceFactory.getURLFetchService();
HTTPResponse response = service.fetch(request);
My question is now, how can I read this response line by line? I'm trying to process each line which should be possible somehow as the source file is a simple text file.
I can get a byte[] with
byte[] content = response.getContent();
but I'm struggling with the further processing of it.
Or, can I do something completely different to achieve the same thing ?
I'm trying to read it line by line because I don't need all the lines. Processing would be much easier than to put everything in one large string.

You can try:
ByteArrayInputStream bais = new ByteArrayInputStream(content);
BufferedReader reader = new BufferedReader(new InputStreamReader(bais, "utf-8"));
String line = null;
while ((line = reader.readLine()) != null) {
...
}
Alternatively, you can use IOUtils and call IOUtils.lineIterator(reader) (where reader is the InputStreamReader)

How to read and write UTF-8 to disk on the Android?

I cannot read and write extended characters (French accented characters, for example) to a text file using the standard InputStreamReader methods shown in the Android API examples. When I read back the file using:
InputStreamReader tmp = new InputStreamReader(in);
BufferedReader reader = new BufferedReader(tmp);
String str;
while ((str = reader.readLine()) != null) {
...
the string read is truncated at the extended characters instead of at the end-of-line. The second half of the string then comes on the next line. I'm assuming that I need to persist my data as UTF-8 but I cannot find any examples of that, and I'm new to Java.
Can anyone provide me with an example or a link to relevant documentation?

Very simple and straightforward. :)
String filePath = "/sdcard/utf8_file.txt";
String UTF8 = "utf8";
int BUFFER_SIZE = 8192;
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(filePath), UTF8),BUFFER_SIZE);
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(filePath), UTF8),BUFFER_SIZE);

When you instantiate the InputStreamReader, use the constructor that takes a character set.
InputStreamReader tmp = new InputStreamReader(in, "UTF-8");
And do a similar thing with OutputStreamWriter
I like to have a
public static final Charset UTF8 = Charset.forName("UTF-8");
in some utility class in my code, so that I can call (see more in the Doc)
InputStreamReader tmp = new InputStreamReader(in, MyUtils.UTF8);
and not have to handle UnsupportedEncodingException every single time.

this should just work on Android, even without explicitly specifying UTF-8, because the default charset is UTF-8. if you can reproduce this problem, please raise a bug with a reproduceable test case here:
http://code.google.com/p/android/issues/entry

if you face any such kind of problem try doing this. You have to Encode and Decode your data into Base64. This worked for me. I can share the code if you need it.

Check the encoding of your file by right clicking it in the Project Explorer and selecting properties. If it's not the right encoding you'll need to re-enter your special characters after you change it, or at least that was my experience.

Reading Strings and Binary from the same FileInputStream

I have a file that contains some amount of plain text at the start followed by binary content at the end. The size of the binary content is determined by some one of the plain text lines I read.
I was using a BufferedReader to read the individual lines, however it exposes no methods to refer to read a byte array. The readUTF for a DataInputStream doesnt read all the way to the end of the line, and the readLine method is deprecated.
Using the underlying FileInputStream to read returns empty byte arrays. Any suggestions on how to go about this?
private DOTDataInfo parseFile(InputStream stream) throws IOException{
DOTDataInfo info = new DOTDataInfo();
BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
int binSize = 0;
String line;
while((line = reader.readLine()) != null){
if(line.length() == 0)
break;
DOTProperty prop = parseProperty(line);
info.getProperties().add(prop);
if(prop.getName().equals("ContentSize"))
binSize = Integer.parseInt(prop.getValue());
}
byte[] content = new byte[binSize];
stream.read(content); //Its all empty now. If I use a DataInputStream instead, its got the values from the file
return info;
}

You could use RandomAccessFile. Use readLine() to read the plain text at the start (note the limitations of this, as described in the API), and then readByte() or readFully() to read the subsequent binary data.
Using the underlying FileInputStream
to read returns empty byte arrays.
That's because you have wrapped the stream in a BufferedReader, which has probably consumed all the bytes from the stream when filling up its buffer.

If you genuinely have a file (rather than something harder to seek in, e.g. a network stream) then I suggest something like this:
Open the file as a FileInputStream
Wrap it in InputStreamReader and a BufferedReader
Read the text, so you can find out how much content there is
Close the BufferedReader (which will close the InputStreamReader which will close the FileInputStream)
Reopen the file
Skip to (total file length - binary content length)
Read the rest of the data as normal
You could just call mark() at the start of the FileInputStream and then reset() and skip() to get to the right place if you want to avoid reopening the file. (I was looking for an InputStream.seek() but I can't see one - I can't remember wanting it before in Java, but does it really not have one? Ick.)

You need to use an InputStream. Readers are for character data. Look into wrapping your input stream with a DataInputStream, like:
stream=new DataInputStream(new BufferedInputStream(new FileInputStream(...)));
The data input stream will give you many useful methods to read various types of data, and of course, the base InputStream methods for reading bytes.
(This is actually exactly what a HTTP server must do to read a request with content.)
The readUTF doesn't read a line, it reads a string that was written in (modified) UTF8 format - refer to the JavaDoc.

Alas, DataInputStream is deprecated and does not handle UTF. But this should help (it reads a line from a binary stream, without any lookahead).
public static String lineFrom(InputStream in) throws IOException {
byte[] buf = new byte[128];
int pos = 0;
for (;;) {
int ch = in.read();
if (ch == '\n' || ch < 0) break;
buf[pos++] = (byte) ch;
if (pos == buf.length) buf = Arrays.copyOf(buf, pos + 128);
}
return new String(Arrays.copyOf(buf, pos), "UTF-8");
}

The correct way is to use an InputStream of some form, probably a FileInputStream unless this becomes a performance barrier.
What do you mean "Using the underlying FileInputStream to read returns empty byte arrays."? This seems very unlikely and is probably where your mistake is. Can you show us the example code you've tried?

You can read the text with BufferedReader. When you know where the binary starts you can close the file and open it with RandomAccessFile and read binary from any point in the file.
Or you can read the file as binary and convert to text the sections you identify as text. {Using new String(bytes, encoding)}

I recommend using DataInputStream. You have the following options:
Read both text and binary content with DataInputStream
Open a BufferedReader, read text and close the stream. Then open a DataInputStream, skip bytes equal to the size of the text and read binary data.