I have a resource file in my /res/raw/ folder (/res/raw/textfile.txt) which I am trying to read from my android app for processing.
public static void main(String[] args) {
File file = new File("res/raw/textfile.txt");
FileInputStream fis = null;
BufferedInputStream bis = null;
DataInputStream dis = null;
try {
fis = new FileInputStream(file);
bis = new BufferedInputStream(fis);
dis = new DataInputStream(bis);
while (dis.available() != 0) {
// Do something with file
Log.d("GAME", dis.readLine());
}
fis.close();
bis.close();
dis.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
I have tried different path syntax but always get a java.io.FileNotFoundException error. How can I access /res/raw/textfile.txt for processing? Is File file = new File("res/raw/textfile.txt"); the wrong method in Android?
***** Answer: *****
// Call the LoadText method and pass it the resourceId
LoadText(R.raw.textfile);
public void LoadText(int resourceId) {
// The InputStream opens the resourceId and sends it to the buffer
InputStream is = this.getResources().openRawResource(resourceId);
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String readLine = null;
try {
// While the BufferedReader readLine is not null
while ((readLine = br.readLine()) != null) {
Log.d("TEXT", readLine);
}
// Close the InputStream and BufferedReader
is.close();
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
Note this will return nothing, but will print the contents line by line as a DEBUG string in the log.
If you have a file in res/raw/textfile.txt from your Activity/Widget call:
getResources().openRawResource(...) returns an InputStream
The dots should actually be an integer found in R.raw... corresponding to your filename, possibly R.raw.textfile (it's usually the name of the file without extension)
new BufferedInputStream(getResources().openRawResource(...)); then read the content of the file as a stream
Related
Below I have the following code to read in a file and go through it line by line.. This is using java's BufferedReader class. That I am fine with.
String filename = "C:\\test.txt"
String line = null;
FileReader fileReader = new FileReader(filename);
BufferedReader bufferedReader = new BufferedReader(fileReader);
try {
while (((line = bufferedReader.readLine()) != null)) {
//do the following....
}
} catch (IOException) {
e.printStackTrace();
}
However I want to now start using InputStreamReader in Spring / Java. I have the below code written but I am unsure how I can step through my file line by line. Really confused over this part. Anyone have any ideas or know how this can be done?
String filepath= "C:\\test.txt"
File filename= new File(filepath);
try {
InputStream fileInputStream = new BOMInputStream(new fileInputStream(filename));
// now want to step through the file, line by line..
} catch (IOException) {
e.printStackTrace();
}
Thanks
This is how you can read your input file byte by byte using InputStreamReader.
char[] chars = new char[100];
try {
InputStream inputStream = new FileInputStream("C:\\test.txt");
InputStreamReader inputStreamReader = new InputStreamReader(inputStream,"UTF-8");
inputStreamReader.read(chars);
System.out.println(new String(chars).trim());
} catch (IOException e) {
e.printStackTrace();
}
Check this out -
String filename = "C:\\test.txt"
String line = null;
FileInputStream fileInputStream = new FileInputStream(filename);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));
try {
while (((line = bufferedReader.readLine()) != null)) {
//do the following....
}
} catch (IOException) {
e.printStackTrace();
}
public static void main(String[] args) {
try (BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("c:\\test.txt")))) {
reader.lines().forEach(line -> {
// do what you want with the line
});
} catch (IOException e) {
throw new RuntimeException(e);
}
}
I'm trying to webget some bz2 files from Wikipedia, I don't care whether they are save as bz2 or unpacked, since I can unzip them locally.
When I call:
public static void getZip(String theUrl, String filename) throws IOException {
URL gotoUrl = new URL(theUrl);
try (InputStreamReader isr = new InputStreamReader(new BZip2CompressorInputStream(gotoUrl.openStream())); BufferedReader in = new BufferedReader(isr)) {
StringBuffer sb = new StringBuffer();
String inputLine;
// grab the contents at the URL
while ((inputLine = in.readLine()) != null) {
sb.append(inputLine + "\r\n");
}
// write it locally
Wget.createAFile(filename, sb.toString());
} catch (MalformedURLException mue) {
mue.printStackTrace();
} catch (IOException ioe) {
throw ioe;
}
}
I get a part of the unzipped file, never more than +- 883K.
When I don't use the BZip2CompressorInputStream, like:
public static void get(String theUrl, String filename) throws IOException {
try {
URL gotoUrl = new URL(theUrl);
InputStreamReader isr = new InputStreamReader(gotoUrl.openStream());
BufferedReader in = new BufferedReader(isr);
StringBuffer sb = new StringBuffer();
String inputLine;
// grab the contents at the URL
while ((inputLine = in.readLine()) != null) {
sb.append(inputLine);// + "\r\n");
}
// write it locally
Statics.writeOut(filename, false, sb.toString());
} catch (MalformedURLException mue) {
mue.printStackTrace();
} catch (IOException ioe) {
throw ioe;
}
}
I get a file of which the size is the same as it suppose to (compared to the KB not B). But also a message that that the zipped file is damaged, also when using byte [] instead of readLine(), like:
public static void getBytes(String theUrl, String filename) throws IOException {
try {
char [] cc = new char[1024];
URL gotoUrl = new URL(theUrl);
InputStreamReader isr = new InputStreamReader(gotoUrl.openStream());
BufferedReader in = new BufferedReader(isr);
StringBuffer sb = new StringBuffer();
// grab the contents at the URL
int n = 0;
while (-1 != (n = in.read(cc))) {
sb.append(cc);// + "\r\n");
}
// write it locally
Statics.writeOut(filename, false, sb.toString());
} catch (MalformedURLException mue) {
mue.printStackTrace();
} catch (IOException ioe) {
throw ioe;
}
}
Finally, when I bzip2 the inputstream and outputstream, I get a valid bzip2 file, but of the size like the first one, using:
public static void getWriteForBZ2File(String urlIn, final String filename) throws CompressorException, IOException {
URL gotoUrl = new URL(urlIn);
try (final FileOutputStream out = new FileOutputStream(filename);
final BZip2CompressorOutputStream dataOutputStream = new BZip2CompressorOutputStream(out);
final BufferedInputStream bis = new BufferedInputStream(gotoUrl.openStream());
final CompressorInputStream input = new CompressorStreamFactory().createCompressorInputStream(bis);
final BufferedReader br2 = new BufferedReader(new InputStreamReader(input))) {
String line = null;
while ((line = br2.readLine()) != null) {
dataOutputStream.write(line.getBytes());
}
}
}
So, how do I get the entire bz2 file, in either bz2 format or unzipped?
A bz2 file contains bytes, not characters. You can't read it as if it contained characters, with a Reader.
Since all you want to do is download the file and save it locally, all you need is
Files.copy(gotoUrl.openStream(), Paths.get(fileName));
I am trying to read values from CSV file which is present in package com.example.
But when i run code with the following syntax:
DataModel model = new FileDataModel(new File("Dataset.csv"));
It says:
java.io.FileNotFoundException:Dataset.csv
I have also tried using:
DataModel model = new FileDataModel(new File("/com/example/Dataset.csv"));
Still not working.
Any help would be helpful.
Thanks.
If this is the FileDataModel from org.apache.mahout.cf.taste.impl.model.file then it can't take an input stream and needs just a file. The problem is you can't assume the file is available to you that easily (see answer to this question).
It might be better to read the contents of the file and save it to a temp file, then pass that temp file to FileDataModel.
InputStream initStream = getClass().getClasLoader().getResourceAsStream("Dataset.csv");
//simplistic approach is to put all the contents of the file stream into memory at once
// but it would be smarter to buffer and do it in chunks
byte[] buffer = new byte[initStream.available()];
initStream.read(buffer);
//now save the file contents in memory to a temporary file on the disk
//choose your own temporary location - this one is typical for linux
String tempFilePath = "/tmp/Dataset.csv";
File tempFile = new File(tempFilePath);
OutputStream outStream = new FileOutputStream(tempFile);
outStream.write(buffer);
DataModel model = new FileDataModel(new File(tempFilePath));
...
public class ReadCVS {
public static void main(String[] args) {
ReadCVS obj = new ReadCVS();
obj.run();
}
public void run() {
String csvFile = "file path of csv";
BufferedReader br = null;
String line = "";
String cvsSplitBy = ",";
try {
br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
// Do stuff here
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
System.out.println("Done");
}
}
CSV file which is present in package com.example
You can use getResource() or getResourceAsStream() to access the resource from within the package. For example
InputStream is = getClass().getResourceAsStream("/com/example/Dataset.csv");//uses absolute (package root) path
BufferedReader br = new BufferedReader(new InputStreamReader(is));
//read from BufferedReader
(note exception handling and file closing are omitted above for brevity)
I am trying to read a text file and save each line of text into an ArrayList. I have tried various methods, including FileInputStream and BufferedReader. Here is the code that currently gets me the closest to what I am trying to do
try {
InputStream is = getResources().openRawResource(R.File.txt);
BufferedReader bufferedReader = new BufferedReader(new FileReader("File.txt"));
String line;
while((line = bufferedReader.readLine()) != null)
{
allText.add(line);
}
bufferedReader.close();
}
catch(IOException e)
{
}
allText is an ArrayList previously instantiated. Right now the file is saved in /res and I get an "invalid resource directory warning". I would like to know where to save the file properly and how to read from it.
The line should be
InputStream is = getResources().openRawResource(R.File.txt);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(is));
You have made an InputStream for resource file and use BufferedReader to read from the stream created.
Reading from /assets folder use getAssets() method
BufferedReader reader = null;
try {
reader = new BufferedReader(
new InputStreamReader(getAssets().open("File.txt"), "UTF-8"));
String myData = reader.readLine();
while (myData != null) {
myData = reader.readLine();
}
} catch (IOException e) {
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
}
}
}
Reading file from /res/raw folder
InputStream fileInputStream = getResources().openRawResource(R.raw.File);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
byte buf[] = new byte[1024];
int len;
try {
while ((len = fileInputStream .read(buf)) != -1) {
outputStream.write(buf, 0, len);
}
outputStream.close();
fileInputStream .close();
} catch (IOException e) {
}
return outputStream.toString();
}
I'd like to send a file contained in a ZIP archive unzipped to an external program for further decoding and to read the result back into Java.
ZipInputStream zis = new ZipInputStream(new FileInputStream(ZIPPATH));
Process decoder = new ProcessBuilder(DECODER).start();
???
BufferedReader br = new BufferedReader(new InputStreamReader(
decoder.getInputStream(),"us-ascii"));
for (String line = br.readLine(); line!=null; line = br.readLine()) {
...
}
What do I need to put into ??? to pipe the zis content to the decoder.getOutputStream()? I guess a dedicated thread is needed, as the decoder process might block when its output is not consumed.
Yes a thread is needed (or you wait/block until the copy is finished) for copying the InputStream to the OutputStream. Check the org.apache.commons.net.io.Util class for several helper methods to copy the data.
Ok, I got as far as following:
public class CopyStream extends Thread {
static final int BUFFERSIZE = 10 * 1024;
InputStream input; OutputStream output;
boolean closeInputOnExit, closeOutputOnExit, flushOutputOnWrite;
public IOException ex;
public CopyStream (InputStream input, boolean closeInputOnExit, OutputStream output, boolean closeOutputOnExit,
boolean flushOutputOnWrite) {
super("CopyStream");
this.input = input; this.closeInputOnExit = closeInputOnExit;
this.output = output; this.closeOutputOnExit = closeOutputOnExit;
this.flushOutputOnWrite = flushOutputOnWrite;
start();
}
public void run () {
try {
byte[] buffer = new byte[BUFFERSIZE];
for (int bytes = input.read(buffer); bytes>=0; bytes = input.read(buffer)) {
output.write(buffer,0,bytes);
if (flushOutputOnWrite) output.flush();
}
} catch (IOException ex) {
this.ex = ex;
} finally {
if (closeInputOnExit) {
try {
input.close();
} catch (IOException ex) {
if (this.ex==null) this.ex = ex;
}
}
if (closeOutputOnExit) {
try {
output.close();
} catch (IOException ex) {
if (this.ex==null) this.ex = ex;
}
}
}
}
}
Then the code would look as following:
ZipInputStream zis = new ZipInputStream(new FileInputStream(ZIPPATH));
for (ZipEntry ze = zis.getNextEntry(); ze!=null; ze = zis.getNextEntry()) {
Process decoder = new ProcessBuilder(EXTERNALPROCESSOR).start();
CopyStream cs1 = new CopyStream(is,false,decoder.getOutputStream(),true,true);
CopyStream cs2 = new CopyStream(decoder.getErrorStream(),true,System.err,false,true);
BufferedReader br = new BufferedReader(new InputStreamReader(decoder.getInputStream(),"us-ascii"));
ArrayList<String> lines = new ArrayList<String>();
for (String line = br.readLine(); line!=null; line = br.readLine()) {
lines.add(line);
}
if (decoder.exitValue()!=0) throw new IOException("Decoder exits with "+decoder.exitValue());
try {
cs1.join(100);
} catch (InterruptedException ex) {
throw new IOException(ex);
}
if (cs1.isAlive()) throw new IOException("cs1 not terminated");
if (cs1.ex!=null) throw cs1.ex;
try {
cs2.join(100);
} catch (InterruptedException ex) {
throw new IOException(ex);
}
if (cs2.isAlive()) throw new IOException("cs2 not terminated");
if (cs2.ex!=null) throw cs2.ex;
for (String line: lines) {
processline(line);
}
}
However, I find this a bit fragile. Isn't this a pattern for which some more robust implementation is around?