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)
Related
I know I'm not doing something correctly. I know the file needs to be Serializable to read a text file.
I've got implements Serializable on the main class. But my readText and my writeText aren't converting.
Nothing is coming in when I read and when I write out the file is not text.
public static ArrayList<String> readText() {
ArrayList<String> read = new ArrayList<String>();
Frame f = new Frame();
FileDialog foBox = new FileDialog(f, "Reading serialized file",
FileDialog.LOAD);
foBox.setVisible(true);
String foName = foBox.getFile();
String dirPath = foBox.getDirectory();
File inFile = new File(dirPath + foName);
BufferedReader in = null;
ObjectInputStream OIS = null;
try {
in = new BufferedReader(new FileReader(inFile));
} catch (FileNotFoundException e1) {
e1.printStackTrace();
}
String line = null;
try {
line = in.readLine();
} catch (IOException e1) {
e1.printStackTrace();
while (line != null) {
try {
FileInputStream IS = new FileInputStream(inFile);
OIS = new ObjectInputStream(IS);
inFile = (File) OIS.readObject();
} catch (IOException io) {
io.printStackTrace();
System.out.println("An IO Exception occurred");
}
catch (ClassNotFoundException cnf) {
cnf.printStackTrace(); // great for debugging!
System.out.println("An IO Exception occurred");
} finally
{
try {
OIS.close();
} catch (Exception e) {
}
}
}
}
return read;
}
public static void writeText(ArrayList<String> file) {
ArrayList<String> write = new ArrayList<String>();
Frame f = new Frame();
FileDialog foBox = new FileDialog(f, "Saving customer file",
FileDialog.SAVE);
foBox.setVisible(true);
String foName = foBox.getFile();
String dirPath = foBox.getDirectory();
File outFile = new File(dirPath + foName);
PrintWriter out = null;
try {
out = new PrintWriter(new BufferedWriter(new FileWriter(outFile)));
for (int i = 0; i < write.size(); i++) {
String w = write.get(i);
out.println(file.toString());
}
}
catch (IOException io) {
System.out.println("An IO Exception occurred");
io.printStackTrace();
} finally {
try {
out.close();
} catch (Exception e) {
}
}
}
Nothing is coming in
You're never calling read.add(line) and you're attempting to read the file within an infinite loop inside of the catch block, which is only entered if you are not able to read the file.
Just use one try block, meaning try to open and read the file at once, otherwise, there's no reason to continue trying to read the file if it's not able to be opened
List<String> read = new ArrayList<>();
try (BufferedReader br = new BufferedReader(new FileReader(inFile)) {
String line = null;
while ((line = in.readLine()) != null) {
read.add(line); // need this
}
} catch (Exception e) {
e.printStackTrace();
}
return read;
Now, whatever you're doing with this serialized object stuff, that's completely separate, and it isn't the file or your main class that needs set to Serializable, it's whatever object you would have used a writeObject method on. However, you're reading and writing String objects, which are already Serializable.
when I write out the file is not text
Not sure what you mean by not text, but if you followed the above code, you'll get exactly what was in the initial file... Anyway, you do not need a write list variable.
You must use the individual lines of ArrayList<String> file parameter instead, but not file.toString()
for (String line:file) {
out.println(line);
}
out.close(); // always close your files and writers
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 some code that takes a file called wonder1.txt and writes the date in that file to another file. Lets say I have more files like wonder2.txt, wonder3.txt, wonder4.txt. How do I write the rest in the same file.
import java.io.*;
import java.util.*;
import java.lang.*;
public class alice {
public static void main(String[] args) throws FileNotFoundException, IOException {
String fileName = ("/Users/DAndre/Desktop/Alice/wonder1.txt");
BufferedReader br = new BufferedReader(new FileReader(fileName));
try {
StringBuilder stringBuilder = new StringBuilder();
String line = br.readLine();
while (line != null) {
stringBuilder.append(line);
stringBuilder.append("\n");
line = br.readLine();
}
/**
* Pass original file content as string to another method which
* creates new file with same content.
*/
newFile(stringBuilder.toString());
} finally {
br.close();
}
}
public static void newFile(String fileContent) {
try {
String newFileLocation = "/Users/DAndre/Desktop/Alice/new1.txt";
PrintWriter writer = new PrintWriter(newFileLocation);
writer.write(fileContent);//Writes original file content into new file
writer.close();
System.out.println("File Created");
} catch (Exception e) {
e.printStackTrace();
}
}
}
If you have list of files, then you can loop over them one by one. Your current code moves inside the loop.
The easier way would be to put all the files in one folder and read from it.
Something like this :
File folder = new File("/Users/DAndre/Desktop/Alice");
for (final File fileEntry : folder.listFiles()) {
String fileName = fileEntry.getAbsolutePath();
BufferedReader br = new BufferedReader(new FileReader(fileName));
try {
StringBuilder stringBuilder = new StringBuilder();
String line = br.readLine();
while (line != null) {
stringBuilder.append(line);
stringBuilder.append("\n");
line = br.readLine();
}
/**
* Pass original file content as string to another method which
* creates new file with same content.
*/
newFile(stringBuilder.toString());
} finally {
br.close();
}
}
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 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