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);
}
}
Related
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 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();
}
At the moment i'm trying to save a response to the internal storage in the phone. Everything works fine up until i try and retrieve the data again. When i log out the retrieved data it only logs out one small section of the response and the rest isn't there. Ive tried deleting the file and calling it again just incase it was using an old one.
Saving Code
try {
String response = apiResponse.getRawResponse();
Log.e("Response", response);
FileOutputStream userInfo = openFileOutput("personal_profile", MODE_PRIVATE);
userInfo.write(response.getBytes());
userInfo.close();
} catch (Exception e) {
e.printStackTrace();
Retrieving Code
String response = "";
try {
FileInputStream fis = getActivity().openFileInput("personal_profile");
DataInputStream isr = new DataInputStream(fis);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(isr));
StringBuilder sb = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
sb.append(line);
}
line = response;
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Log.e("Saved File", response);
Any kind of suggestions would be great!
REASON
The problem was that the line variable is assigned again in every iteration
Try this:
String response = "";
try {
FileInputStream fis = getActivity().openFileInput("personal_profile");
DataInputStream isr = new DataInputStream(fis);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(isr));
StringBuilder sb = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
sb.append(line);
}
line = response;
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
CHANGE LAST LINE
Log.e("Saved File", sb.toString());
Have you got this in your AndroidManifest.xml file?
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
Also, this link has everything you need to know about reading and writing files:
http://www.anddev.org/working_with_files-t115.html
Code::
String response = "";
try {
FileInputStream fis = getActivity().openFileInput("personal_profile");
DataInputStream isr = new DataInputStream(fis);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(isr));
StringBuilder sb = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
sb.append(line);
}
line = response;
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Log.e("Saved File", sb.toString());
Ok, forgive my beginner-ness and please tell me how I can output my text from "before.txt" into a fresh new file called "after". Obviously I have altered the text along the way to make it lower-case and eliminate non alphabetic characters.
import java.io.*;
public class TextReader {
public void openFile() throws IOException {
try {
// Read in the file
BufferedReader br = new BufferedReader(
new FileReader(
new File("before.txt")));
String currentLine = br.readLine();
currentLine = currentLine.toLowerCase();
currentLine = currentLine.replaceAll("[A-Z]", "");
br.close(); // Close br to prevent resource leak
}
// Exception if the file is not in the path specified
catch (Exception e) {
System.out.println("Error: File not found");
}
}
public void writeFile() throws IOException {
BufferedWriter output = new BufferedWriter(new FileWriter("/WS3Ex3/after.txt"));
output.write("before.txt");
output.close();
}
}
What about this
public void openFile() throws IOException {
try {
// Read in the file
BufferedReader br = new BufferedReader(
new FileReader(
new File("before.txt")));
String currentLine = br.readLine();
currentLine = currentLine.toLowerCase();
currentLine = currentLine.replaceAll("[A-Z]", "");
br.close(); // Close br to prevent resource leak
writeFile(currentLine);
}
// Exception if the file is not in the path specified
catch (Exception e) {
System.out.println("Error: File not found");
}
}
public void writeFile(String text) throws IOException {
BufferedWriter output = new BufferedWriter(new FileWriter("/WS3Ex3/after.txt"));
output.write(text);
output.close();
}
}
Let me guess, is this a school assignment?
Try this:
public void ReadAndWrite() throws IOException {
try {
// Read in the file
BufferedWriter output = new BufferedWriter(new FileWriter("/WS3Ex3/after.txt"));
BufferedReader br = new BufferedReader(
new FileReader(
new File("before.txt")));
String currentLine;
while((currentLine = br.readLine()) != NULL){
currentLine = currentLine.toLowerCase();
currentLine = currentLine.replaceAll("[A-Z]", "");
output.write(currentLine);
}
br.close(); // Close br to prevent resource leak
output.close();
}
// Exception if the file is not in the path specified
catch (Exception e) {
System.out.println("Error: File not found");
}
}
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