i want to append a text in an existing file but i can not read it(i can read the first inserted data) i do not know what is the mistake .
this is the write code(save in file):
FileOutputStream fos = openFileOutput("test",MODE_APPEND);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(text);
oos.flush();
oos.close();
and this is how to read(read the data from the file):
FileInputStream fis = openFileInput("test");
ObjectInputStream ois = new ObjectInputStream(fis);
String s=(String) ois.readObject();
while(s != null){
Toast.makeText(getApplicationContext(),s, Toast.LENGTH_SHORT).show();
s=(String) ois.readObject();
Toast.makeText(getApplicationContext(),s, Toast.LENGTH_SHORT).show();
}
pleas help me !! are there a wrong in writing or in the reading code
public boolean writeToFile(String filename,String data){
try {
FileOutputStream fos = openFileOutput(filename,0);
OutputStreamWriter out = new OutputStreamWriter(openFileOutput(filename,0));
out.write(data);
out.close();
return true;
} catch (java.io.IOException e) {
e.printStackTrace();
System.out.println("-----problem in writeToFile()--------");
return false;
}
}
public String readFromFile(String xxx){
StringBuffer returnString = new StringBuffer(""); ;
try{
FileInputStream fstream = openFileInput(xxx);
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
while ((strLine = br.readLine()) != null) {
returnString.append(strLine);
}
in.close();
}catch (Exception e){//Catch exception if any
e.printStackTrace();
System.out.println("-----problem in readFromFile()--------");
}
return returnString.toString();
}
Related
I have a problem of writing the UTF-8 character that cannot be properly read by Excel. When I open the excel, some characters are read as "Ņӊഎ«". I understand this is something to do the UTF BOM. Is there someone who how can help to explain me this?
Here are my codes for writing the CSV.
public class FileWriter {
private static String filenameTemp;
public static boolean creatFile(String name) throws IOException {
boolean flag = false;
filenameTemp = name + "";
System.out.println("write to file: "+filenameTemp);
File filename = new File(filenameTemp);
if (!filename.exists()) {
filename.createNewFile();
flag = true;
}
else {
filename.delete();
filename.createNewFile();
flag = true;
}
return flag;
}
public static boolean writeFile(String newStr) throws IOException {
boolean flag = false;
String filein = newStr + "\r\n";
String temp = "";
FileInputStream fis = null;
InputStreamReader isr = null;
BufferedReader br = null;
FileOutputStream fos = null;
PrintWriter pw = null;
try {
File file = new File(filenameTemp);
fis = new FileInputStream(file);
isr = new InputStreamReader(fis);
br = new BufferedReader(isr);
StringBuffer buf = new StringBuffer();
for (int j = 1; (temp = br.readLine()) != null; j++) {
buf = buf.append(temp);
buf = buf.append(System.getProperty("line.separator"));
}
buf.append(filein);
fos = new FileOutputStream(file);
byte[] unicode = {(byte)0xEF, (byte)0xBB, (byte)0xBF};
fos.write(unicode);
pw = new PrintWriter(fos);
pw.write(buf.toString().toCharArray());
pw.flush();
flag = true;
} catch (IOException e1) {
throw e1;
} finally {
if (pw != null) {
pw.close();
}
if (fos != null) {
fos.close();
}
if (br != null) {
br.close();
}
if (isr != null) {
isr.close();
}
if (fis != null) {
fis.close();
}
}
return flag;
}
I have searched in stack and web a lot, for parsing a CSV file.
But I won't get what I want.
I have this table in CSV format,
what I want is, if I give the "ID"(which is 0,1,2,3... ) it should return me the value right to it i.e., if i give
"2" it should return me "hello how are you ?".
"4" it should return me "What do you prefer over tea ?"
How to achieve this?
Right now I kept my CSV file in the raw folder.
Any help will be apppreciated
You can save data in CSV as:-
ArrayList<TableData> arrayList=new ArrayList<>();
arrayList.add(new TableData(1,"Hello"));
arrayList.add(new TableData(2,"How are u"));
arrayList.add(new TableData(3,"I am fine"));
arrayList.add(new TableData(4,"Thank You"));
File file;
File root = Environment.getExternalStorageDirectory();
if (root.canWrite()){
File dir = new File (root.getAbsolutePath() + "/PersonData");
dir.mkdirs();
file = new File(dir, "Data.csv");
FileOutputStream out = null;
try {
// write to byte array
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(baos);
for (TableData element : arrayList) {
dos.writeUTF(String.valueOf(element.id));
dos.writeUTF(String.valueOf(element.name));
}
byte[] bytes = baos.toByteArray();
out = new FileOutputStream(file);
out.write(bytes);
out.close();
}catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
And Retrive it as:-
File file;
File root = Environment.getExternalStorageDirectory();
File dir = new File (root.getAbsolutePath() + "/PersonData");
dir.mkdirs();
file = new File(dir, "Data.csv");
Uri u1 = null;
u1 = Uri.fromFile(file);
try {
FileInputStream inputStream=new FileInputStream(file);
String input="2";
String previousValue="";
ByteArrayInputStream bais = new ByteArrayInputStream(readFully(inputStream));
DataInputStream in = new DataInputStream(bais);
while (in.available() > 0) {
String element = in.readUTF();
if(previousValue.equalsIgnoreCase(input)){
textView.setText(element);
}
previousValue=element;
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Method to convert inputStream to byte[]:-
public static byte[] readFully(InputStream input) throws IOException
{
byte[] buffer = new byte[8192];
int bytesRead;
ByteArrayOutputStream output = new ByteArrayOutputStream();
while ((bytesRead = input.read(buffer)) != -1)
{
output.write(buffer, 0, bytesRead);
}
return output.toByteArray();
}
Create a separate class for reading CSV file as:-
public class CSVFile {
InputStream inputStream;
public CSVFile(InputStream inputStream){
this.inputStream = inputStream;
}
public List read(){
List resultList = new ArrayList();
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
try {
String csvLine;
while ((csvLine = reader.readLine()) != null) {
String[] row = csvLine.split(",");
resultList.add(row);
}
}
catch (IOException ex) {
throw new RuntimeException("Error in reading CSV file: "+ex);
}
finally {
try {
inputStream.close();
}
catch (IOException e) {
throw new RuntimeException("Error while closing input stream: "+e);
}
}
return resultList;
}
}
Now call this in your activity:-
String input="2";
InputStream inputStream = getResources().openRawResource(R.raw.sample);
CSVFile csvFile = new CSVFile(inputStream);
List scoreList = csvFile.read();
for(int i=0;i<scoreList.size();i++){
Object data_list=scoreList.get(i);
String a[]= (String[]) data_list;
String id=a[0];
String value=a[1];
if(input.equalsIgnoreCase(id)){
Log.d("TAG", "Value Found "+value);
}
}
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 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