Basically i have two questions. i am using the below code to read and write z text file.
File myFile = new File("/sdcard/mysdfile.txt");
myFile.createNewFile();
FileOutputStream fOut = new FileOutputStream(myFile);
OutputStreamWriter myOutWriter =
new OutputStreamWriter(fOut);
myOutWriter.append("my text here");
myOutWriter.close();
this create a new file every time i want this to OPEN_OR_CREATE(if file already exist don't create a new one)
Ad my second question is that how to change the path "/sdcard/mysdfile.txt" i want this file to stored in my sdcard -> subFolder1 -> SubFolder2
Thnaks
Do not use hardcoded /sdcard or /mnt/sdcard or your app will fail as devices vary on location or mountpoint of that storage. To get the right location use
Environment.getExternalStorageDirectory();
See docs here.
To append content to existing file use new FileOutputStream(myFile, true); instead of just new FileOutputStream(myFile); - see docs on that constructor here.
As for
how to change the path "/sdcard/mysdfile.txt"
Aside from getting rid of /sdcard as said above, just add subfolders to the paths: MyFolder1/MyFolder2/mysdfile.txt. Note these folder have to exists or the path will be invalid. You can always create it by calling myFile.mkdirs().
Replace
FileOutputStream fOut = new FileOutputStream(myFile);
with
FileOutputStream fOut = new FileOutputStream(myFile, true); //true means append mode.
Appart from that I have one suggestion for you.
Never never hardcode /sdcard in code,Rather consider writing.
File myFile = new File(Environment.getExternalStorageDirectory(),"mysdfile.txt");
Try my solution to write to end of text file
private void writeFile (String str){
try {
File f = new File(Environment.getExternalStorageDirectory().toString(),"tasklist.txt");
FileWriter fw = new FileWriter(f, true);
fw.write(str+"\n");
fw.flush();
fw.close();
} catch (Exception e) {
}
}
*File(Environment.getExternalStorageDirectory().toString()+"your/pth/here","tasklist.txt");
File dir = Environment.getExternalStorageDirectory();
File f = new File(dir+"/subFolder1/",xyz.txt); <-- HOW TO USE SUB FOLDER
if(file.exists())
{
// code to APPEND
}
else
{
// code to write new one
}
1> OPEN_OR_CREATE
You can try or can replace MODE_APPEND with true like #Vipul's suggestion
FileOutputStream fOut = openFileOutput(your_path_file, MODE_APPEND);
//it means if the file is exist the content you want write will append into it.
2> stored in my sdcard -> subFolder1 -> SubFolder2
you can use Environment.getExternalStorageDirectory().getAbsolutePath() to get full file path the SDCard. Then concat strings to get the file path you want. Ex:
String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath();
String fileName = "myFile.txt";
File f = new File(baseDir + File.separator + subfolder1 + File.separator + subfoler2, fileName);
In Java 7 we can do it this way:
Path path = Paths.get("/sdcard/mysdfile.txt");
BufferedWriter wrt = Files.newBufferedWriter(path, StandardCharsets.UTF_8, StandardOpenOption.APPEND);
Related
Team I'm trying to get all the paths from a directory and save all the directorys and files inside a txt file with the date.
Now I get all the directorys and files with file.getAbsolutePath(), but is only writing just a few paths.
File directory = new File(directoryName);
File[] fList = directory.listFiles();
String yourDesktopPath = System.getProperty("user.home") + "\\Desktop\\";
PrintWriter writer = new PrintWriter(yourDesktopPath+"the-file-name.txt", "UTF-8");
try {
for (File file : fList){
if (file.isFile()){
System.out.println(file.getAbsolutePath());
writer.write(file.getAbsolutePath());
} else if (file.isDirectory()){
listFilesAndFilesSubDirectories(file.getAbsolutePath());
}
}
writer.flush();
} finally {
writer.close();
}
You can simply use java.nio.file.Files and it will do the recursive looping for you, you can use it like this:
Files.walk(Paths.get("your_path"))
.map(path -> path.toAbsolutePath().toString())
.forEach(writer::write);
new PrintWriter(yourDesktopPath+"the-file-name.txt", "UTF-8"); truncates the file, erasing whatever you previously wrote to it.
You need to append to your file. FileOutputStream has a constructor which allows you to specify it:
PrintWriter writer = new PrintWriter(
new BufferedWriter(
new OutputStreamWriter(
new FileOutputStream(yourDesktopPath + "the-file-name.txt", true),
StandardCharsets.UTF_8));
I want to save a file in my desktop. So I have
FileOutputStream out = new FileOutputStream(new File("C:\\path_to_Dekstop\\print.xls"));
and it works. But I want to save the file without put the exact path to the desktop. I searched it and I found similar questions and I came up with this solution:
File desktopDir = new File(System.getProperty("user.home"), "Desktop");
System.out.println(desktopDir.getPath() + " " + desktopDir.exists());
String pathToDesktop = desktopDir.getPath();
FileOutputStream out = new FileOutputStream(new File(pathToDesktop));
but I got an error
java.io.FileNotFoundException: C:\Users\nat\Desktop (Access is denied)
pathToDesktop represents the directory of the Desktop, you should supply a file name to write to
FileOutputStream out = new FileOutputStream(new File(desktopDir, "File to be written to"));
Which will place the "File to be written to" on the desktop
You can't write directly to Desktop as its a folder but not a file. You need to write to a file. DO something like thi s:-
File desktopDir = new File(System.getProperty("user.home"), "Desktop");
System.out.println(desktopDir.getPath() + " " + desktopDir.exists());
String pathToDesktop = desktopDir.getPath();
FileOutputStream out = new FileOutputStream(new File(pathToDesktop+System.getProperty("file.separator")+"print.xls"));
This will write to print.xls in Desktop.
{
headFile = File.createTempFile("HMh", ".tmp");
headCreated = true;
dataFile = File.createTempFile("HMd",".tmp");
dataCreated = true;
headOut = new DataOutputStream((new BufferedOutputStream(new FileOutputStream(headFile))));
dataOut = new DataOutputStream((new BufferedOutputStream(new FileOutputStream(dataFile))));
}
I have this code where headOut is being referenced and writing temp File to headFile, I want to replace the temporary File with the File to be stored in Directory in Windows D Drive so as too see the Files being stored physically . Please help with the code . As it creates multiple Temp File please let know to append the File name with the Date Time value so as it doesent overide existing Temp Files .
long l = new Date().getTime();
File.createTempFile("HMh"+l, ".tmp") It will append timestamps to your file.
Write file on drive.
File file = new File("C:\\filename.txt");
// creates the file
file.createNewFile();
// creates a FileWriter Object
FileWriter writer = new FileWriter(file);
// Writes the content to the file
writer.write("This\n is\n an\n example\n");
This question already has an answer here:
Why FileWriter doesn't create a new file?
(1 answer)
Closed 8 years ago.
So I have a code snippet as follows. Im trying to find out why it throws a FileNotFoundException.
File file= new File (WORKSPACE_PATH+fname);
FileWriter fw;
if (file.exists())
{
fw = new FileWriter(file,true);//if file exists append to file. Works fine.
}
else
{
fw = new FileWriter(file);// If file does not exist. Create it. This throws a FileNotFoundException. Why?
}
Using concatenation when creating the File won't add the necessary path separator.
File file = new File(WORKSPACE_PATH, fname);
You need to add a separator (Windows : \ and Unix : /, you can use File.separator to get the system's separator) if WORKSPACE_PATH does not have one at its end, and manually creating the file with its parent directories might help.
Try this if WORKSPACE_PATH does not have a separator at its end :
File file = new File(WORKSPACE_PATH + File.separator + fname);
And add this before fw = new FileWriter(file);
file.mkdirs(); // If the directory containing the file and/or its parent(s) does not exist
file.createNewFile();
This might work:
File file= new File (WORKSPACE_PATH+fname);
FileWriter fw;
if (file.exists())
{
fw = new FileWriter(file,true);//if file exists append to file. Works fine.
}
else
{
file.createNewFile();
fw = new FileWriter(file);
}
I am creating a dat file in C: drive folder named abc as shown below , Now my file is generated everyday
now suppose if my file is generated today, then tommrow it will be also generated as usual
but when tommrow it is generated I have to make sure that earlier day file is deleted as the space in that folder is limited and this check is every time need to be done previos day file to be get deleted from that folder , please advise how to achieve this..
File file = new File(FilePath + getFileName()); //filepath is being passes through //ioc //and filename through a method
if (!file.exists()) {
file.createNewFile();
}
FileOutputStream fileOutput = new FileOutputStream(
file);
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
fileOutput));
why not use file.delete() ?
File file = new File(FilePath + getFileName()); //filepath is being passes through //ioc //and filename through a method
if (file.exists()) {
file.delete(); //you might want to check if delete was successfull
}
file.createNewFile();
FileOutputStream fileOutput = new FileOutputStream(file);
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fileOutput));
If your file name same in time to time no need to delete that. By running your code tomorrow, will over write file created today.
Consider following case
BufferedWriter bw=new BufferedWriter(new FileWriter("D:\\Test\test.txt"));
bw.write("abbbb");
bw.close(); // now this will create a test.txt in side Test folder
now run this by change writing String
BufferedWriter bw=new BufferedWriter(new FileWriter("D:\\test.txt"));
bw.write("hihi");
bw.close(); // now you can see file only containing hihi
You can change your code this way:
if (file.exists()) {
file.delete();
}
file.createNewFile();
And if it does not work, it's a matter of permission.
If you are using Java 7 then there is standard way to get file creation time, So that you can check if file is created in previous day and should be delete.
Path path = Paths.get("/filepath/");
BasicFileAttributes fileAttributes = Files.readAttributes(path, BasicFileAttributes.class);
System.out.println("creationTime:"+ fileAttributes.creationTime());