I am using Netbeans on OS X and cannot seem to write text to a text file that I have in a package named "assets".
Below is the way I tried to accomplish writing to the text file and so far my method of doing this is not working.
The way I tried to approach this problem was converting a string to url, then converting the url to a uri. Then I used the uri for the new file parameter. After I tried to write a string using the class print writer.
public class Experiment {
File createFile(String path) {
java.net.URL url = getClass().getResource(path);
URI uri;
try {
uri = url.toURI();
}
catch (URISyntaxException e) {
uri = null;
}
if ((url != null) && (uri != null)) {
System.out.println("file loading sucess");
return new File(uri);
}
else {
System.out.println("Error file has not been loaded");
return null;
}
}
File file = createFile("/assets/myfile.txt");
public static void main(String[] args) {
Experiment testrun = new Experiment();
try {
PrintWriter writer = new PrintWriter(new FileWriter(testrun.file));
writer.println("it works");
writer.flush();
writer.close();
System.out.println("string was written");
}
catch (IOException e) {
System.out.println("there was an error while writing");
}
}
}
The output given from my try catch statements say that the file write code was executed.
file loading sucess
string was written
BUILD SUCCESSFUL (total time: 2 seconds)
I have also tried using absolute string paths for making a new file, but with null results. I am running out of ideas and hoping for some guidance or solution from somebody.
Related
I'm trying to copy files from the assets folder to the device folder using this function:
public static void copyJSON(Context aContext) {
AssetManager assetManager = aContext.getResources().getAssets();
String[] pFiles = null;
try {
pFiles = assetManager.list("ConfigurationFiles");
} catch (IOException e) {
Log.e("tag", "Failed to get asset file list.", e);
}
if (pFiles != null) for (String pJsonFileName : pFiles) {
InputStream tIn = null;
OutputStream tOut = null;
try {
tIn = assetManager.open("ConfigurationFiles" + File.separator + pJsonFileName);
String[] pList = aContext.getFilesDir().list(); //just for test
File pOutFile = new File(aContext.getFilesDir(), pJsonFileName);
tOut = new FileOutputStream(pOutFile);
if (pOutFile.exists()) {
copyFile(tIn, tOut);
}
} catch (IOException e) {
Log.e("tag", "Failed to copy asset file: " + pJsonFileName, e);
} finally {
if (tIn != null) {
try {
tIn.close();
} catch (IOException e) {
Log.e("tag", "Fail closing", e);
}
}
if (tOut != null) {
try {
tOut.close();
} catch (IOException e) {
Log.e("tag", "Fail closing", e);
}
}
}
}
}
If I delete the App and run the code, the variable pList is empty as I expect but the pOutFile.exists()returns true ALWAYS!!.
I don't want to copy them again every time I open my App, and I'm doing this because all my app uses JSON to navigate thru all the screens, so If I change any value in my BBDD a WS send a new JSON file and the App respond in accordance for example a button is no longer needed, so the first time you download my App I copy the original JSON and then if you use the app an if you have internet connection you will download a new JSON file that it is more accurate than the one that is in the Bundle and it will be override, this is because as far as I know I can't change the files that are in the assets folder.
I have read everywhere and all say the same use this:
File pOutFile = new File(aContext.getFilesDir(), pJsonFileName);
And then ask for this:
pOutFile.exists()
I don't know what I'm doing wrong.
Thanks for all your help.
put it this way:
File pOutFile = new File(aContext.getFilesDir(), pJsonFileName);
if (pOutFile.exists()) {
tOut = new FileOutputStream(pOutFile);
copyFile(tIn, tOut);
}
and everything should work fine. Remember the FileOutputStream creates the file it should stream to if possible and non existing
The problem is you're essentially creating a file and then checking if it exists.
try {
tIn = assetManager.open("ConfigurationFiles" + File.separator + pJsonFileName);
String[] pList = aContext.getFilesDir().list(); //just for test
File pOutFile = new File(aContext.getFilesDir(), pJsonFileName);
// See here: you're creating a file right here
tOut = new FileOutputStream(pOutFile);
// And that file will be created in the exact location of the file
// you're trying to check:
if (pOutFile.exists()) { // Will always be true if FileOutputStream was successful
copyFile(tIn, tOut);
}
}
You should instead create your FileOutputStream AFTER you've done your existence check.
Source: http://docs.oracle.com/javase/7/docs/api/java/io/FileOutputStream.html
A file that you have just created without getting an exception always exists. The test is pointless. Remove it.
My data is not getting transferred to the output file , I always get an Exception.
import java.io.*;
import java.util.*;
class TransferData {
public static void main(String[] args) {
String path1="E:\\IO\\Input.txt";
String path2="E:\\IO\\Output.txt";
int data;
System.out.println("Transfering started...");
try {
FileInputStream fis=new FileInputStream(path1);
FileOutputStream fos=new FileOutputStream(path2);
while((data=fis.read())!=-1) {
fos.write(data);
}
}
catch(Exception e) {
System.out.println("exception caught!");
}
System.out.println("Completed...");
}
}
How do I transfer data to output file ?
Tested this code on my local machine it is works without exceptions.
Check is file E:/IO/Input.txt exists.
IS Directory E:/IO is writeable for your user
(If file E:/IO/Output.txt already exists check is it writeable and not opened in another programm)
By code:
It is good practice to close FIS and FOS after programm finished execution.
public class TransferData {
public static void main(String[] args) {
String path1 = "E:\\IO\\Input.txt";
String path2 = "E:\\IO\\Output.txt";
int data;
System.out.println("Transfering started...");
FileInputStream fis = null;
FileOutputStream fos = null;
try {
fis = new FileInputStream(path1);
fos = new FileOutputStream(path2);
while ((data = fis.read()) != -1) {
fos.write(data);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (fis != null) {
fis.close();
}
if (fos != null) {
fos.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
System.out.println("Completed...");
}
}
If you replace System.out.println("exception caught!"); with e.printStackTrace(); then you will get a much more useful error message.
If you then post that error message here, people will be able to help you much more easily.
It could be the case that the program cannot find the file you're trying to read.
I highly suggest to use e.printStackTrace() as the others suggested.
One possible problem might be the filesystem permissions or the file you are trying to read from being not existent.
You might also want to use a "try with resources" to simplify your code.
Your code is missing a close statement for your Streams too.
All together your code would look something like this:
import java.io.*;
import java.util.*;
class TransferData {
public static void main(String[] args) {
String path1="E:\\IO\\Input.txt";
String path2="E:\\IO\\Output.txt";
int data;
System.out.println("Transfering started...");
try (
FileInputStream fis=new FileInputStream(path1);
FileOutputStream fos=new FileOutputStream(path2)
) {
while((data=fis.read())!=-1) {
fos.write(data);
}
}
catch(Exception e) {
e.printStackTrace();
}
}
}
One last thing, if you post your code on StackOverflow, please do not mix different formatting styles (e.g. { in the same line as an if and sometimes in the next) and try to have the code well formatted from the beginning.
Add e.printStackTrace() to your catch block, and post the data printed in your console here, people will be able to help you better.
The most likely cause of the exception getting thrown is that the system is not able to find the file "E:\\IO\\Input.txt" or "E:\\IO\\Output.txt" make sure that the file's are there and Output.txt is not set to read only.
I have put a file "template.html" inside RAW folder and I want to read it into a InputStream. But it is returning me null. Can't understand what is wrong in the below code
e.g. fileName passed as parameter is "res/raw/testtemplate.html"
public String getFile(String fileName) {
InputStream input = this.getClass().getClassLoader().getResourceAsStream(fileName);
return getStringFromInputStream(input);
}
Also, there might be a better solution by putting these files in a particular subfolder and putting it inside Asset folder but then I believe I would need to pass context in AssetManager. I don't understand that solution, sorry I am new to android development. Can someone shed some light regarding how this approach can be achieved.
EDIT
I have started implementing this solution with Assets. Below method is supposed to return a string containing the entire text of the file stored as template.html.
getFile("template.html") // I am sending extension this time
Problem getting error getAssets() is undefined.
public String getFile(String fileName) {
BufferedReader reader = null;
StringBuilder sb = new StringBuilder();
String line;
try {
reader = new BufferedReader(new InputStreamReader(getAssets().open(fileName)));
while ((line = reader.readLine()) != null) {
sb.append(line);
}
}
catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return sb.toString();
}
use this
new BufferedInputStream(getResources().openRawResource(filepath));
this will return a buffered input stream
The file name should be without extension :
InputStream ins = getResources().openRawResource(
getResources().getIdentifier("raw/FILENAME_WITHOUT_EXTENSION",
"raw", getPackageName()));
For this purposes uses assets folder:
assets/
This is empty. You can use it to store raw asset files. Files that you save here are compiled into an .apk file as-is, and the original filename is preserved. You can navigate this directory in the same way as a typical file system using URIs and read files as a stream of bytes using the AssetManager. For example, this is a good location for textures and game data.
So, you could easy get access at assets with context: context.getAssets()
BufferedReader reader = null;
try {
reader = new BufferedReader(
new InputStreamReader(context.getAssets().open("filename.txt")));
}
} catch (IOException e) {
//log the exception
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
//log the exception
}
}
}
Goal: Print the data from a .dat file to the console using Eclipse.
(Long-Term Goal): Executable that I can pass a .dat file to and it creates a new txt file with the data formatted.
The .dat: I know the .dat file contains control points that I will need to create a graph with using ECMAScript.
Eclipse Setup:
Created Java Project
New > Class .. called the Class FileRead
Now I have FileRead.java which is:
1/ package frp;
2/
3/ import java.io.BufferedReader;
4/ import java.io.File;
5/ import java.io.FileReader;
6/
7/ public class FileRead {
8/
9/ public static void main(String[] args) {
10/ FileReader file = new FileReader(new File("dichromatic.dat"));
11/ BufferedReader br = new BufferedReader(file);
12/ String temp = br.readLine();
13/ while (temp != null) {
14/ temp = br.readLine();
15/ System.out.println(temp);
16/ }
17/ file.close();
18/ }
19/
20/ }
Please note this approach was borrowed from here: https://stackoverflow.com/a/18979213/3306651
1st Challenge: FileNotFoundException on LINE 10
Screenshot of Project Explorer:
QUESTION: How to correctly reference the .dat file?
2nd Challenge: Unhandled exception type IOException LINES 12, 14, 17
QUESTION: How to prevent these exceptions?
Thank you for your time and effort to help me, I am recreating Java applets using only JavaScript. So, I'm looking to create java tools that extract data I need to increase productivity. If you are interested in phone/web app projects involving JavaScript, feel free to contact me 8503962891
1. Without changing your code, you must place the file in the project's root folder.
Otherwise, reference it as src/frp/dichromatic.dat
2. Doing something like this:
public static void main(String[] args) {
FileReader file = null;
try {
file = new FileReader(new File("dichromatic.dat"));
} catch (FileNotFoundException e1) {
System.err.println("File dichromatic.dat not found!");
e1.printStackTrace();
}
BufferedReader br = new BufferedReader(file);
String line;
try {
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
System.err.println("Error when reading");
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
System.err.println("Unexpected error");
e.printStackTrace();
}
}
}
}
3. Creation of a new txt file "formatted". In this example, the formatting will be settings the characters to uppercase.
public static void main(String[] args) {
FileReader file = null;
BufferedWriter bw = null;
File outputFile = new File("output.formatted");
try {
file = new FileReader(new File("dichromatic.dat"));
} catch (FileNotFoundException e1) {
System.err.println("File dichromatic.dat not found!");
e1.printStackTrace();
}
try {
bw = new BufferedWriter(new FileWriter(outputFile));
} catch (IOException e1) {
System.err.println("File is not writtable or is not a file");
e1.printStackTrace();
}
BufferedReader br = new BufferedReader(file);
String line;
String lineformatted;
try {
while ((line = br.readLine()) != null) {
lineformatted = format(line);
bw.write(lineformatted);
// if you need it
bw.newLine();
}
} catch (IOException e) {
System.err.println("Error when processing the file!");
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
System.err.println("Unexpected error");
e.printStackTrace();
}
}
if (bw != null) {
try {
bw.close();
} catch (IOException e) {
System.err.println("Unexpected error");
e.printStackTrace();
}
}
}
}
public static String format(String line) {
// replace this with your needs
return line.toUpperCase();
}
I would strongly recommend spending some time reading through the Java Trails Tutorials. To answer your specific question, look at Lesson: Exceptions.
To oversimplify, just wrap the file-handling code in a try...catch block. By example:
package frp;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
public class FileRead {
public static void main(String[] args) {
try {
FileReader file = new FileReader(new File("dichromatic.dat"));
BufferedReader br = new BufferedReader(file);
String temp = br.readLine();
while (temp != null) {
temp = br.readLine();
System.out.println(temp);
}
file.close();
} catch (FileNotFoundException fnfe) {
System.err.println("File not found: " + fnfe.getMessage() );
} catch (IOException ioe) {
System.err.println("General IO Error encountered while processing file: " + ioe.getMessage() );
}
}
}
Note that ideally, your try...catch should wrap the smallest possible unit of code. So, wrap the FileReader separately, and "fail-fast" if the file isn't found, and wrap the readLine loop in its own try...catch. For more examples and a better explanation of how to deal with exceptions, please reference the link I provided at the top of this answer.
Edit: issue of file path
Not finding the file has to do with the location of the file relative to the root of the project. In your original post, you reference the file as "dichromatic.dat" but relative to the project root, it is in "src/frp/dichromatic.dat". As rpax recommends, either change the string that points to the file to properly reference the location of the file relative to the project root, or move the file to project root and leave the string as-is.
I'm using the following code to upload an xml file to the directory /home/domainname/public_html/guest in the server. However, the file is uploaded only to the location /home/domainname. It is not uploading to the child directories. Please advise.
FTPClient client = new FTPClient();
FileInputStream fis = null;
try {
client.connect(Util.getProductsXMLFTPServer());
client.login(Util.getProductsXMLFTPUser(), Util.getProductsXMLFTPPassword());
//
// Create an InputStream of the file to be uploaded
//
fis = new FileInputStream(new File(Util.getProductsXMLFTPInputFilePath(), Util.getProductsXMLFTPOutputFileName()));
client.changeWorkingDirectory(Util.getProductsXMLFTPUploadPath());
client.storeFile(Util.getProductsXMLFTPOutputFileName(), fis);
client.logout();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (fis != null) {
fis.close();
}
client.disconnect();
} catch (IOException e) {
e.printStackTrace();
}
}
I checked your code, it works. I've only changed file type declaration to binary, which may be not needed for XML files.
Here's my complete code for reference:
package apachenet.ftp;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
public class App {
public static void main( String[] args ) {
FTPClient client = new FTPClient();
FileInputStream fis = null;
try {
client.connect(/*Util.getProductsXMLFTPServer()*/"127.0.0.1");
client.login(/*Util.getProductsXMLFTPUser()*/"pwyrwinski",
/*Util.getProductsXMLFTPPassword()*/"secret");
client.setFileType(FTP.BINARY_FILE_TYPE); // optional
fis = new FileInputStream(
new File(/* Util.getProductsXMLFTPInputFilePath() */"/home/pwyrwinski",
/* Util.getProductsXMLFTPOutputFileName() */"img.png"));
client.changeWorkingDirectory(/*Util.getProductsXMLFTPUploadPath()*/ "someDir");
client.storeFile(/*Util.getProductsXMLFTPOutputFileName()*/"img_bis.png", fis);
client.logout();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (fis != null) {
fis.close();
}
client.disconnect();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
As you can see it's roughly the same as yours.
Util class calls are replaced with raw data.
When I ran it, file /home/pwyrwinski/img.png was uploaded to {FTP_USER_ROOT}/someDir directory on ftp server with name changed to img_bis.png. I assume this is exactly what you wanted to achieve.
Let's go back to your problem.
Try to check what is returned from
Util.getProductsXMLFTPUploadPath() call. My guess is it's not what
you're expecting - so debug it in your IDE or print it to the console.
Check if path returned from Util.getProductsXMLFTPUploadPath()
call starts with slash, it shouldn't.
UPDATE 1.
Does direcory /home/domainname/public_html/guest exist on server?
Add following method to your class:
private static void showServerReply(FTPClient ftpClient) {
String[] replies = ftpClient.getReplyStrings();
if (replies != null && replies.length > 0) {
for (String aReply : replies) {
System.out.println("SERVER: " + aReply);
}
}
}
and call it after every ftp-client's method call. This will give you codes and descriptions of every command result. I suspect client.changeWorkingDirectory(...) ends with error, probably: 550 Permission Denied (or No such file or folder).
Next modification will be:
client.login(Util.getProductsXMLFTPUser(), Util.getProductsXMLFTPPassword());
System.out.println(client.printWorkingDirectory()); // added this line!
this will tell us what is current working directory after login in.
Please post your results.
FTPClient ftpClient = new FTPClient();
try {
System.out.println("before server connection");
ftpClient.connect(server, port);
System.out.println("before user name and passwod");
ftpClient.login(user, pass);
ftpClient.enterLocalActiveMode();
ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
System.out.println("connection sucess");
// windows working fine
File secondLocalFile = new File("/home/aims/archived_reports/tes_S_000000123/test.pdf");
// String secondRemoteFile = "/archived_reports/PermanentRecord.pdf";
//linux
// File secondLocalFile = new File("/archived_reports/tes_S_000009123/test.pdf");
String secondRemoteFile = "remotefilename.pdf";
InputStream inputStream = new FileInputStream(secondLocalFile);
System.out.println("Start uploading second file");
ftpClient.changeWorkingDirectory("/reports");// home/ftp.test/reports folder
System.out.println("Prasent Working Directory :"+ftpClient.printWorkingDirectory());
OutputStream outputStream = ftpClient.storeFileStream(secondRemoteFile);
int returnCode = ftpClient.getReplyCode();
System.out.println(returnCode);
byte[] bytesIn = new byte[4096];
int read = 1;
while ((read = inputStream.read(bytesIn)) != -1) {
outputStream.write(bytesIn, 0, read);
}
System.out.println();
inputStream.close();
outputStream.close();
boolean completed = ftpClient.completePendingCommand();
if (completed) {
System.out.println("The second file is uploaded successfully.");
}