I have a web application, and I'm trying to return a boolean, of a .zip file that gets (successfully) generated on the server.
Locally I run this on Eclipse with Tomcat on Windows, but I am deploying it to a Tomcat Server on a Linux machine.
//.zip is generated successfully on the SERVER by this point
File file1 = new File("/Project/zip/theZipFile.zip");
boolean exists = file1.exists();// used to print if the file exists, returns false
if (exists)
fileLocation = "YES";
else
fileLocation = "No";
When I do this, it keeps returning false on the debugger and on my page when I print it out. I am sure it has something to do with file paths, but I am unsure.
Once I get the existence of the zip confirmed, I can easily use File.length() to get what I need.
Assume all getters and setters are in existence, and the JSF prints. It is mainly the Java backend I am having a slight issue with.
Thanks for any help! :)
Your path is not good. Try remove the leading / to fix the problem
See the test code for explanations :
import java.io.*;
public class TestFile {
public static void main(String[] args) {
try {
//Creates a myfile.txt file in the current directory
File f1 = new File("myfile.txt");
f1.createNewFile();
System.out.println(f1.exists());
//Creates a myfile.txt file in a sub-directory
File f2 = new File("subdir/myfile.txt");
f2.createNewFile();
System.out.println(f2.exists());
//Throws an IOException because of the leading /
File f3 = new File("/subdir/myfile.txt");
f3.createNewFile();
System.out.println(f3.exists());
} catch(IOException e) {
System.out.println(e.getMessage());
}
}
}
Debug using this statement
System.out.println("Actual file location : " + file1.getAbsolutePath());
This will tell you the absolute path of the file it's looking for
Related
I have below code where i am reading the file from particular directory, processing it and once processed i am moving the file to archive directory. This is working fine. I am receiving new file everyday and i am using Control-M scheduler job to run this process.
Now in next run i am reading the new file from that particularly directory again and checking this file with the file in the archive directory and if the content is different then only process the file else dont do anything. There is shell script written to do this job and we dont see any log for this process.
Now i want to produce log message in my java code if the files are identical from the particular directory and in the archive directory then generate log that 'files are identical'. But i dont know exactly how to do this. I dont want to write the the logic to process or move anything in the file ..i just need to check the files are equal and if it is then
produce log message. The file which i recieve are not very big and the max size can be till 10MB.
Below is my code:
for(Path inputFile : pathsToProcess) {
// read in the file:
readFile(inputFile.toAbsolutePath().toString());
// move the file away into the archive:
Path archiveDir = Paths.get(applicationContext.getEnvironment().getProperty(".archive.dir"));
Files.move(inputFile, archiveDir.resolve(inputFile.getFileName()),StandardCopyOption.REPLACE_EXISTING);
}
return true;
}
private void readFile(String inputFile) throws IOException, FileNotFoundException {
log.info("Import " + inputFile);
try (InputStream is = new FileInputStream(inputFile);
Reader underlyingReader = inputFile.endsWith("gz")
? new InputStreamReader(new GZIPInputStream(is), DEFAULT_CHARSET)
: new InputStreamReader(is, DEFAULT_CHARSET);
BufferedReader reader = new BufferedReader(underlyingReader)) {
if (isPxFile(inputFile)) {
Importer.processField(reader, tablenameFromFilename(inputFile));
} else {
Importer.processFile(reader, tablenameFromFilename(inputFile));
}
}
log.info("Import Complete");
}
}
Based on the limited information about the size of file or performance needs, something like this can be done. This may not be 100% optimized, but just an example. You may also have to do some exception handling in the main method, since the new method might throw an IOException:
import org.apache.commons.io.FileUtils; // Add this import statement at the top
// Moved this statement outside the for loop, as it seems there is no need to fetch the archive directory path multiple times.
Path archiveDir = Paths.get(applicationContext.getEnvironment().getProperty("betl..archive.dir"));
for(Path inputFile : pathsToProcess) {
// Added this code
if(checkIfFileMatches(inputFile, archiveDir); {
// Add the logger here.
}
//Added the else condition, so that if the files do not match, only then you read, process in DB and move the file over to the archive.
else {
// read in the file:
readFile(inputFile.toAbsolutePath().toString());
Files.move(inputFile, archiveDir.resolve(inputFile.getFileName()),StandardCopyOption.REPLACE_EXISTING);
}
}
//Added this method to check if the source file and the target file contents are same.
// This will need an import of the FileUtils class. You may change the approach to use any other utility file, or read the data byte by byte and compare. If the files are very large, probably better to use Buffered file reader.
private boolean checkIfFileMatches(Path sourceFilePath, Path targetDirectoryPath) throws IOException {
if (sourceFilePath != null) { // may not need this check
File sourceFile = sourceFilePath.toFile();
String fileName = sourceFile.getName();
File targetFile = new File(targetDirectoryPath + "/" + fileName);
if (targetFile.exists()) {
return FileUtils.contentEquals(sourceFile, targetFile);
}
}
return false;
}
I don't understand how to use TextIO's readFile(String Filename)
Can someone please explain how can I read an external file?
public static void readFile(String fileName) {
if (fileName == null) // Go back to reading standard input
readStandardInput();
else {
BufferedReader newin;
try {
newin = new BufferedReader( new FileReader(fileName) );
}
catch (Exception e) {
throw new IllegalArgumentException("Can't open file \"" + fileName + "\" for input.\n"
+ "(Error :" + e + ")");
}
if (! readingStandardInput) { // close current input stream
try {
in.close();
}
catch (Exception e) {
}
}
emptyBuffer(); // Added November 2007
in = newin;
readingStandardInput = false;
inputErrorCount = 0;
inputFileName = fileName;
}
}
I had to use TextIO for a school assignment and I got stuck on it too. The problem I had was that using the Scanner class I could just pass the name of the file as long as the file was in the same folder as my class.
Scanner fileScanner = new Scanner("data.txt");
That works fine. But with TextIO, this won't work;
TextIO.readfile("data.txt"); // can't find file
You have to include the path to the file like this;
TextIo.readfile("src/package/data.txt");
Not sure if there is a way to get it to work like the Scanner class or not, but this is what I've been doing in my course at school.
The above answer (about using the correct file name) is correct, however, as a clarification, make sure that you actually use the proper file path. The file path suggested above, i.e. src/package/ will not work in all circumstances. While this will be obvious to some, for those of you who need clarification, keep reading.
For example (and I use NetBeans), if you have already moved the file into NetBeans, and the file is already in the folder you want it to be in, then right click on the folder itself, and click 'properties'. Then expand the 'file path' section by clicking on the three dots next to the hidden file path. You will see the actual file path in its entirety.
For example, if the entire file path is:
C:\Users..\NetBeansProjects\IceCream\src\icecream\icecream.dat
Then, in the java code file itself, you can write:
TextIo.readfile("src/icecream/icecream.dat");
In other words, make sure you include the words 'src' but also everything that follows the src as well. If it's in the same folder as the rest of the files, you won't need anything prior to the 'src'.
I am trying to createNewFile() in java.I have written down the following example.I have compiled it but am getting a run time error.
import java.io.File;
import java.io.IOException;
public class CreateFileExample
{
public static void main(String [] args)
{
try
{
File file = new File("home/karthik/newfile.txt");
if(file.createNewFile())
{
System.out.println("created new fle");
}else
{
System.out.println("could not create a new file");
}
}catch(IOException e )
{
e.printStackTrace();
}
}
}
It is compiling OK.The run time error that I am getting is
java.io.IOException: No such file or directory
at java.io.UnixFileSystem.createFileExclusively(Native Method)
at java.io.File.createNewFile(File.java:947)
at CreateFileExample.main(CreateFileExample.java:16)
some points here
1- as Victor said you are missing the leading slash
2- if your file is created, then every time you invoke this method "File.createNewFile()" will return false
3- your class is very platform dependent (one of the main reasons why Java is powerful programming language is that it is a NON-PLATFORM dependent), instead you can detect a relative location throw using the System.getProperties() :
// get System properties :
java.util.Properties properties = System.getProperties();
// to print all the keys in the properties map <for testing>
properties.list(System.out);
// get Operating System home directory
String home = properties.get("user.home").toString();
// get Operating System separator
String separator = properties.get("file.separator").toString();
// your directory name
String directoryName = "karthik";
// your file name
String fileName = "newfile.txt";
// create your directory Object (wont harm if it is already there ...
// just an additional object on the heap that will cost you some bytes
File dir = new File(home+separator+directoryName);
// create a new directory, will do nothing if directory exists
dir.mkdir();
// create your file Object
File file = new File(dir,fileName);
// the rest of your code
try {
if (file.createNewFile()) {
System.out.println("created new fle");
} else {
System.out.println("could not create a new file");
}
} catch (IOException e) {
e.printStackTrace();
}
this way you will create your file in any home directory on any platform, this worked for my windows operating system, and is expected to work for your Linux or Ubuntu as well
You're missing the leading slash in the file path.
Try this:
File file = new File("/home/karthik/newfile.txt");
That should work!
Actually this error comes when there is no directory "karthik" as in above example and createNewFile() is only to create file not for directory use mkdir() for directory and then createNewFile() for file.
I am new for Importing file using scanner line by line reader .When i have import file it's working correctly , but some other system(i.e. colleague system) same project and same database connection while importing file error like Java.io.FileNotfoundException local drive fake path directory (e.g: "c:\fake path\db.sql").
public boolean checkfile(String dbfile){
File obj = new File(dbfile)
Scanner scr = new Scanner(obj );
try{
while(scr .hasNext()){
String scr_line = scr.nextLine();
System.out.println(scr_line );
}
}catch(Exception ex){
System.out.println(ex.tostring());
}
}
Above code File obj = new File(dbFile) this line error message showing like Java.io.FileNotFoundException local drive fake path directory . can any please help me where i have done mistake above this code .
1 , File you try read is not available in your colleague system or where you run this java program
2 , check this file "c:\fake path\db.sql" is available or not in where you run this java program
3 , When you run the program make sure you are sending the file path based on the Environment(Windows,unix etc.....)
4 , check File availability first
try
{
File f = new File("c:\fake path\db.sql");
if(f.exists())
{
//read the file
}
}
catch(Exception e)
{
// do some work
}
I have the following function inside a Stateless EJB running in Glassfish. All it does is write some data to a file. The first part of the function just creates the path to where the file needs to go. The second part actually writes the file.
private boolean createFile(String companyName, String fileName, byte[] data)
{
logger.log(Level.FINEST, "Creating file: {0} for company {1}", new Object[]{fileName, companyName});
File companyFileDir = new File(LOCAL_FILE_DIR, companyName);
if(companyFileDir.exists() == false)
{
boolean createFileDir = companyFileDir.mkdirs();
if(createFileDir == false)
{
logger.log(Level.WARNING, "Could not create directory to place file in");
return false;
}
}
File newFile = new File(companyFileDir, fileName);
try
{
FileOutputStream fileWriter = new FileOutputStream(newFile);
fileWriter.write(data);
}
catch(IOException e)
{
logger.log(Level.SEVERE,"Could not write file to disk",e);
return false;
}
logger.log(Level.FINEST,"File successfully written to file");
return true;
}
The output I get after this code executes is:
WARNING: Could not create directory to place file in
So obviously Glassfish cant create this directory. I am am assuming this has something to do with permissions. Can anyone give me a direction to go as to what might be wrong here?
I am running this on Glassfish 3.12 on Ubuntu 12
different things:
1) Compare spec: (21.1.2 Programming Restrictions)
An enterprise bean must not use the java.io package to attempt to access files and directories in the file system.
I'm sure GF isn't enforcing this, but you should be aware of that.
2) The code itself is fine. Try chmod +777 on the LOCAL_FILE_DIR to get an idea if it has to do with rights in general ...
Hope that helps ...