Although file(deneme.txt) is in the same src file with runner class. Why cannot I use just file name?
import java.io.File;
public class Runner {
public static void main(String []args) {
//File file = new File("deneme.txt");
File file = new File("C:\\Users\\serha\\eclipse-workspace\\HW1\\src\\deneme.txt");
System.out.println(file.exists());
System.out.println(file.isFile());
}
}
Related
I'm trying to read a plain text file but somehow FileReader is not finding my text file. I checked the directory using getAbsolutefile() and /Users/djhanz/IdeaProjects/datalab2/pg174.txt is the exact location of the file. I tried datlab2/pg174.txt and everything I possibly could.
Here is my code
public class Program1 {
public static void main(String[] args) {
System.out.println(new File("pg174.txt").getAbsoluteFile());
Scanner testScanner = new Scanner(new BufferedReader(new FileReader("/Users/djhanz/IdeaProjects/datalab2/pg174.txt")));
while (testScanner.hasNextLine())
{
System.out.println(testScanner.nextLine());
}
}
}
The text file is under the same project directory called datalab.
Can someone please enlighten me?
Use Scanner testScanner = new Scanner(new BufferedReader(new FileReader("/pg174.txt")));
FileReader("/pg174.txt") instead of FileReader("pg174.txt").
package com.example.demo;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.Scanner;
public class Program1 {
public static void main(String[] args) throws FileNotFoundException {
System.out.println(new File("pg174.txt").getPath());
System.out.println(new File("pg174.txt").getAbsoluteFile());
System.out.println(new File("pg174.txt").getAbsolutePath());
Scanner testScanner = new Scanner(new BufferedReader(new FileReader("/pg174.txt")));
while (testScanner.hasNextLine()) {
System.out.println(testScanner.nextLine());
}
}
}
Output:
We want to prevent other processes from deleting the temp directory of our running application. That way we create a temp directory and a lock file in it. The only way I found at that prevents deleting this file is by using RandomAccessFile:
tempDirectory = Files.createTempDirectory("myapp");
final Path lockFile = Files.createTempFile(tempDirectory, "lock", null);
randomAccessFile = new RandomAccessFile(lockFile.toFile(), "rw");
Is there a way to achieve the same with nio? I have tried with the following code:
import java.io.*;
import java.nio.channels.*;
import java.nio.file.*;
public class CreateLock {
public static void main(String[] args) throws IOException, InterruptedException {
final Path path = Paths.get("C:/temp/test");
Files.createFile(path);
final FileChannel channel = FileChannel.open(path, StandardOpenOption.WRITE);
channel.lock();
for (int i = 60; i-- > 0; ) {
System.out.println(i);
if (!Files.isRegularFile(path)) {
System.out.println("File is gone");
break;
}
Thread.sleep(10_000);
}
channel.close();
}
}
but a second Java application with this code
import java.io.*;
import java.nio.file.*;
public class DeleteLock {
public static void main(String[] args) throws IOException {
final Path path = Paths.get("C:/temp/test");
Files.delete(path);
}
}
can delete the file.
Please try below:
FileChannel ch = FileChannel.open(lockFile.toAbsolutePath(), StandardOpenOption.WRITE);
ch.lock();
On the same directory of my Main.java file, I have a package/folder named database, and inside the database package I have a file named Data.txt.
This is my code of Main.java, but it is throwing this error:
java: exception java.io.FileNotFoundException
How can I get the file from a relative file? I'm used to web development, and usually something with a . dot like "./folder/file.txt" works.
import java.io.File;
import java.util.Scanner;
import java.io.FileNotFoundException;
public class Main {
public static void main(String[] args) {
readFile();
}
public static void readFile() {
File file = new File("./database/Data.txt");
Scanner scanner = new Scanner(file);
try {
while (scanner.hasNextLine()) {
int i = scanner.nextInt();
System.out.println(i);
}
scanner.close();
}
catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
You are not importing FileNotFoundException class. also, scanner statement throws the exception which should inside try. Solution is as below.
import java.io.File;
import java.util.Scanner;
import java.io.FileNotFoundException;
public class Main {
public static void main(String[] args) {
readFile();
}
public static void readFile() {
File file = new File("database/Data.txt");
try {
Scanner scanner = new Scanner(file);
while (scanner.hasNextLine()) {
int i = scanner.nextInt();
System.out.println(i);
}
scanner.close();
}catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
Only check if those content can read using scanner or not. Content having int properly. otherwise it will throw java.util.InputMismatchException.
Are you working on a mac or windows system.
I am on windows and ".\database\Data.txt" would most probably work depending on where the file is in your file structure.
Im trying to use relative path to read a file but the path cant be found.
maxSuccession is the name of my project
This is my workspace path: C:\Programming
This is my project's path C:\Programming\MaxSuccessions\maxSuccessions
This is my filepath C:\Programming\MaxSuccessions\Tests\test1\00.in.txt
package test1;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Scanner;
public class test1 {
public static void main(String[] args) throws IOException {
String myPath="..\\MaxSuccessions\\Tests\\test1\\";
Scanner sc = new Scanner(new File(myPath+"00.in.txt"));
System.out.println(sc.nextInt());
}
}
If your class file and required file are in the same directory, you can try this code:
public static void main(String[] args) {
String fileName = "00.in.txt"; //relative path from the path of your class.
try {
Scanner sc = new Scanner(Test.class.getResource(fileName).openStream());
System.out.println(sc.nextInt());
} catch (IOException e) {
e.printStackTrace();
}
}
I have most of it down but when I try to make the copy, no copy is made.
It finds the files in the specified directory like it is supposed to do and I think the copy function executes but there aren't any more files in the specified directory. Any help is appreciated. I made a printf function that isn't shown here. Thanks!
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.Scanner;
import org.apache.commons.io.FilenameUtils;
import org.apache.commons.io.FileUtils;
import static java.nio.file.StandardCopyOption.*;
public class Stuff {
static String path, oldExtn, newExtn;
static Boolean delOrig = false;
private static void getPathStuff() {
printf("Please enter the desired path\n");
Scanner in = new Scanner(System.in);
path = in.next();
printf("Now enter the file extension to replace\n");
oldExtn = in.next();
printf("Now enter the file extension to replace with\n");
newExtn = in.next();
in.close();
}
public static void main(String[] args) {
getPathStuff();
File folder = new File(path);
printf("folder = %s\n", folder.getPath());
for (final File fileEntry : folder.listFiles()) {
if (fileEntry.getName().endsWith(oldExtn)) {
printf(fileEntry.getName() + "\n");
File newFile = new File(FilenameUtils.getBaseName(fileEntry
.getName() + newExtn));
try {
printf("fileEntry = %s\n", fileEntry.toPath().toString());
Files.copy(fileEntry.toPath(), newFile.toPath(),
REPLACE_EXISTING);
} catch (IOException e) {
System.err.printf("Exception");
}
}
}
}
}`
The problem is that the new file is created without a full path (only the file name). So your new file is created - only not where you expect...
You can see that it'll work if you'll replace:
File newFile = new File(FilenameUtils.getBaseName(fileEntry
.getName() + newExtn));
with:
File newFile = new File(fileEntry.getAbsolutePath()
.substring(0,
fileEntry.getAbsolutePath()
.lastIndexOf(".")+1) + newExtn);