I dont really know how to express my words but here's the output example.
Please enter the desired folder: c:/Test
a.txt b.txt c.txt d.txt
Enter the name of the file that you want to run: a.txt
Hello Java!
And if I put the file with nothing in it, the output will be
The file is empty. Start again.
You are so lazy to google the basics.
I'll help you:
1. Get directory content:How to get contents of a folder and put into an ArrayList
2. Output file content: How do you read a text file and print it to the console window? Java and How to write console output to a txt file
Consider googling an 'if-else' situations.
Hope this will help!
Assuming you want to take console input and read ONLY txt files, you can try the following
Read Contents from File (if present)
public static void main(String... s)throws IOException {
String folderName = "C://Test//";
Scanner sc = new Scanner(System.in);
String fileName = sc.nextLine();
File file = new File(folderName+fileName);
if(file.exists() && file.isFile() && file.length() > 0) {
BufferedReader br = new BufferedReader(new FileReader(file));
String line = br.readLine();
while(line != null) {
System.out.println(line);
line = br.readLine();
}
br.close();
} else {
System.out.println("This file is empty. Start again");
}
}
Display hello java if file is found
public static void main(String... s)throws IOException {
String folderName = "C://Test//";
Scanner sc = new Scanner(System.in);
String fileName = sc.nextLine();
File file = new File(folderName+fileName);
if(file.exists() && file.isFile() && file.length() > 0) {
System.out.println("Hello Java!");
} else {
System.out.println("This file is empty. Start again");
}
}
The program will run, and you can input your desired filename (with .txt extension)
