Program for counting the number of lines in the * .txt file - Java

Question

Hi, I actually wrote the code of the program that does the following - the user writes the * .txt file path, the program calculates how many lines in the document, displays the number of lines on the screen + creates a * .txt file in which also writes the number of lines. Here is the code, use:

public class GetStrings { public static void main(String[] args) { System.out.println("Введите абсолютный путь к файлу: "); Scanner scanner = new Scanner(System.in); String inputValue = scanner.next(); String n = inputValue; try { File myFile = new File(n); FileReader fileReader = new FileReader(myFile); LineNumberReader lineNumberReader = new LineNumberReader(fileReader); int lineNumber = 0; while (lineNumberReader.readLine() != null) { lineNumber++; } System.out.println(lineNumber); lineNumberReader.close(); String lineNumber1 = String.valueOf(lineNumber); File newFile = new File("d:\\myFile.txt"); FileWriter fileWriter = new FileWriter(newFile); fileWriter.write(lineNumber1 + " Строк в файле: " + n); fileWriter.close(); } catch (IOException e) { e.printStackTrace(); } } }

And now I decided to make the user write the directory, the program looked at the directory for the presence of the * .txt extension files and read the lines in each of the documents, display all the values on the screen and also write them to the new * .txt file. I wrote the code to read files in a directory, but I cannot pull out every variable in the file in a directory to count the number of lines. Here is the time, but how to connect it, help)):

 public class Blabla { public static void main(String[] args) { System.out.println("Введите абсолютный путь: "); Scanner scanner = new Scanner(System.in); String inputValue = scanner.next(); String n = inputValue; File folder = new File(n); final String[] extension = {".txt"}; String[] files = folder.list(new FilenameFilter() { @Override public boolean accept(File folder, String name) { for(String ext : extension) if(name.toLowerCase().endsWith(ext)) return true; return false; } }); for(String fileName : files) try { FileReader fileReader = new FileReader(fileName); LineNumberReader lineNumberReader = new LineNumberReader(fileReader); int lineNumber = 0; while (lineNumberReader.readLine() != null) { lineNumber++; } System.out.println(lineNumber); lineNumberReader.close(); String lineNumber1 = String.valueOf(lineNumber); File newFile = new File("d:\\myFile.txt"); FileWriter fileWriter = new FileWriter(newFile); fileWriter.write(lineNumber1 + " Строк в файле: " + n); fileWriter.close(); System.out.println("File: " + fileName); } catch (IOException e) { e.printStackTrace(); } } }

@RomanC I can not pull out the variables of each file, to hold over them the function of counting the number of lines
declare the class variable and put your files in there, no matter what the counting function is, it didn’t write it anyway.
But how can I pull out every element that finds it in the files variable and perform an operation on it I can’t understand ..
an element must have a type, without understanding this you will fail

Victor Victor 4,690 2 7 28 · Answer 1 · 2017-11-14T00:08:04

It looks like a learning task, so I will propose a verbal algorithm:

We receive the address from the user
Check whether this directory (File.isDirectory)
If this is a folder, then we take all its folders and go through them. At each attached file we check: 3.1. If the file is a directory, recursively return to the beginning of p.3 3.2. If the file is a file, check the extension, and if txt, then put in the sheet
At output p3 we get a list of files with the extension txt
Go through all the txt files and count the lines
Print the number of lines.

If you dig a little, you can use Files.walkFileTree (), which will do points 1-3 for you.

Why did you write down on points what I wrote in the description and in the comments below?

diraria 8,329 four 14 45 · Answer 2 · 2017-11-13T22:56:37

 import java.io.File; import java.io.FileReader; import java.io.FileWriter; import java.io.FilenameFilter; import java.io.IOException; import java.io.LineNumberReader; import java.util.Scanner; import java.util.logging.Level; import java.util.logging.Logger; public class Blabla { public static void main(String[] args) { System.out.println("Введите абсолютный путь: "); Scanner scanner = new Scanner(System.in); String inputValue = scanner.next(); File folder = new File(inputValue); final String[] extension = {".txt"}; File[] files = folder.listFiles(new FilenameFilter() { @Override public boolean accept(File folder, String name) { for (String ext : extension) { if (name.toLowerCase().endsWith(ext)) { return true; } } return false; } }); StringBuilder sb = new StringBuilder(); for (File fileName : files) { try { FileReader fileReader = new FileReader(fileName); LineNumberReader lineNumberReader = new LineNumberReader(fileReader); int lineNumber = 0; while (lineNumberReader.readLine() != null) { lineNumber++; } lineNumberReader.close(); sb.append(lineNumber).append(" Строк в файле: ").append(fileName).append("\r\n"); System.out.println(lineNumber); System.out.println("File: " + fileName); } catch (IOException e) { Logger.getLogger(Blabla.class.getName()).log(Level.SEVERE, null, e); } } File newFile = new File("d:\\myFile.txt"); try { FileWriter fileWriter = new FileWriter(newFile); fileWriter.write(sb.toString()); fileWriter.close(); } catch (IOException ex) { Logger.getLogger(Blabla.class.getName()).log(Level.SEVERE, null, ex); } } }

if you understand your problem correctly, the solution looks like this
But here the problem is that the file is constantly being rewritten, so it only records the last value, not all files
@ 269255 myFile.txt, as I understand it, it is just re-created for each file, and since the name myFile.txt is the same, it just overwrites, well, it stops at the last value
Well, of course, if you turn FileWriter in a loop, along with a collection of your files, write a new file each time ... you need to take it out of the loop and everything is ok.

Program for counting the number of lines in the * .txt file - Java

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