我应该如何引用java中的文本文件？

Question

I have to count the characters in a text file. I would like to do it with a for loop, however, I do not know how to refer to the length of the file?

public void countLetters(String) {
    for (int i = 0; i <      ; i++) {

    }
}

What should I write after the i < ?

Answer 1

Well you first need to read the contents of the file. You can do it the following manner.

FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);

Where file is the file object ie in your case, the text file which you want to read. Then read each line of the file, like this

String temp;
int totalNoOfCharacters = 0;
int noOfLines = 0;  //To count no of lines IF you need it
while ( (temp = br.readline()) != null ){
    noOfLines++;
    totalNoOfCharacters += temp.length(); //Rememeber this doesnot count the line termination character. So if you want to consider newLine as a character, add one in this step.
}

Answer 2

FileReader fr = new FileReader("pathtofile");
BufferedReader br = new BufferedReader(fr);
String line = "";
int cont=0;

while ((line = br.readLine()) != null) {
line = line.split("\\s+").trim();
cont+=line.length();
}

Don't forget to close streams and use try catch .

Answer 3

Maybe better to read each each character within a while loop that first checks for the end of the file than to try using a for loop. eg

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

. . . .
. . . .

try
{
   BufferedReader reader = new BufferedReader(new FileReader("myFile.txt"));
   String textLine = reader.readLine();
   int count = 0;
   while (textLine != null)
   {
      textLine.replaceAll("\\s+",""); // To avoid counting spaces
      count+= textLine.length();
      textLine = reader.readLine();
   }
   reader.close();
   System.out.println("Number of characters in myFile.txt is: " + count);
}

catch(FileNotFoundException e)
{
    System.out.println("The file, myFile.txt, was not found");          
}

catch(IOException e) 
{
    System.out.println("Read of myFile.txt failed.");
    e.printStackTrace();
}

Answer 4

  Scanner scanner = new Scanner(yourfile);
  while(scanner.hasNext()){
        word = scanner.next();
        char += word.length();
  }