Computer-Masters.net > Articles > Programming > Java > Java: Reading a file line by line with BufferedReader

Java: Reading a file line by line with BufferedReader

Buffered Reader Example

When using text files in a programm the most common use case is to read it line by line. The Java library provides the BufferedReader for this use case.

Learn by this code example how to use the BufferedReader for reading a text file.

Example Code


Java Code

        BufferedReader bufferedReader = null;
        //The path to your text file
        String filePath ="C:/example.txt";
        File file = new File(filePath);
        try {
            //BufferedReader needs a FileReader. 
            //You can create this while constructing
            bufferedReader = new BufferedReader(new FileReader(file));
          String line;
          //returns null if EOF (End of File) or Error
          while (null != (line = bufferedReader.readLine())) {
            //Print line on the console
            System.out.println(line);
            //Do your work here ....
          }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
          if (null != bufferedReader) {
            try {
              bufferedReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
          }
        }
1

The above code prints out C:\example.txt to the console.

With bufferedReade.readLine() one line is read from the file and returned as String. null is returned if EOF (End of File) is reached or an error occurs.

Be aware to catch the I/O-Exceptions properly. You should not ignore them or leave them out when working with files.

bufferedReader.close() closes the bufferedReader. This should be done in the finally clause to ensure it is also executed if an error (Exception) occurs. It can happen that bufferedReader never got instantiated when you try it to close in the finally clause. Therefore you need to check for null before closing it to avoid a NullPointerException in your finally clause.

 

You will need these imports in your Java program from java.io:


Java Code

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
1

 

You still have questions?

Feel free to use our comment form that is also available for non-registered users.

The Terms of Use and Posting Guidelines apply.

 

Comments

Computer-Masters.net > Articles > Programming > Java > Java: Reading a file line by line with BufferedReader

Advertisement: