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The Character Streams FileReader
Ramesh Fadatare edited this page Aug 19, 2018
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The FileReader class creates a Reader that you can use to read the contents of a file. FileReader is meant for reading streams of characters. For reading streams of raw bytes, consider using a FileInputStream.
- FileReader(File file) - Creates a new FileReader, given the File to read from.
- FileReader(FileDescriptor fd) - Creates a new FileReader, given the FileDescriptor to read from.
- FileReader(String fileName) - Creates a new FileReader, given the name of the file to read from.
- int read() - It is used to return a character in ASCII form. It returns -1 at the end of file.
- void close() - It is used to close the FileReader class.
The following example shows how to read lines from a file and display them on the standard output device. It reads its own source file, which must be in the current directory.
import java.io.FileReader; import java.io.IOException; /** * The class demonstrate the usage of FileReader class methods. * @author javaguides.net * */ class FileReaderDemo { public static void main(String args[]) { try (FileReader fr = new FileReader("FileReaderDemo.java")) { int c; // Read and display the file. while ((c = fr.read()) != -1) System.out.print((char) c); } catch (IOException e) { System.out.println("I/O Error: " + e); } } }
Note that this program reads its own source file, which must be in the current directory and produces below output:
package com.javaguides.javaio.book; import java.io.FileReader; import java.io.IOException; class FileReaderDemo { public static void main(String args[]) { try (FileReader fr = new FileReader("FileReaderDemo.java")) { int c; // Read and display the file. while ((c = fr.read()) != -1) System.out.print((char) c); } catch (IOException e) { System.out.println("I/O Error: " + e); } } }