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About Ilias Tsagklis

Ilias Tsagklis
Ilias is a senior software engineer working in the telecom domain. He is an applications developer in a wide variety of applications/services, currently the technical lead in a in-house PCRF solution. Particularly interested in multi-tier architecture, middleware services and mobile development (contact). Ilias Tsagklis is co-founder and Executive Editor at Java Code Geeks.

Read file with FileInputStream

With this example we are going to demonstrate how to read a File with a FileInputStream. The FileInputStream obtains input bytes from a file in a file system. In short, to read a File with a FileInputStream you should:

  • Create a new File instance by converting the given pathname string into an abstract pathname.
  • Create a FileInputStream by opening a connection to an actual file, the file named by the path name name in the file system.
  • Create a StringBuffer with no characters in it and an initial capacity of 16 characters.
  • Read data from the file using read() API method of FileinputStream and append it to the StringBuffer, using append(char c) API method of StringBuffer.
  • Close the stream using close() API method.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class ReadFileWithFileInputStream {

public static void main(String[] args) {
		File file = new File("inputfile.txt");
		FileInputStream fin = null;
		int ch;
		StringBuffer sb = new StringBuffer();

		try {			
			// create FileInputStream object
			fin = new FileInputStream(file);
			// Read bytes of data from this input stream
			while((ch = fin.read()) != -1) {
			System.out.println("File content: " + sb);
		catch (FileNotFoundException e) {
			System.out.println("File not found" + e);
		catch (IOException ioe) {
			System.out.println("Exception while reading file " + ioe);
		finally {
			// close the stream using close method
			try {
				if (fin != null) {
			catch (IOException ioe) {
				System.out.println("Error while closing stream: " + ioe);

This was an example of how to read a File with a FileInputStream in Java.

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