Java Tutorial/File/BufferedInputStream

BufferedInputStream

For faster reading you should use BufferedInputStream to wrap any InputStream. BufferedInputStream has two constructors that accept an InputStream:

   <source lang="java">

public BufferedInputStream(InputStream in) public BufferedInput Stream (Input Stream in, int bufferSize)</source>

Then, instead of calling the methods on fis, work with the BufferedInputStream bis.

Buffered Stream Copier

   <source lang="java">

import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class MainClass {

 public static void main(String[] args) {
   try {
     copy(System.in, System.out);
   } catch (IOException ex) {
     System.err.println(ex);
   }
 }
 public static void copy(InputStream in, OutputStream out) throws IOException {
   BufferedInputStream bin = new BufferedInputStream(in);
   BufferedOutputStream bout = new BufferedOutputStream(out);
   while (true) {
     int datum = bin.read();
     if (datum == -1)
       break;
     bout.write(datum);
   }
   bout.flush();
 }

}</source>

Import a file of exported preference data.

   <source lang="java">

import java.io.BufferedInputStream; import java.io.FileInputStream; import java.io.InputStream; import java.util.prefs.Preferences; public class Main {

 public static void main(String[] argv) throws Exception {
   // Create an input stream on a file
   InputStream is = new BufferedInputStream(new FileInputStream("output.xml"));
   // Import preference data
   Preferences.importPreferences(is);
 }

}</source>

Read File in String Using Java BufferedInputStream Example

   <source lang="java">

import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; public class Main {

 public static void main(String[] args) throws Exception {
   File file = new File("C:/ReadFile.txt");
   FileInputStream fin = new FileInputStream(file);
   BufferedInputStream bin = new BufferedInputStream(fin);
   byte[] contents = new byte[1024];
   int bytesRead = 0;
   String strFileContents;
   while ((bytesRead = bin.read(contents)) != -1) {
     strFileContents = new String(contents, 0, bytesRead);
     System.out.print(strFileContents);
   }
   bin.close();
 }

}</source>

Read File Using Java BufferedInputStream Example

   <source lang="java">

import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; public class Main {

 public static void main(String[] args) throws Exception {
   File file = new File("C:/ReadFile.txt");
   FileInputStream fin = new FileInputStream(file);
   BufferedInputStream bin = new BufferedInputStream(fin);
   while (bin.available() > 0) {
     System.out.println((char) bin.read());
   }
   bin.close();
 }

}</source>

Read from file with BufferedInputStream

   <source lang="java">

import java.io.BufferedInputStream; import java.io.FileInputStream; public class Main {

 public static void main(String[] args) throws Exception {
   byte[] buffer = new byte[1024];
   BufferedInputStream bufferedInput = new BufferedInputStream(new FileInputStream("filename.txt"));
   int bytesRead = 0;
   while ((bytesRead = bufferedInput.read(buffer)) != -1) {
     String chunk = new String(buffer, 0, bytesRead);
     System.out.print(chunk);
   }
   bufferedInput.close();
 }

}</source>

Save keyboard input with BufferedInputStream

   <source lang="java">

import java.io.BufferedInputStream; import java.io.IOException; public class ConsoleInput {

 public static String readLine() {
   StringBuffer response = new StringBuffer();
   try {
     BufferedInputStream buff = new BufferedInputStream(System.in);
     int in = 0;
     char inChar;
     do {
       in = buff.read();
       inChar = (char) in;
       if ((in != -1) & (in != "\n") & (in != "\r")) {
         response.append(inChar);
       }
     } while ((in != -1) & (inChar != "\n") & (in != "\r"));
     buff.close();
     return response.toString();
   } catch (IOException e) {
     System.out.println("Exception: " + e.getMessage());
     return null;
   }
 }
 public static void main(String[] arguments) {
   System.out.print("\nWhat is your name? ");
   String input = ConsoleInput.readLine();
   System.out.println("\nHello, " + input);
 }

}</source>

Use buffered streams to copy a file

   <source lang="java">

import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; public class Main {

 public static void main(String[] argv) throws Exception {
   BufferedInputStream fin = new BufferedInputStream(new FileInputStream("in.dat"));
   BufferedOutputStream fout = new BufferedOutputStream(new FileOutputStream("out.dat"));
   int i;
   do {
     i = fin.read();
     if (i != -1)
       fout.write(i);
   } while (i != -1);
   fin.close();
   fout.close();
 }

}</source>