IST 256 Application Programming for Information Systems Xiaozhong Liu Yatish Hegde

Hard Disk (Secondary Memory) Memory (Primary Memory) Read Write Process

Input Stream Output Stream Default input/output streams

JAVA provides 2 types of streams Text streams - containing ‘characters‘ I ‘M A STRING\n ProgramDevice Binary Streams - containing 8 – bit information ProgramDevice

Create a stream object and associate it with a disk-file Give the stream object the desired functionality while there is more information read(write) next data from(to) the stream close the stream

public static void readFile() { BufferedReader ins = new BufferedReader(new FileReader(“test.txt”)); while(ins.ready()) { String s = ins.readLine(); System.out.println(s); } ins.close(); } Important: Place the code inside Try{…} Catch{….} Wherever necessary import java.io.*;

public static void writeFile() { String s = “I love programming”; BufferedWriter outs = new BufferedWriter(new FileWriter(“test_out.txt”)); outs.write(s); } outs.close(); Important: Place the code inside Try{…} Catch{….} Wherever necessary import java.io.*;

Public static void readFile() { BufferedReader ins = new BufferedReader(new FileReader(“test.txt”)); Scanner scanner = new Scanner(ins); while(scanner.hasNext()) { System.out.println(scanner.next()); } scanner.close(); } Important: Place the code inside Try{…} Catch{….} Wherever necessary import java.io.*; Import java.util.Scanner;

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) { JFileChooser fc = new JFileChooser(); if(fc.showOpenDialog(this) == JFileChooser.APPROVE_OPTION) { File file = fc.getSelectedFile(); String inputFilePath = file.getAbsolutePath().toString(); jTextField1.setText(inputFilePath); }

 In a notepad, type few sentences and save the file as test.txt. Write a Java program to read the text in test.txt and write that to file test_out.txt.  In a notepad, type 10 numbers (any numbers in the range 0 to 10) separated by white space and save the file as grade.txt. Write a Java program to read the numbers from grade.txt, calculate the average grade and print the output.  In a notepad, type five names (one name per line) and save the file as name.txt. Create a GUI from which you can select (browse button) the file name.txt and write (create button) the names in name.txt to file name_out.txt (one name per line).