FIO Hello World for workshop

File IO Hello World

package csc171.workshop;

import java.io.*;

public class Main {

    public static void main(String[] args) throws IOException, FileNotFoundException {
        // P1
        writeHelloWorld();
        readHelloWorld();
          
        // P2
        writeHelloWorldSafely();
        readHelloWorldSafely();
    }
    
    public static void writeHelloWorld() throws IOException, FileNotFoundException {

        String filename = "abc.txt";
        File file = new File(filename);
        OutputStream os = null;

        os = new FileOutputStream(file);
        os.write("Hello World!".getBytes());

        os.close();
    }

    public static void readHelloWorld() throws IOException, FileNotFoundException {

        String filename = "abc.txt";
        File file = new File(filename);
        InputStream is = null;

        is = new FileInputStream(file);
        StringBuilder sb = new StringBuilder();

        int d = 64;
        while (d >= 64) {
            byte[] data = new byte[d];
            d = is.read(data, 0, 64);
            sb.append(new String(data));
        }

        System.out.println(sb);
        
        is.close();
    }

    public static void writeHelloWorldSafely() {

        String filename = "abc.txt";
        File file = new File(filename);
        OutputStream os = null;

        try {
            os = new FileOutputStream(file);
            os.write("Hello World!".getBytes());
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            closeSafely(os);
        }
    }

    public static void readHelloWorldSafely() {

        String filename = "abc.txt";
        File file = new File(filename);
        InputStream is = null;

        try {
            is = new FileInputStream(file);
            StringBuilder sb = new StringBuilder();

            int d = 64;
            while (d >= 64) {
                byte[] data = new byte[d];
                d = is.read(data, 0, 64);
                sb.append(new String(data));
            }

            System.out.println(sb);

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            closeSafely(is);
        }
    }

    public static void closeSafely(Closeable closeable) {
        if (closeable != null) {
            try {
                closeable.close();
            } catch (Exception e) {
                // Squash
            }
        }
    }
}