Java|Scala IO

JavaScalaIO

Java

Write serialized object to a file
public static void writeFile(File dest) throws IOException{
	FileOutputStream fileStream = new FileOutputStream(dest);
	ObjectOutputStream os = new ObjectOutputStream(fileStream);
	os.writeObject(obj);
	os.close();
}

Read serialized object from a file
public static void writeFile(File source) throws IOException{
	FileInputStream fileStream = new FileInputStream(source);
	ObjectInputStream os = new ObjectInputStream(fileStream);
	Object obj = os.readObject();
	MyObj myObj = (MyObj) obj;
	os.close();
}

Write text to a file
public static void writeFile(File source) throws IOException{
	FileWriter writer = new FileWriter(source);
	writer.write("How we write a text file in java");
	writer.close();
}

Read text from a file
public static void main(File source) throws IOException{
	BufferedReader reader = new Buffered Reader(new FileReader(source));
	String line = null;
	while((line = reader.readLine()) != null){
		System.out.println(line);
	}
	reader.close();
}

Copy file via binary read/write
private static void copyFile(File source, File dest) throws IOException {
    OutputStream out = new FileOutputStream(dest);
    byte[] buffer = new byte[(int) source.length()];
    FileInputStream in = new FileInputStream(source);
    in.read(buffer);
    try {
        out.write(buffer);
    } finally {
        out.close();      
        in.close();
    }
}


Scala

Read text from file
for(line <- io.Source.fromFile(filename).getLines) println(line)

Write text to a file
val out = new PrintWriter(filename)
for (i <- 1 to 100) out.println(i)
out.close()

Read binary file
val in = new FileInputStream(new File(filename))
val bytes = new Array[Byte](file.length.toInt)
in.read(bytes)
in.close()