Java tutorial
import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; public class Main { public static void main(String[] atgs) throws Exception { DataOutputStream out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("java.txt"))); out.writeUTF(""); out.writeBytes("a"); out.writeChars("aaa"); out.close(); DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream("java.txt"))); System.out.println(in.readUTF()); byte[] buf = new byte[1024]; int len = in.read(buf); System.out.println(new String(buf, 0, len)); in.close(); } }