//: NewIODemo.java * Java 1.1 IO typical usage import java.io.*; public class NewIODemo { public static void main(String args[]) { try { // 1. Reading input by lines: BufferedReader in = new BufferedReader( new FileReader(args[0])); String s, s2 = new String(); while((s = in.readLine())!= null) s2 += s + "\n"; in.close(); // 1b. Reading standard input: BufferedReader stdin = new BufferedReader( new InputStreamReader(System.in)); System.out.print("Enter a line:"); System.out.println(stdin.readLine()); // 2. Input from memory StringReader in2 = new StringReader(s2); int c; while((c = in2.read()) != -1) System.out.println((char)c); // 3. Formatted memory input try { DataInputStream in3 = new DataInputStream( // Oops: must use deprecated class: new StringBufferInputStream(s2)); while(true) System.out.print((char)in3.readByte()); } catch(EOFException e) { System.out.println("End of stream"); } // 4. Line numbering & file output try { LineNumberReader li = new LineNumberReader( new StringReader(s2)); BufferedReader in4 = new BufferedReader(li); PrintWriter out1 = new PrintWriter( new BufferedWriter( new FileWriter("IODemo.out"))); while((s = in4.readLine()) != null ) out1.println( "Line " + li.getLineNumber() + s); out1.close(); } catch(EOFException e) { System.out.println("End of stream"); } // 5. Storing & recovering data try { DataOutputStream out2 = new DataOutputStream( new BufferedOutputStream( new FileOutputStream("Data.txt"))); out2.writeBytes( "Here's the value of pi: \n" ); out2.writeDouble(3.14159); out2.close(); DataInputStream in5 = new DataInputStream( new BufferedInputStream( new FileInputStream("Data.txt"))); BufferedReader in5br = new BufferedReader( new InputStreamReader(in5)); // Can now use the "proper" readLine(): System.out.println(in5br.readLine()); // Must use DataInputStream elswhere: System.out.println(in5.readDouble()); } catch(EOFException e) { System.out.println("End of stream"); } // 6. Reading and writing random access // files is the same as before. } catch(FileNotFoundException e) { System.out.println( "File Not Found:" + args[1]); } catch(IOException e) { System.out.println("IO Exception"); } } ///:~