Ioproov.java
Allikas: Lambda
// Vaike demo failist ridade kaupa lugemise kohta, // mis lihtsalt kopeerib faili. // // NB! Vt teisi naiteid Ecki opik sektsioon 10.3 // // Olulist tahele panna: // - Programm loeb kasurealt sisendfaili ja valjundfaili nimed // - Valjundfaili kirjutatakse read, tapselt nagu sisendist loetud // - Kui valjundfail oli varem juba olemas, siis programm ei tee koopiat ja peatub. // - Rea kaupa lugemiseks kasutab BufferedReader klassist funktsiooni readLine // - Trykkimiseks kasutatav println on sama, mis System.out jaoks println, ainult // et valjund laheb avatud faili, mis on System.out asemel. // - Avatud failid tuleb peale nende kasutamist sulgeda // Must import java.io.* in order to get access to libraries import java.io.*; public class ioproov { public static void main(String[] args) { String sourceName; String copyName; /* Get two file names from the command line. If the command line does not have a legal form, print an error message and end this program. */ if (args.length == 2) { sourceName = args[0]; copyName = args[1]; } else { System.out.println("Usage: java ioproov <source-file> <copy-name>"); return; } /* If the output file already exists, print an error message and end the program. */ File file = new File(copyName); if (file.exists()) { System.out.println("Output file exists. Exiting."); return; } // All file I/O operations must be done within a try/catch statement try { // Set up the proper readers and writers FileReader file_reader = new FileReader(sourceName); FileWriter file_writer = new FileWriter(copyName); BufferedReader br_reader = new BufferedReader(file_reader); PrintWriter pr_writer = new PrintWriter(file_writer); // Get the first line of the file String line = br_reader.readLine(); // check to see if it is null - end of file while (line != null) { // print line to output file pr_writer.println(line); // get next line of input file line = br_reader.readLine(); } // while loop // Finally you must close input and output streams! file_reader.close(); file_writer.close(); } //try // catch any exceptions thrown catch (IOException e) { //print error and exit program System.out.println(e); System.exit(1); } } }