import java.io.*; public class main { public static void main(String[] args) throws IOException { String s = loadTextFile("input/main.java", ""); s = s.replaceAll("for i=1, 10 \\{", "for (int i = 1; i <= 10; i++) {"); saveTextFile("output/main.java", s); } static String charsetForTextFiles = "UTF-8"; public static String loadTextFile(String fileName, String defaultContents) throws IOException { if (!new File(fileName).exists()) return defaultContents; FileInputStream fileInputStream = new FileInputStream(fileName); InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, charsetForTextFiles); return loadTextFile(inputStreamReader); } public static String loadTextFile(Reader reader) throws IOException { StringBuilder builder = new StringBuilder(); try { BufferedReader bufferedReader = new BufferedReader(reader); String line; while ((line = bufferedReader.readLine()) != null) builder.append(line).append('\n'); } finally { reader.close(); } return builder.length() == 0 ? "" : builder.substring(0, builder.length()-1); } /** writes safely (to temp file, then rename) */ public static void saveTextFile(String fileName, String contents) throws IOException { File file = new File(fileName); File parentFile = file.getParentFile(); if (parentFile != null) parentFile.mkdirs(); String tempFileName = fileName + "_temp"; FileOutputStream fileOutputStream = new FileOutputStream(tempFileName); OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream, charsetForTextFiles); PrintWriter printWriter = new PrintWriter(outputStreamWriter); printWriter.print(contents); printWriter.close(); if (file.exists() && !file.delete()) throw new IOException("Can't delete " + fileName); if (!new File(tempFileName).renameTo(file)) throw new IOException("Can't rename " + tempFileName + " to " + fileName); } }