package com.devcolibri.tools;

import java.io.*;

public class FileWorker {

    public static void write(String fileName, String textFromFile) {
        File file = new File(fileName);

        try {
            if(!file.exists()){
                file.createNewFile();
            }

            PrintWriter out = new PrintWriter(file.getAbsoluteFile());

            try {
                out.print(textFromFile);
            } finally {
                out.close();
            }
        } catch(IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static String read(String fileName) throws FileNotFoundException {
        StringBuilder sb = new StringBuilder();
        File file = new File(fileName);
        exists(fileName);

        try {
            BufferedReader in = new BufferedReader(new FileReader( file.getAbsoluteFile()));
            try {
                String s;
                while ((s = in.readLine()) != null) {
                    sb.append(s);
                    sb.append("\r\n");
                }
            } finally {
                in.close();
            }
        } catch(IOException e) {
            throw new RuntimeException(e);
        }
        return sb.toString();
    }

    public static void update(String nameFile, String newText) throws FileNotFoundException {
        exists(nameFile);
        StringBuilder sb = new StringBuilder();
        String oldFile = read(nameFile);
        sb.append(oldFile);
        sb.append(newText);
        write(nameFile, sb.toString());
    }

    public static void delete(String nameFile) throws FileNotFoundException {
        exists(nameFile);
        new File(nameFile).delete();
    }

    private static void exists(String fileName) throws FileNotFoundException {
        File file = new File(fileName);
        if (!file.exists()){
            throw new FileNotFoundException(file.getName());
        }
    }

}



package com.devcolibri.core;

import com.devcolibri.tools.FileWorker;

import java.io.FileNotFoundException;

/**
 * User: devcolibri.com
 */
public class WorkInFile {

    private static String text = "This new text2\nThis new text3\nThis new text4\n";
    private static String fileName = "D://Current tasks//STT//meeting_negotiations_corpus_material//info_files//1406901600000.info";
    private static String fileNameFinal = "D://Current tasks//STT//meeting_negotiations_corpus_material//info_files//1406901600000.info";

    public static void main(String[] args) throws FileNotFoundException {

        //Чтение файл
        String textFromFile = FileWorker.read(fileName);
        System.out.println(textFromFile);


        //Запись в файл
        FileWorker.write(fileNameFinal, textFromFile);


        //Обновление файла
        FileWorker.update(fileNameFinal, "This new text");

        //Попытка прочитать не существующий файл
        //FileWorker.read("no_file.txt");





        //Удаление файла
       // FileWorker.delete(fileName);
    }


}