Запись в файл на сервере из jsp

....
 
if (request.getParameter('saveToFile') != null) {
    ServletContext app = getServletContext();
    String appRootPath = app.getRealPath('.');
    writeFile tt = new writeFile(appRootPath);
    tt.writeToStream('Name: ' + user.getUsername() + '
');
    tt.writeToStream('E-mail: ' + user.getEmail() + '
');
    tt.closeStream();
}
 
....

import java.io.*;
 
public class writeFile {
    File testFile;
    FileOutputStream stream;
    
    public writeFile(String s) {
        testFile = null;
        stream = null;
        System.out.println('file created');
        testFile = new File(s + 'testfile.txt');    
        try {
            System.out.println('open stream');
            stream = new FileOutputStream(testFile);
        }
        catch (FileNotFoundException e) {
            System.exit(0);
        }
    }
    //try to write
    public void writeToStream(String s) throws IOException{
        System.out.println('*** Try to write file');
        byte[] ba = new byte[s.length()];
        ba = s.getBytes();
        stream.write(ba);
    }
    public void closeStream() throws IOException {
        stream.close();
        System.out.println('*** Stream closed');
    }
}

import java.io.*;
 
public class writeFile {
    File testFile;
    FileOutputStream stream;
    
    public writeFile(String s) {
        testFile = null;
        stream = null;
        System.out.println('file created');
        testFile = new File(s + 'testfile.txt');
        if (testFile.canWrite()) {
            try {
                //System.out.println('open stream');
                stream = new FileOutputStream(testFile);
            }
            catch (FileNotFoundException e) {
                //System.out.println('FileNotFoundException');
            }
        }
    }
    //try to write
    public void writeToStream(String ss) throws IOException{
        //System.out.println('*** Try to write file');
        byte[] ba = new byte[ss.length()];
        ba = ss.getBytes();
        try {
            stream.write(ba);
        }
        catch (IOException e) {
            //
        }
    }
    public void closeStream() throws IOException {
        stream.close();
        //System.out.println('*** Stream closed');
    }
}

import java.io.*;
 
public class writeFile {
    File testFile;
    FileOutputStream stream;
    
    public writeFile(String s) {
        testFile = null;
        stream = null;
        System.out.println('file created');
        testFile = new File(s + 'testfile.txt');
        /*
        if (testFile.exists()) {
            System.out.println('File does not exists');
        }
        else System.out.println('File exists');
        if (testFile.canRead()) {
            System.out.println('testFile.canRead() is true');
        }
        else System.out.println('testFile.canRead() is false');
        if (testFile.canWrite()) {
            System.out.println('testFile.canWrite() is true');
        }
        else System.out.println('testFile.canWrite() is false');
        */
        try {
            System.out.println('open stream');
            stream = new FileOutputStream(testFile);
            if (stream.getFD().valid() != true) System.out.println('can't open stream');
        }
        catch (FileNotFoundException e) {
            System.out.println('FileNotFoundException');
            e.printStackTrace();
        }
        catch(IOException e) {
            e.printStackTrace();
        }
    }
    //try to write
    public void writeToStream(String ss) throws IOException{
        System.out.println('*** Try to write file');
        byte[] ba = new byte[ss.length()];
        ba = ss.getBytes();
        try {
            //throw new java.lang.NullPointerException();
            stream.write(ba);
        }
        catch (java.lang.NullPointerException e) {
            System.out.println('java.lang.NullPointerException was thrown and catched');
            e.printStackTrace();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }
    public void closeStream() throws IOException {
        stream.close();
        System.out.println('*** Stream closed');
    }
}