Java/JSP: Preserve line breaks while writing to a local file from string variables

Question

I need help to create read-write methods that write to a file and preserve the line breaks. The contents of the file are stored in a variable.

I use the following code to read a local HTML file:

public String scanLocalPage(String filePath) throws IOException
    {
        try{
       BufferedReader reader = new BufferedReader(new FileReader(filePath));
       StringBuilder sb = new StringBuilder();
       String line;

       while((line = reader.readLine())!= null){
                sb=sb.append(line);
       }


      reader.close();
       return sb.toString();
        }
        catch (Exception ee)
        {
            return "";
        }
    }

and the following method to write to a file:

public void writeToFile (String fileName, String fileContents) throws IOException
    {
        File outFile = new File (fileName);
        try (FileWriter fw = new FileWriter(outFile)) {
            fw.write(fileContents);
            fw.close();
        }  
    }

I use the above methods to read and write to a HTML file and a text file from String variables. The contents of the HTML file are generated in the code and the text file from a text area input field.

After writing to the file and then reading it again, the file contents are missing the line breaks. Any help to read/write with line breaks is appreciated.

Answer 1

You should use the system-dependent line separator string:

On UNIX systems, it returns "\\n"; on Microsoft Windows systems it returns "\\r\\n".

String newLine = System.getProperty("line.separator");
sb = sb.append(line).append(newLine);

If you are using Java 7 or greater, you can use the System.lineSeparator() method.

String newLine = System.lineSeparator();
sb = sb.append(line).append(newLine);

Answer 2

When you use readline() the line breaks are removed. You have to re-insert them with

sb = sb.append(line).append("\n");