I have a csv
file thats formatted like this id,text
. Here is an example:
helloText,How are you
goodbyeMessage,Some new text for a change
errorMessage,Oops something went wrong
Now lets say for example I want to edit the text part of goodbyeMessage
which is Some new text for change
, to See you later
The resulting csv
should then look like this:
helloText,How are you
goodbyeMessage,See you later
errorMessage,Oops something went wrong
I have code that can write to the file but when the code finishes executing, this is the resulting csv
file:
helloText,How are you
goodbyeMessage,Some new text for a change
errorMessage,Oops something went wronggoodbyeMessage,See you later
I know this is occurring because I set the FileWriter's append
value to true
. If I don't everything gets wiped.
I have tried using FileWriter.newLine()
to make it look better but that is not what I am trying to achieve. I still want the same number of line in the file.
MyApp.java
public static void main(String[] args) throws FileNotFoundException, IOException {
PropsWriter pw = new PropsWriter("test_props.txt");
pw.updateElementText("goodbyeMessage", "See you later");
}
PropsWriter.java
/**
* Updates the text of a given element in the properties file.
*
* @param id The id of the element
* @param newText The text that will replace the original text.
*
* @throws IOException If I/O error occurs
*/
public void updateElementText(String id, String newText) throws IOException {
Assertions.checkNotNull(id, "Id must not be null.");
Assertions.checkNotNull(id, "Id must not be an empty string.");
File file = new File(pathName);
BufferedReader br = new BufferedReader(new FileReader(file));
BufferedWriter wr = new BufferedWriter(new FileWriter(file, true));
try {
String line;
while((line = br.readLine()) != null) {
if(line.contains(id)) {
//returns true
System.out.println("Is line there: " + line.contains(id));
//returns helloText
System.out.println("ID: " + extractId(line));
//returns How are you
System.out.println("TEXT: " + extractText(line));
//returns Some new text for a change
System.out.println("NEW_TEXT: " + newText);
// This is where I am trying to replace the old text
// with new text that came from the main method.
line = line.replaceAll(extractText(line), newText);
//wr.newLine();
wr.write(line);
}
}
} catch(IOException e) {
e.printStackTrace();
} finally {
wr.close();
}
}
/**
* Gets the id part of a line that is stored in the
* properties file.
*
* @param element The element the id is got from.
* @return String representation of the id.
*/
private static String extractId(String line) {
final int commaOccurence = getFirstCommaOccurrence(line);
return line.substring(0, commaOccurence);
}
/**
* Gets the text part of a line that is stored in the
* properties file.
*
* @param element The element the text is got from.
* @return String representation of the text.
*/
private static String extractText(String line) {
final int commaOccurence = getFirstCommaOccurrence(line);
return line.substring(commaOccurence + 1, line.length());
}
/**
* Gets the first occurrence of a comma in any given line of a text file.
* @param element
* @return
*/
private static int getFirstCommaOccurrence(String line) {
return line.indexOf(",");
}