如何在Java中附加文件

Question

How do I append the highscore into highscore.txt file at the correct position in descending order? The method uses readHighScore(int score) method created previously to find the line number where the record should be inserted. This is what I got so far:

public static void recordHighScore(String name, int score){
            File file = new File("Test/highscore.txt");
            FileWriter fwriter = new FileWriter(file, true);
            try{
                String userName = name+","+score;
                fwriter.add(readHighScore(score), userName);

            }catch(IOException io){
                System.out.println("Missing File!");

            }

            /*Writes the high score into highscore.txt file, at the correct position (in descending order). This
            method uses readHighScore( ) method to find the line number where the record should be
            inserted.*/
        }

Answer 1

It's very easy if you want to append data at the end, and almost impossible if you want append data at the middle. Much easy read all file in memory, change it and save all file again, overwriting old informaton.

For example:

// read file to arraylist
Scanner s = new Scanner(new File("filepath"));
List<Score> list = new ArrayList<Score>();
while (s.hasNext()){
    String[] a = s.next().split(","); 
    list.add(new Score(a[0], a[1]); ); // Score is class with name and score fields
}
s.close();

// working with List<Score>
// add new score to List<Score>
// save List<Score> to file like in your code