Sorting a Text File in JavaFX

问题

So I can successfully create a score board, and then dynamically update this scoreboard with the 3 variables. However, I now need to sort the scoreboard based on the score (so the variable score here) and put the top 10 scores on the TextArea. How do I do this using a Collection Sort?

The method which writes the 3 variables into the Text File

public void newScore() {
    try (BufferedWriter bw = new BufferedWriter(new FileWriter("xxxxx/gameScores.txt", true))) {

        int score = player.getPoints();
        String names = name.getText();
        String levelSelected = choose.getLevel();

        bw.write(names + "          " + score + "          " + levelSelected);
        bw.write("\n");

    } catch (IOException e) {
        e.printStackTrace();
    }

    textArea.clear();
    scoreBoard();
}

My method which reads the text file and dynamically appends to the TextArea (AKA, the score board)

public void scoreBoard() {

    File scoreFile = new File("xxxxx/gameScores.txt");

    try (Scanner scoresList = new Scanner(scoreFile)) {
        while (scoresList.hasNext()) {
            textArea.appendText(scoresList.nextLine());
            textArea.appendText("\n");
        }
    } catch (FileNotFoundException ex) {
        System.out.println("ERROR");
    }
}

回答1:

I think you need to create an object to hold what represents one instance of scoreboard data. Name:Score:Level. When you read the data from the file read it an as a List of ScoreBoardScore. List<ScoreBoardScore>. One way to sort the List of ScoreBoardScore is to use Collections.sort. Example code below. Comments in the code.

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
 *
 * @author Sedrick
 */
public class Main
{
    public static void main(String[] args)
    {
        List<ScoreBoardScore> scoreBoardScores = getScoreFromFile();//get List of ScoreBoardScore from file.
        scoreBoardScores.forEach(System.out::println);//Print scores before sort.

        //sort data
        //This sorts in decending order. To get acending order change if(o1.getScore() < o2.getScore()) to if(o1.getScore() > o2.getScore())
        Collections.sort(scoreBoardScores, Comparator.comparingInt(ScoreBoardScore::getScore).reversed());

        System.out.println("\nAfter Sort:");
        scoreBoardScores.forEach(System.out::println);//Print scores after sort.
    }

    static List<ScoreBoardScore> getScoreFromFile()
    {
        //simulate reading a file and returning a List of Scores
        String fakeFileData = "John Doe     91     8\n"
                            + "jane Doe     100     9\n"
                            + "Kim Johnson     88     7\n"
                            + "Kim Johnson     95     8";

        List<String> lines = new ArrayList(Arrays.asList(fakeFileData.split("\n")));//These simulate the lines of a file.

        List<ScoreBoardScore> scoreBoardScores = new ArrayList();
        for(int i = 0; i < lines.size(); i++)//loop through the lines and split the data based on more than two spaces. I didn't use one space or more because the name has one space.
        {
            String[] splitData = lines.get(i).split("\\s{2,}");//Split on two or more spaces
            scoreBoardScores.add(new ScoreBoardScore(splitData[0], Integer.parseInt(splitData[1]), splitData[2]));//Use the data to create ScoreBoardScores.
        }

        return scoreBoardScores;
    }
}

Output:

--- exec-maven-plugin:1.5.0:exec (default-cli) @ JavaTestingGround ---
ScoreBoardScore{score=91, name=John Doe, level=8}
ScoreBoardScore{score=100, name=jane Doe, level=9}
ScoreBoardScore{score=88, name=Kim Johnson, level=7}
ScoreBoardScore{score=95, name=Kim Johnson, level=8}

After Sort:
ScoreBoardScore{score=100, name=jane Doe, level=9}
ScoreBoardScore{score=95, name=Kim Johnson, level=8}
ScoreBoardScore{score=91, name=John Doe, level=8}
ScoreBoardScore{score=88, name=Kim Johnson, level=7}
------------------------------------------------------------------------
BUILD SUCCESS
------------------------------------------------------------------------
Total time: 1.673 s
Finished at: 2019-12-11T14:25:58-06:00
Final Memory: 12M/40M
------------------------------------------------------------------------

来源：https://stackoverflow.com/questions/59292544/sorting-a-text-file-in-javafx

标签

java

sorting

javafx