public void importData() { try { List<String> courses = Files.readAllLines(Paths.get("data/courses.txt"), StandardCharsets.UTF_8); List<String> scores = Files.readAllLines(Paths.get("data/scores.txt"), StandardCharsets.UTF_8); List<String> ids = Files.readAllLines(Paths.get("data/credits.txt"), StandardCharsets.UTF_8); List<String> semesters = Files.readAllLines(Paths.get("data/semesters.txt"), StandardCharsets.UTF_8); List<String> courseTypes = Files.readAllLines(Paths.get("data/types.txt"), StandardCharsets.UTF_8); this.courses.clear(); for (int i = 0; i < courses.size(); i++) { String course = courses.get(i); String id = ids.get(i); String score = scores.get(i); String semester = semesters.get(i); String courseType = courseTypes.get(i); addData(course,id,score,semester,courseType); Course student = new Course(course, score,id, semester, courseType); this.courses.add(student); //updateDisplay(); } //updateDisplay(); JOptionPane.showMessageDialog(null, "Data has been imported"); } catch (IOException e) { JOptionPane.showMessageDialog(null, "An error occurred importing data"); } }优化这个代码

可以优化的几个方面：

1. 将重复的文件读取操作提取成一个方法，避免代码重复。

2. 使用 try-with-resources 语句来自动关闭资源，避免忘记关闭资源导致的资源泄漏。

3. 在 for 循环中，可以使用更简洁的 foreach 循环。

4. 在 for 循环中，不必要地创建了一个 Course 对象，可以直接调用 addData 方法添加数据。

优化后的代码如下：

public void importData() {
    List<String> files = Arrays.asList("courses.txt", "scores.txt", "credits.txt", "semesters.txt", "types.txt");
    List<List<String>> fileContents = new ArrayList<>();
    for (String file : files) {
        try (Stream<String> stream = Files.lines(Paths.get("data/" + file), StandardCharsets.UTF_8)) {
            fileContents.add(stream.collect(Collectors.toList()));
        } catch (IOException e) {
            JOptionPane.showMessageDialog(null, "An error occurred importing data");
            return;
        }
    }
    this.courses.clear();
    for (int i = 0; i < fileContents.get(0).size(); i++) {
        String course = fileContents.get(0).get(i);
        String id = fileContents.get(2).get(i);
        String score = fileContents.get(1).get(i);
        String semester = fileContents.get(3).get(i);
        String courseType = fileContents.get(4).get(i);
        addData(course, id, score, semester, courseType);
        this.courses.add(new Course(course, score, id, semester, courseType));
    }
    JOptionPane.showMessageDialog(null, "Data has been imported");
}