java - 从 csv 读取，根据第一部分删除行

Question

在我的应用程序中，我在 JList 中显示 CSV 每一行的第一部分，当选择它并按下按钮(删除)时，我希望它根据第一个条目从文件中删除该行。我正在尝试一种方法，您有一个临时文件，然后写入它，然后在最后重命名它，但由于某种原因，这不起作用。有什么想法吗？

private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:
    // Delete service
    String selected = (String) jList1.getSelectedValue();
    File passwords = new File("/users/aak7133/desktop/passwords.txt");
    File temp = new File("/users/aak7133/desktop/temp.txt");

    try {
        BufferedReader reader = new BufferedReader(new FileReader(passwords));
        BufferedWriter writer = new BufferedWriter(new FileWriter(temp));
        String line;
        System.out.println(selected);
        while ((line = reader.readLine()) != null) {
            // trim newline when comparing with lineToRemove
            //String trimmedLine = line.trim();

            if (line.contains(selected)) {
                continue;
            }
            writer.write(line);
        }
        boolean successful = temp.renameTo(passwords);

    } catch (Exception e) {

    }
    updateList();
    clearFields();

} 

Answer 1

这个问题实际上是由开放的读者和作者造成的。这应该有效:

private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {
    String selected = (String) jList1.getSelectedValue();
    BufferedReader reader = null;
    BufferedWriter writer = null;
    try {
        File passwords = new File("/users/aak7133/desktop/passwords.txt");
        File temp = File.createTempFile("temp", ".txt", new File("/users/aak7133/desktop/"));
        reader = new BufferedReader(new FileReader(passwords));
        writer = new BufferedWriter(new FileWriter(temp));
        String line;
        System.out.println(selected);
        while ((line = reader.readLine()) != null) {
            // trim newline when comparing with lineToRemove
            // String trimmedLine = line.trim();

            if (line.contains(selected)) {
                continue;
            }
            writer.write(line + "\n");
        }
        if (passwords.canWrite()) {
            try {
                reader.close();
                reader = null;
            } catch (IOException ignore) {}

            try {
                writer.close();
                writer = null;
            } catch (IOException ignore) {}

            String path = passwords.getAbsolutePath();
            passwords.delete();
            boolean successful = temp.renameTo(new File(path));
            System.out.println(successful);

        }

    } catch (Exception e) {

    } finally {
        if (reader != null) {
            try {
                reader.close();
            } catch (IOException ignore) {}
        }
        if (writer != null) {
            try {
                writer.close();
            } catch (IOException ignore) {}
        }
    }
     updateList();
     clearFields();
}