Question

我正在尝试创建一种方法，该方法将接收用户输入的任务和截止日期，并按截止日期对其进行排序。我有为任务编写的代码，它编译，但当我尝试排序它似乎删除所有内容。我在写原始文件吗？如何更正此内容以将其添加到同一文件而不删除？

public class DueDate implements Comparable<DueDate>{

    public String addedTask = "";
    public String dueDate = "";


    public DueDate(String addedTask, String dueDate){

        this.addedTask = addedTask;
        this.dueDate = dueDate;
    }

    public String toString(){
        return addedTask+"\t"+dueDate+"\t";
    }

    @Override
    public int compareTo(DueDate o) {
        return this.dueDate.compareTo(o.dueDate);
    }
}

public class Main {

    public static String fileName = "/Users/eri/Desktop/tasklistjava/src/javatask.txt";

    public static void main(String[] args) throws IOException {

        int menuItem = -1;
        while(menuItem != 0){
            menuItem = menu();
            switch (menuItem){
                case 1:
                    showTaskList();
                    break;
                case 2:
                    addTask();
                    break;
                case 3:
                    sortList();
                case 4:
                    deleteTasks();
                    break;
                case 0:
                    break;
                default:
                    System.out.println("Invalid Input");

            }
        }
    }

static void sortList() throws IOException {
        System.out.println("\nSorted List\n");
        try {
            BufferedReader br = new BufferedReader(new FileReader(fileName));
            BufferedWriter bw = new BufferedWriter(new FileWriter(fileName));
            ArrayList<DueDate> tasks = new ArrayList<DueDate>();
            String line = "";
            while((line = br.readLine()) != null) {
                String[] values = line.split("-");

                if(values.length == 2) {
                    String addedTask = values[0];
                    String dueDate = values[1];

                    DueDate d = new DueDate(addedTask, dueDate);

                    tasks.add(d);
                }
            }

            Collections.sort(tasks);

            for(int i = 0; i < tasks.size(); i++){
                DueDate date = tasks.get(i);
                String lineText = date.toString();
                bw.write(lineText);
                bw.newLine();
            }

            br.close();
            bw.close();

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

Answer 1

通常，当您想要对文件中的记录进行排序时，您首先要取出内容并将其存储在arraylist中，然后在arraylist中对其进行排序。然后删除旧文件并将已排序的数据写入新文件。

将日期排序为字符串Java

1 个答案: