Question

我在java中创建任务列表，并希望能够按用户输入的截止日期对数据进行排序。以下是我到目前为止的情况。对于switch语句的case 3，我想在情况2中按变量dueDate排序：我怎么能访问它？我可以使用collection.sort作为日期吗？

import java.io.*;
import java.util.Scanner;

public class Main {

    public static String fileName = "/Users/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();
                    break;
                case 0:
                    break;
                default:
                    System.out.println("Invalid Input");

            }
        }
    }
    static int menu(){
        int choice;
        Scanner sc = new Scanner(System.in);
        System.out.println("\n Task List Menu \n");
        System.out.println("0: Exit Menu");
        System.out.println("1: Show Tasks in List");
        System.out.println("2: Add Task to List");
        System.out.println("3: Sort Tasks by Due Date");
        System.out.println();
        System.out.println("Enter a choice: ");
            choice = sc.nextInt();
            return choice;
    }

    static void showTaskList(){
        System.out.println("\nTask List\n");
        try {
            Scanner inFile = new Scanner(new FileReader(fileName));
            String line;
            int number = 1;
            while(inFile.hasNextLine()){
                line = inFile.nextLine();
                System.out.println(number + ". " + line);
                ++number;
            }
            System.out.println();
            inFile.close();
        } catch (FileNotFoundException ioe) {
            System.out.println(ioe);
        }
    }

    static void addTask(){
        System.out.println("\nAdd Task\n");
        try {
            Scanner input = new Scanner(System.in);
            PrintWriter outFile = new PrintWriter(new FileWriter(fileName, true));
            System.out.println("Enter a Task: ");
            String addedTask = input.nextLine();
            System.out.println("Set Due Date for this Task(yyyy-mm-dd): ");
            String dueDate = input.nextLine();
            outFile.println(addedTask + " " + dueDate);
            outFile.close();
        } catch (IOException ioe) {
            System.out.println(ioe);
        }
    }
    static void sortList(){
        System.out.println("\nSorted List\n");

  }

}

Answer 1

是的，您可以使用Collections.sort（）。

但是，您需要实现Comparable或Comparator来添加您自己的逻辑以对其进行排序。

尝试搜索可比较和比较器，你应该看看如何做。

按用户输入的日期排序java任务

1 个答案: