Java Scheduling API - 特定的时间间隔

Question

我是Java的新手，我正在尝试生成一个将在特定时间运行的任务。有三种类型的时间表：a）在一年中执行每个给定的天数，b）在一个月中执行每个给定的时间量（在特定月份中执行1到10次），c）执行每个给定的一周月（一个星期从1到5个月）。

a到c的字母是时间表的选择。

我尝试了几件事但到目前为止没有任何工作。我使用了TimerTask，Calendar和Timer API。我最近的努力如下：

public class Runner {
public static void runTask(int year, int month, int day, int hour, int minute, int second, String choice) {

    Calendar startTime = Calendar.getInstance();
    startTime.set(Calendar.YEAR, year );
    startTime.set(Calendar.MONTH,month);
    startTime.set(Calendar.DAY_OF_MONTH,day);
    startTime.set(Calendar.HOUR_OF_DAY, hour);
    startTime.set(Calendar.MINUTE, minute);
    startTime.set(Calendar.SECOND, second);
    startTime.set(Calendar.MILLISECOND, 0);

    Calendar bStartTime = Calendar.getInstance();
    bStartTime.set(Calendar.YEAR,year);
    bStartTime.set(Calendar.MONTH,month-1);
    bStartTime.set(Calendar.DAY_OF_MONTH,1);
    bStartTime.set(Calendar.HOUR_OF_DAY,12);
    bStartTime.set(Calendar.MINUTE, 0);
    bStartTime.set(Calendar.SECOND, 0);
    bStartTime.set(Calendar.MILLISECOND, 0);
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy MMM dd");
    long timeToEnd = 0;

    if (choice.equals("a")) {
        Timer time = new Timer();

        time.schedule(new SpecificTask(), startTime.getTime(), TimeUnit.DAYS.toMillis(1));

    }
    else if(choice.equals("b")){
        System.out.println("How many times the task should be done in "+year+"."+month);
        int counter = 0;
        Scanner sc = new Scanner(System.in);
        counter = sc.nextInt();

        Timer time = new Timer();
        time.schedule(new SpecificTask(), bStartTime.getTime(), TimeUnit.DAYS.toMillis(30/counter));
        System.out.println("Date of start : " + sdf.format(bStartTime.getTime()));

    }
    else if(choice.equals("c")){
        Timer time = new Timer();
        time.schedule(new SpecificTask(), startTime.getTime(), TimeUnit.SECONDS.toMillis(2));
    }
    else{
        System.out.println("An error has been occured");

    }

}
public static void main(String[] args) {
    int year,month,day,hour,minute,second;
    String choiceOfSchedule;
    System.out.println("Welcome in The Ultimate Task Scheduler");
    System.out.print("Select a type of schedule: ");
    Scanner sc = new Scanner(System.in);
    choiceOfSchedule = sc.nextLine();
    System.out.println("Now set the task's starting time: ... ");
    System.out.println(" Set year: ");
    year = sc.nextInt();
    System.out.print(" Set month: ");
    month =sc.nextInt();
    System.out.print(" Set day: ");
    day = sc.nextInt();
    System.out.print(" Set hour: ");
    hour = sc.nextInt();
    System.out.print( " Set minutes: ");
    minute = sc.nextInt();
    System.out.print(" Set seconds: ");
    second = sc.nextInt();
    runTask(year,month,day,hour,minute,second,choiceOfSchedule);

Answer 1

Write one scheduling class per scenario

对我来说，编写一种处理这种不同场景的方法似乎毫无意义。我会为每个场景编写一个类。在设置调度时，每种任务都会知道要使用哪个调度程序类。

public class DaysPerYearScheduler { … }

public class TimesPerMonthScheduler { … }

public class OrdinalWeekPerMonthScheduler { … }

作为类比，您试图在BigDecimal上执行相当于单个方法的加法和减法，乘法和除法以及求平均值。这不是很尴尬吗？

学习使用取代Timer类的Executor框架。 Stack Overflow上已经多次介绍过这个问题。

切勿使用Calendar。几年前java.time类取代了这个可怕的类。避免在java.time.*包之外的任何日期时间类。