Java定时调度工具包devtools-cron4j使用介绍

devtools-cron4j是一款小巧实用的Java调度工具包，来自于devtools系列，它提供了：

1. 支持以API方式来定义cron表达式
2. 内置多种调度器实现(Timer, Executor等)
3. 支持中断策略(Cancellable)

安装:

---

        <dependency>
            <groupId>com.github.paganini2008</groupId>
            <artifactId>devtools-cron4j</artifactId>
            <version>2.0.3</version>
        </dependency>

兼容性

---

• Jdk1.8+

  如何生成cron表达式？

  ---

  参考例子：

       // */5 * * * * ?
    public static CronExpression getCron1() {
        return CronExpressionBuilder.everySecond(5);
    }
  
    // 0 */2 * * * ?
    public static CronExpression getCron2() {
        return CronExpressionBuilder.everyMinute(2);
    }
  
    // 0 26,29,33 * * * ?
    public static CronExpression getCron3() {
        return CronExpressionBuilder.everyHour().minute(26).andMinute(29).andMinute(33);
    }
  
    // 0 * 14 * * ?
    public static CronExpression getCron4() {
        return CronExpressionBuilder.everyDay().hour(14).everyMinute();
    }
  
    // 0 0-10 15 * * ?
    public static CronExpression getCron5() {
        return CronExpressionBuilder.everyDay().hour(15).minute(0).toMinute(10);
    }
  
    // 0 0 23 * * ?
    public static CronExpression getCron6() {
        return CronExpressionBuilder.everyDay().at(23, 0);
    }
  
    // 0 15 12 * * ?
    public static CronExpression getCron7() {
        return CronExpressionBuilder.everyDay().hour(12).minute(15);
    }
  
    // 0 0 0,13,18,21 * * ?
    public static CronExpression getCron8() {
        return CronExpressionBuilder.hour(13).andHour(18).andHour(21);
    }
  
    // 0 15 10 ? * 6L
    public static CronExpression getCron9() {
        return CronExpressionBuilder.everyMonth().lastWeek().Fri().at(10, 15);
    }
  
    // 0 15 10 ? * MON-FRI
    public static CronExpression getCron10() {
        return CronExpressionBuilder.everyWeek().Mon().toFri().at(10, 15, 0);
    }
  
    // 0 0/5 12,18 * * ?
    public static CronExpression getCron11() {
        return CronExpressionBuilder.hour(12).andHour(18).everyMinute(5);
    }
  
    // 0 30 23 L * ?
    public static CronExpression getCron12() {
        return CronExpressionBuilder.everyMonth().lastDay().at(23, 30);
    }
  
    // 0 10,20,30 12 ? 7-11 6L 2021-2025
    public static CronExpression getCron13() {
        return CronExpressionBuilder.year(2021).toYear(2025).Aug().toDec().lastWeek().Fri().hour(12).minute(10).andMinute(20).andMinute(30);
    }
  
    // 0 10 23 ? * 6#3
    public static CronExpression getCron14() {
        return CronExpressionBuilder.everyMonth().week(3).Fri().at(23, 10);
    }
  
    // 0 15-50/2 0-6 10-28 * ?
    public static CronExpression getCron15() {
        return CronExpressionBuilder.everyMonth().day(10).toDay(28).hour(0).toHour(6).minute(15).toMinute(50, 2);
    }

如何解析cron表达式？

---

        System.out.println(CRON.parse("*/5 * * * * ?"));
        System.out.println(CRON.parse("0 */2 * * * ?"));
        System.out.println(CRON.parse("0 15 10 LW * ?"));
        System.out.println(CRON.parse("0 0 12 10W * ?"));
        System.out.println(CRON.parse("0 15 10 ? * MON-FRI"));
        System.out.println(CRON.parse("0 26,29,33 * * * ?"));
        System.out.println(CRON.parse("0 15-50/2 0-6 10-28 * ?"));
        System.out.println(CRON.parse("0 10 23 ? * 6#3"));
        System.out.println(CRON.parse("0 10,20,30 12 ? 7-11 6L 2021-2025"));

如何测试cron表达式？

---

        CRON.parse("0 30 23 L * ?").forEach(date -> {
            System.out.println(DateUtils.format(date));
        }, 20);

        System.out.println("-----------------------------------------");

        CRON.parse("0 0 12 10-15 * ?").forEach(date -> {
            System.out.println(DateUtils.format(date));
        }, 20);

如何执行调度程序？

---

        CronExpression expression = CronExpressionBuilder.everySecond(5);
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.schedule(new Task() {

            @Override
            public boolean execute() {
                System.out.println("Task is running at: " + new Date());
                return true;
            }

            @Override
            public Cancellable cancellable() {
                return Cancellables.cancelIfRuns(-1);
            }

            @Override
            public void onCancellation(Throwable e) {
                System.out.println("Cancelled.");
            }

        }, expression);

        System.in.read();
        executor.close();

源码地址：https://github.com/paganini20...