一般在写定时任务的时候都是后台定义好的定时时间,但根据不同的项目需求需要客户去配置某个时间段的定时,把操作权给用户 所以就需要后端人员通过前端传值的方式来实现定时任务配置;

先看一下项目的原型图

cron java 在线 java生成cron_官网


类似于core表达式官网的效果,我查询了一下core表达式官网的配置发现他们通过JS进行拼接的方式;

相对于我们来说更倾向于后台去拼接这样的话能保证表达式正确性,前端也比较费时费力;以下就是后端的解决方案:

TaskScheduleModel.java

public class TaskScheduleModel {
    /**
     * 所选作业类型:
     * 0  ->每次
     * 1  -> 每天
     * 2  -> 每月
     * 3  -> 每周
     * 4  ->间隔(每隔2个小时,每隔30分钟)
     */
    Integer jobType;

    /**一周的哪几天*/
    Integer[] dayOfWeeks;

    /**一个月的哪几天*/
    Integer[] dayOfMonths;

    /**秒  */
    Integer second;

    /**分  */
    Integer minute;

    /**时  */
    Integer hour;

    Integer beApart;

    public Integer getBeApart() {
        return beApart;
    }

    public void setBeApart(Integer beApart) {
        this.beApart = beApart;
    }

    public Integer getJobType() {
        return jobType;
    }

    public void setJobType(Integer jobType) {
        this.jobType = jobType;
    }

    public Integer[] getDayOfWeeks() {
        return dayOfWeeks;
    }

    public void setDayOfWeeks(Integer[] dayOfWeeks) {
        this.dayOfWeeks = dayOfWeeks;
    }

    public Integer[] getDayOfMonths() {
        return dayOfMonths;
    }

    public void setDayOfMonths(Integer[] dayOfMonths) {
        this.dayOfMonths = dayOfMonths;
    }

    public Integer getSecond() {
        return second;
    }

    public void setSecond(Integer second) {
        this.second = second;
    }

    public Integer getMinute() {
        return minute;
    }

    public void setMinute(Integer minute) {
        this.minute = minute;
    }

    public Integer getHour() {
        return hour;
    }

    public void setHour(Integer hour) {
        this.hour = hour;
    }
}

公共方法:

/**
     * @ClassName: CronUtil
     * @Description: Cron表达式工具类
     * 目前支持三种常用的cron表达式
     * 1.每天的某个时间点执行 例:12 12 12 * * ?表示每天12时12分12秒执行
     * 2.每周的哪几天执行         例:12 12 12 ? * 1,2,3表示每周的周1周2周3 ,12时12分12秒执行
     * 3.每月的哪几天执行         例:12 12 12 1,21,13 * ?表示每月的1号21号13号 12时12分12秒执行
     * @author
     * @date
     *
     */

    /**
     *
     *方法摘要:构建Cron表达式
     *@param  taskScheduleModel
     *@return String
     */
    public static String createCronExpression(TaskScheduleModel taskScheduleModel){
        StringBuffer cronExp = new StringBuffer("");

        if(null == taskScheduleModel.getJobType()) {
            System.out.println("执行周期未配置" );//执行周期未配置
        }

        if (null != taskScheduleModel.getSecond()
                && null != taskScheduleModel.getMinute()
                && null != taskScheduleModel.getHour()) {
            //秒
            cronExp.append(taskScheduleModel.getSecond()).append(" ");
            //分
            cronExp.append(taskScheduleModel.getMinute()).append(" ");
            //小时
            cronExp.append(taskScheduleModel.getHour()).append(" ");
            //每天
            if(taskScheduleModel.getJobType().intValue() == 1){
                //12 12 12 1/2 * ? *
                //12 12 12 * * ?
                if(taskScheduleModel.getBeApart()!=null){
                    cronExp.append("1");//日
                    cronExp.append("/");
                    cronExp.append(taskScheduleModel.getBeApart()+1);//月
                    cronExp.append(" ");
                    cronExp.append("* ");
                    cronExp.append("? ");//周
                    cronExp.append("*");
                }else {
                    cronExp.append("* ");//日
                    cronExp.append("* ");//月
                    cronExp.append("?");//周
                }
            }

            //按每周
            else if(taskScheduleModel.getJobType().intValue() == 3){
                //一个月中第几天
                cronExp.append("? ");
                //月份
                cronExp.append("* ");
                //周
                Integer[] weeks = taskScheduleModel.getDayOfWeeks();
                for(int i = 0; i < weeks.length; i++){
                    if(i == 0){
                        cronExp.append(weeks[i]);
                    } else{
                        cronExp.append(",").append(weeks[i]);
                    }
                }

            }

            //按每月
            else if(taskScheduleModel.getJobType().intValue() == 2){
                //一个月中的哪几天
                Integer[] days = taskScheduleModel.getDayOfMonths();
                for(int i = 0; i < days.length; i++){
                    if(i == 0){
                        if(days[i]==32){
                            //本月最后一天
                            String endMouthCron="0 0 0 L * ?";
                            return endMouthCron;
                        }else {
                            cronExp.append(days[i]);
                        }
                    } else{
                        cronExp.append(",").append(days[i]);
                    }
                }
                //月份
                cronExp.append(" * ");
                //周
                cronExp.append("?");
            }
            else if(taskScheduleModel.getJobType().intValue() == 0){
                    cronExp.append("* ");//日
                    cronExp.append("* ");//月
                    cronExp.append("?");//周
            }
        }
        else {
            System.out.println("时或分或秒参数未配置" );//时或分或秒参数未配置
        }
        return cronExp.toString();
    }

    /**
     *
     *方法摘要:生成计划的详细描述
     *@param  taskScheduleModel
     *@return String
     */
    public static String createDescription(TaskScheduleModel taskScheduleModel){
        StringBuffer description = new StringBuffer("");
        //计划执行开始时间
//      Date startTime = taskScheduleModel.getScheduleStartTime();

        if (null != taskScheduleModel.getSecond()
                && null != taskScheduleModel.getMinute()
                && null != taskScheduleModel.getHour()) {
            //按每天
            if(taskScheduleModel.getJobType().intValue() == 1){
                description.append("每天");
                description.append(taskScheduleModel.getHour()).append("时");
                description.append(taskScheduleModel.getMinute()).append("分");
                description.append(taskScheduleModel.getSecond()).append("秒");
                description.append("执行");
            }

            //按每周
            else if(taskScheduleModel.getJobType().intValue() == 3){
                if(taskScheduleModel.getDayOfWeeks() != null && taskScheduleModel.getDayOfWeeks().length > 0) {
                    String days = "";
                    for(int i : taskScheduleModel.getDayOfWeeks()) {
                        days += "周" + i;
                    }
                    description.append("每周的").append(days).append(" ");
                }
                if (null != taskScheduleModel.getSecond()
                        && null != taskScheduleModel.getMinute()
                        && null != taskScheduleModel.getHour()) {
                    description.append(",");
                    description.append(taskScheduleModel.getHour()).append("时");
                    description.append(taskScheduleModel.getMinute()).append("分");
                    description.append(taskScheduleModel.getSecond()).append("秒");
                }
                description.append("执行");
            }

            //按每月
            else if(taskScheduleModel.getJobType().intValue() == 2){
                //选择月份
                if(taskScheduleModel.getDayOfMonths() != null && taskScheduleModel.getDayOfMonths().length > 0) {
                    String days = "";
                    for(int i : taskScheduleModel.getDayOfMonths()) {
                        days += i + "号";
                    }
                    description.append("每月的").append(days).append(" ");
                }
                description.append(taskScheduleModel.getHour()).append("时");
                description.append(taskScheduleModel.getMinute()).append("分");
                description.append(taskScheduleModel.getSecond()).append("秒");
                description.append("执行");
            }

        }
        return description.toString();
    }


    /**
     * @description: 构建Cron表达式
     * @param rate cycle
     * @return  String
     * @author panlupeng
     * @date 2021/9/27 15:55 
     */
     public static String createLoopCronExpression(int rate, int cycle) {
                 String cron = "";
                 switch (rate) {
                     case 0:// 每cycle秒执行一次
                             cron = "0/" + cycle + " * * * * ?";
                             break;
                     case 1:// 每cycle分钟执行一次
                             cron = "0 0/" + cycle + " * * * ?";
                             break;
                     case 2:// 每cycle小时执行一次
                             cron = "0 0 0/" + cycle + " * * ?";
                             break;
                     case 3:// 每cycle天的0点执行一次
                             cron = "0 0 0 1/" + cycle + " * ?";
                             break;
                     case 4:// 每cycle月的1号0点执行一次
                             cron = "0 0 0 1 1/" + cycle + " ? ";
                             break;
                     case 5://  每天cycle点执行一次
                             cron = "0 0 " + cycle+ "  * * ?";
                             break;
                     default:// 默认每cycle秒执行一次
                             cron = "0/1 * * * * ?";
                             break;
                     }
                 return cron;
             }

  public static void main(String[] args) {
        //执行时间:每天的12时12分12秒 start
        TaskScheduleModel taskScheduleModel = new TaskScheduleModel();
        taskScheduleModel.setJobType(1);//按每天
        Integer hour = 12; //时
        Integer minute = 12; //分
        Integer second = 12; //秒
        taskScheduleModel.setHour(hour);
        taskScheduleModel.setMinute(minute);
        taskScheduleModel.setSecond(second);
        //每隔几天执行
        taskScheduleModel.setBeApart(1);
        String cropExp = createCronExpression(taskScheduleModel);
        System.out.println(cropExp + ":" + createDescription(taskScheduleModel));
        //执行时间:每天的12时12分12秒 end

        taskScheduleModel.setJobType(3);//每周的哪几天执行
        Integer[] dayOfWeeks = new Integer[3];
        dayOfWeeks[0] = 1;
        dayOfWeeks[1] = 2;
        dayOfWeeks[2] = 3;
        taskScheduleModel.setDayOfWeeks(dayOfWeeks);
        cropExp = createCronExpression(taskScheduleModel);
        System.out.println(cropExp + ":" + createDescription(taskScheduleModel));

        taskScheduleModel.setJobType(2);//每月的哪几天执行
        Integer[] dayOfMonths = new Integer[3];
        dayOfMonths[0] = 1;
        dayOfMonths[1] = 21;
        dayOfMonths[2] = 13;
        taskScheduleModel.setDayOfMonths(dayOfMonths);
        cropExp = createCronExpression(taskScheduleModel);
        System.out.println(cropExp + ":" + createDescription(taskScheduleModel));

        taskScheduleModel.setJobType(0);//每天的几点几分几秒开始
        cropExp = createCronExpression(taskScheduleModel);
        System.out.println(cropExp);


    }

测试一下:

cron java 在线 java生成cron_定时任务_02