是否有用于创建Cron表达式的Java代码？ [英] Is there any Java code for creating Cron Expression?

问题描述

我需要Java代码才能根据用户输入创建cron表达式。
用户输入的是时间，频率和执行次数。

I need a Java code to create a cron expression based on user inputs. User inputs are Time, frequency and number of executions.

推荐答案

只需在创建它的注释中添加

Just adding on from the comment that says create it yourself.

这里是一个示例：提示用户输入值并将它们传递给以下方法，Javadoc解释了允许使用哪个值（取自 http://en.wikipedia.org/wiki/Cron#Format ）。

Here is an example: Prompt the user for the values and pass them into the following method, the Javadoc explains what is allowed in which value (taken from http://en.wikipedia.org/wiki/Cron#Format).

这是未经测试的，不会验证任何输入字符串，但我确定您可以做到。

This is untested and doesn't validate any of the input strings, but I'm sure you can do that.

/**
 * Generate a CRON expression is a string comprising 6 or 7 fields separated by white space.
 *
 * @param seconds    mandatory = yes. allowed values = {@code  0-59    * / , -}
 * @param minutes    mandatory = yes. allowed values = {@code  0-59    * / , -}
 * @param hours      mandatory = yes. allowed values = {@code 0-23   * / , -}
 * @param dayOfMonth mandatory = yes. allowed values = {@code 1-31  * / , - ? L W}
 * @param month      mandatory = yes. allowed values = {@code 1-12 or JAN-DEC    * / , -}
 * @param dayOfWeek  mandatory = yes. allowed values = {@code 0-6 or SUN-SAT * / , - ? L #}
 * @param year       mandatory = no. allowed values = {@code 1970–2099    * / , -}
 * @return a CRON Formatted String.
 */
private static String generateCronExpression(final String seconds, final String minutes, final String hours,
                                             final String dayOfMonth,
                                             final String month, final String dayOfWeek, final String year)
{
  return String.format("%1$s %2$s %3$s %4$s %5$s %6$s %7$s", seconds, minutes, hours, dayOfMonth, month, dayOfWeek, year);
}

Cron格式信息取自此处： http://en.wikipedia.org/wiki/Cron#Format

Cron Format Information taken from here: http://en.wikipedia.org/wiki/Cron#Format

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