cron 表达式转换

import static com.cronutils.model.field.expression.FieldExpressionFactory.always;
import static com.cronutils.model.field.expression.FieldExpressionFactory.every;
import static com.cronutils.model.field.expression.FieldExpressionFactory.on;
import static com.cronutils.model.field.expression.FieldExpressionFactory.questionMark;

import com.cronutils.builder.CronBuilder;
import com.cronutils.model.Cron;
import com.cronutils.model.CronType;
import com.cronutils.model.definition.CronDefinitionBuilder;

public class Test {
	
	public static void main(String[] args) {
		Cron cron = CronBuilder.cron(CronDefinitionBuilder.instanceDefinitionFor(CronType.QUARTZ))
			    .withYear(always())
			    .withDoW(questionMark())
			    .withMonth(always())
			    .withDoM(always())
			    .withHour(always())
			    .withMinute(every(5))
			    .withSecond(on(0))
			    .instance();
			// Obtain the string expression
			String cronAsString = cron.asString(); // 0 */5 * * * ? * 每5分钟一次
			
			
			System.out.println(cronAsString);
	}

}

https://github.com/jmrozanec/cron-utils

https://www.cnblogs.com/be-come/p/6165293.html

http://cron.qqe2.com/