Cron工具获取上次执行时间和下次执行时间

Posted 2021-10-02 抓手

spring的CronSequenceGenerator工具不支持7位cron表达式，也不支持含非数字"L"的表达式：

IllegalArgumentException: Cron expression must consist of 6 fields (found 7 in "34 20 18 L 1/3 ? *")

NumberFormatException: For input string: "L"

后来在GitHub上找到一个工具：GitHub - jmrozanec/cron-utils: Cron utils for parsing, validations and human readable descriptions as well as date/time interoperability.

<dependency>
    <groupId>com.cronutils</groupId>
    <artifactId>cron-utils</artifactId>
    <version>9.1.5</version>
</dependency>

然后自定义封装了一下：

import com.cronutils.model.Cron;
import com.cronutils.model.definition.CronDefinition;
import com.cronutils.model.definition.CronDefinitionBuilder;
import com.cronutils.model.time.ExecutionTime;
import com.cronutils.parser.CronParser;

import java.time.LocalDateTime;
import java.time.ZonedDateTime;
import java.util.Optional;

import static com.cronutils.model.CronType.QUARTZ;

/**
 * @author 向振华
 * @date 2021/09/13 09:33
 */
public class CronUtils {

    private static final CronDefinition CRON_DEFINITION = CronDefinitionBuilder.instanceDefinitionFor(QUARTZ);

    public static LocalDateTime lastExecution(String expression) {
        CronParser parser = new CronParser(CRON_DEFINITION);
        Cron quartzCron = parser.parse(expression);
        ZonedDateTime now = ZonedDateTime.now();
        ExecutionTime executionTime = ExecutionTime.forCron(quartzCron);
        Optional<ZonedDateTime> zonedDateTimeOptional = executionTime.lastExecution(now);
        if (zonedDateTimeOptional.isPresent()) {
            ZonedDateTime zonedDateTime = zonedDateTimeOptional.get();
            return zonedDateTime.toLocalDateTime();
        }
        return null;
    }

    public static LocalDateTime nextExecution(String expression) {
        CronParser parser = new CronParser(CRON_DEFINITION);
        Cron quartzCron = parser.parse(expression);
        ZonedDateTime now = ZonedDateTime.now();
        ExecutionTime executionTime = ExecutionTime.forCron(quartzCron);
        Optional<ZonedDateTime> zonedDateTimeOptional = executionTime.nextExecution(now);
        if (zonedDateTimeOptional.isPresent()) {
            ZonedDateTime zonedDateTime = zonedDateTimeOptional.get();
            return zonedDateTime.toLocalDateTime();
        }
        return null;
    }
}

测试：

表达式：34 20 18 L 1/3 ?