Existe-t-il un code Java pour créer une expression Cron ?

Question

J'ai besoin d'un code Java pour créer une expression cron basée sur les entrées de l'utilisateur. Les entrées de l'utilisateur sont le temps, la fréquence et le nombre d'exécutions.

Answer 1

Je ne fais que compléter le commentaire qui dit de le créer soi-même.

Voici un exemple : Demandez à l'utilisateur les valeurs et passez-les dans la méthode suivante, la Javadoc explique ce qui est autorisé dans quelle valeur (tiré de http://en.wikipedia.org/wiki/Cron#Format ).

Cette méthode n'est pas testée et ne valide aucune des chaînes d'entrée, mais je suis sûr que vous pouvez le faire.

/**
 * 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);
}

Format Cron Informations tirées d'ici : http://en.wikipedia.org/wiki/Cron#Format

Answer 2

Je pense que vous pouvez utiliser cron-utils qui apporte une classe CronBuilder et permet d'exporter vers plusieurs formats. Cette fonctionnalité est disponible à partir de la version 4.0.0.

Un exemple tiré du README :

//Create a cron expression. CronMigrator will ensure you remain cron provider agnostic
import static com.cronutils.model.field.expression.FieldExpressionFactory.*;
Cron cron = CronBuilder.cron(CronDefinitionBuilder.instanceDefinitionFor(CronType.QUARTZ))
.withYear(always())
.withDoM(between(1, 3))
.withMonth(always())
.withDoW(questionMark())
.withHour(always())
.withMinute(always())
.withSecond(on(0))
.instance();
//Obtain the string expression
String cronAsString = cron.asString();//0 * * 1-3 * ? *
//Migrate to Unix format
cron = CronMapper.fromQuartzToUnix().map(cron);
cronAsString = cron.asString();//* * 1-3 * *

Answer 3

L'extrait soumis par edwardsmatt ci-dessus ne fonctionne pas correctement avec la CronExpression de Quartz. Voici une version corrigée qui fonctionne :

/**
 * 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);
}

Answer 4

Vous pouvez modifier l'implémentation ci-dessous en fonction de vos besoins.

import java.io.Serializable;

public class CronExpressionCreator implements Serializable {

    private static final long serialVersionUID = -1676663054009319677L;

    public static void main(String[] args) {
        CronExpressionCreator pCron = new CronExpressionCreator();
        pCron.setTime("12:00 PM");
        pCron.setMON(true);
        pCron.setStartDate("12-05-2011");
        System.out.println(pCron.getCronExpression());
    }

    public String getCronExpression() {
        String time = getTime();
        String[] time1 = time.split("\\:");
        String[] time2 = time1[1].split("\\ ");

        String hour = "";
        if (time2[1].equalsIgnoreCase("PM")) {
            Integer hourInt = Integer.parseInt(time1[0]) + 12;
            if (hourInt == 24) {
                hourInt = 0;
            }
            hour = hourInt.toString();
        } else {
            hour = time1[0];
        }

        String minutes = time2[0];
        String cronExp = "";
        if (isRecurring()) {
            String daysString = "";
            StringBuilder sb = new StringBuilder(800);
            boolean moreConditions = false;

            if (isSUN()) {
                sb.append("SUN");
                moreConditions = true;
            }

            if (isMON()) {
                if (moreConditions) {
                    sb.append(",");
                }
                sb.append("MON");
                moreConditions = true;
            }

            if (isTUE()) {
                if (moreConditions) {
                    sb.append(",");
                }

                sb.append("TUE");
                moreConditions = true;
            }

            if (isWED()) {
                if (moreConditions) {
                    sb.append(",");
                }

                sb.append("WED");
                moreConditions = true;
            }

            if (isTHU()) {
                if (moreConditions) {
                    sb.append(",");
                }
                sb.append("THU");
                moreConditions = true;
            }

            if (isFRI()) {
                if (moreConditions) {
                    sb.append(",");
                }
                sb.append("FRI");
                moreConditions = true;
            }

            if (isSAT()) {
                if (moreConditions) {
                    sb.append(",");
                }
                sb.append("SAT");
                moreConditions = true;
            }

            daysString = sb.toString();

            cronExp = "0 " + minutes + " " + hour + " ? * " + daysString;
        } else {
            String startDate = getStartDate();
            String[] dateArray = startDate.split("\\-");
            String day = dateArray[0];
            if (day.charAt(0) == '0') {
                day = day.substring(1);
            }

            String month = dateArray[1];

            if (month.charAt(0) == '0') {
                month = month.substring(1);
            }

            String year = dateArray[2];
            cronExp = "0 " + minutes + " " + hour + " " + day + " " + month
            + " ? " + year;

        }
        return cronExp;
    }

    String startDate;
    String time;
    boolean recurring;
    boolean SUN;
    boolean MON;
    boolean TUE;
    boolean WED;
    boolean THU;
    boolean FRI;
    boolean SAT;

    /**
     * @return the startDate
     */
    public String getStartDate() {
        return startDate;
    }

    /**
     * The date set should be of the format (MM-DD-YYYY for example 25-04-2011)
     * 
     * @param startDate
     *            the startDate to set
     */
    public void setStartDate(String startDate) {
        this.startDate = startDate;
    }

    /**
     * @return the time
     */
    public String getTime() {
        return time;
    }

    /**
     * The time set should be of the format (HH:MM AM/PM for example 12:15 PM)
     * 
     * @param time
     *            the time to set
     */
    public void setTime(String time) {
        this.time = time;
    }

    public boolean isRecurring() {
        return recurring;
    }

    public void setRecurring(boolean recurring) {
        this.recurring = recurring;
    }

    public boolean isSUN() {
        return SUN;
    }

    public void setSUN(boolean sUN) {
        SUN = sUN;
    }

    public boolean isMON() {
        return MON;
    }

    /**
     * @param mON
     *            the mON to set
     */
    public void setMON(boolean mON) {
        MON = mON;
    }

    public boolean isTUE() {
        return TUE;
    }

    public void setTUE(boolean tUE) {
        TUE = tUE;
    }

    public boolean isWED() {
        return WED;
    }

    public void setWED(boolean wED) {
        WED = wED;
    }

    public boolean isTHU() {
        return THU;
    }

    public void setTHU(boolean tHU) {
        THU = tHU;
    }

    public boolean isFRI() {
        return FRI;
    }

    public void setFRI(boolean fRI) {
        FRI = fRI;
    }

    public boolean isSAT() {
        return SAT;
    }

    public void setSAT(boolean sAT) {
        SAT = sAT;
    }

    public int hashCode() {
        return this.getCronExpression().hashCode();
    }

    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (obj instanceof CronExpressionCreator) {
            if (((CronExpressionCreator) obj).getCronExpression()
                    .equalsIgnoreCase(this.getCronExpression())) {
                return true;
            }
        } else {
            return false;
        }
        return false;

    }

}