的Cron人类可读的字符串[关闭]
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22-07-2019 - |
题
我使用Quartz与Java调度作业。一件事是,我一个数据库中存储的cron表达式,我想将它们呈现给用户,但在一个更可读的形式。所以我想知道是否有可能一个cron表达式转换为人类可读的字符串的实用程序。是这样的:
“” 0 30 10-13? *周三,周五” 会变成 “大火在10:30,11:30,12:30,13:30,每星期三和星期五。”
解决方案
一个Java库,cron的表达式转换为人类可读的字符串: https://github.com/RedHogs/cron-parser一>
其他提示
嗯,是我没明白你的问题。但我应该有一个好一点的解释我的答案。
没有我不知道的任何工具,将帮助你在“人”可读形式的cron表达式。但是,通过让访问CronExpression你可以创建你自己的。
尝试调用
cronTrigger.getExpressionSummary()
上cron表达式:
"0/2 * * 4 * ?"
它返回以下字符串:
seconds: 0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52,54,56,58
minutes: *
hours: *
daysOfMonth: 4
months: *
daysOfWeek: ?
lastdayOfWeek: false
nearestWeekday: false
NthDayOfWeek: 0
lastdayOfMonth: false
calendardayOfWeek: false
calendardayOfMonth: false
years: *
通过访问该CronExpression对象,你可以创建自己的“人” explenation。
时钟守护utils的可以是用于此任务是有用的,因为提供了人可读的描述,并且不需要一个完全成熟的调度,为他们提供。是有据可查的,并支持多个cron的格式。
下面从文档的代码片断:
//create a descriptor for a specific Locale
CronDescriptor descriptor = CronDescriptor.instance(Locale.UK);
//parse some expression and ask descriptor for description
String description = descriptor.describe(parser.parse("*/45 * * * * *"));
//description will be: "every 45 seconds"
这里有一个我开始。它使用我的用户(可能)理解的语言。
它不会与像的DAYOFMONTH令牌“1,13,16-23,L”令牌的混合物做的很好,但我相信,我还会有一些时间花费在它之前我的用户成为复杂:
package com.tacteonltd.control.cron; import java.util.StringTokenizer; import com.tacteonltd.control.string.STRING; import com.tacteonltd.control.time.TIME; public class CRON { public static String humanReadable(String value){ StringBuffer sb = new StringBuffer(); try{ StringTokenizer tokens = new StringTokenizer(value, " ", false); humanizeSeconds(tokens.nextToken(), sb);sb.append("\n"); humanizeMinutes(tokens.nextToken(), sb);sb.append("\n"); humanizeHours(tokens.nextToken(), sb);sb.append("\n"); String dom = tokens.nextToken(); String month = tokens.nextToken(); String dow = tokens.nextToken(); humanizeDOMs(dom, dow, sb);sb.append("\n"); humanizeMonths(month, sb);sb.append("\n"); humanizeDOWs(dow, dom, sb); }catch(Throwable t){ t.printStackTrace(); } return sb.toString(); } private static void humanizeDOWs(String value, String dom, StringBuffer sb){ value=value.trim(); if(STRING.isNumeric(value)){ sb.append("and the " + value + postFix(value) + " day-of-the-week("+TIME.getWeekDayName(Integer.parseInt(value))+"). "); } else if(value.equals("*")) { sb.append("and every day-of-the-week. "); } else if(value.equals("?")) { sb.append("and whatever day-of-the-week it is for day"+(STRING.isNumeric(dom) ? "":"s")+"-of-the-month :"+(STRING.isNumeric(dom) ? dom:"that match"+(STRING.isNumeric(dom) ? "es":"")+" " + dom + ".")); } else if(value.indexOf("/")>-1){ String first = value.substring(0, value.indexOf("/")); String every = value.substring(value.indexOf("/") + 1); sb.append("and the " + first + postFix(first) + " day-of-the-week and every " + every + " day" + (Integer.parseInt(every) == 1 ? "":"s") + " following. "); } else if(value.indexOf(",")>-1){ StringTokenizer tokens = new StringTokenizer(value, ",", false); sb.append("and the following days of the week: "); int added = 0; while(tokens.hasMoreTokens()){ String token = tokens.nextToken(); sb.append((added==0 ? "":", ") + token);added++; } sb.append("."); } else if(value.indexOf("-")>-1){ StringTokenizer tokens = new StringTokenizer(value, "-", false); sb.append("and for every day of the week from " + tokens.nextToken() + " through " + tokens.nextToken() + ". "); } else { sb.append("and the following days of the week: " + value + "."); } } private static void humanizeMonths(String value, StringBuffer sb){ value=value.trim(); if(STRING.isNumeric(value)){ sb.append("the " + value + postFix(value) + " month("+TIME.getMonthName(Integer.parseInt(value))+"), "); } else if(value.equals("*")) { sb.append("every month, "); } else if(value.indexOf("/")>-1){ String first = value.substring(0, value.indexOf("/")); String every = value.substring(value.indexOf("/") + 1); sb.append("the " + first + postFix(first) + " month("+TIME.getMonthName(Integer.parseInt(value))+") and every " + every + " month" + (Integer.parseInt(every) == 1 ? "":"s") + " following, "); } else if(value.indexOf(",")>-1){ StringTokenizer tokens = new StringTokenizer(value, ",", false); sb.append("the following months: "); int added = 0; while(tokens.hasMoreTokens()){ sb.append((added==0 ? "":", ") + tokens.nextToken());added++; } } } private static void humanizeDOMs(String value, String dow, StringBuffer sb){ value=value.trim(); if(STRING.isNumeric(value)){ sb.append("the " + value + postFix(value) + " day-of-the-month, "); } else if(value.equals("*")) { sb.append("every day-of-the-month, "); } else if(value.equals("?")) { sb.append("whatever day-of-the-month falls upon " + dow + " , "); } else if(value.indexOf("-")>-1){ StringTokenizer tokens = new StringTokenizer(value, "-", false); String from = tokens.nextToken(); String through = tokens.nextToken(); int year = TIME.getYear(System.currentTimeMillis()); int month = TIME.getMonth(System.currentTimeMillis()); String last_dom = "" + TIME.getLastDOM(year, month); sb.append("for every day of the month from " + from + " through " + (through.equals("L") ? "the last("+year +"." +month + "."+last_dom+")":through) ); } else if(value.indexOf("/")>-1){ String first = value.substring(0, value.indexOf("/")); String every = value.substring(value.indexOf("/") + 1); sb.append("the " + first + postFix(first) + " day-of-the-month and every " + every + " day" + (Integer.parseInt(every) == 1 ? "":"s") + " following, "); } else if(value.indexOf(",")>-1){ StringTokenizer tokens = new StringTokenizer(value, ",", false); sb.append("the following days of the month: "); int added = 0; while(tokens.hasMoreTokens()){ String token = tokens.nextToken(); if(token.equals("L")){ int year = TIME.getYear(System.currentTimeMillis()); int month = TIME.getMonth(System.currentTimeMillis()); String last_dom = "" + TIME.getLastDOM(year, month); sb.append((added==0 ? "":", ") + "the last("+year +"." +month + "."+last_dom+")"); } else{ sb.append((added==0 ? "":", ") + token);added++; } } } } private static void humanizeSeconds(String value, StringBuffer sb){ value=value.trim(); if(STRING.isNumeric(value)){ sb.append("on the " + value + postFix(value) + " second, "); } else if(value.equals("*")) { sb.append("on every second, "); } else if(value.indexOf("/")>-1){ String first = value.substring(0, value.indexOf("/")); String every = value.substring(value.indexOf("/") + 1); sb.append("on the " + first + postFix(first) + " second and every " + every + " second" + (Integer.parseInt(every) == 1 ? "":"s") + " following, "); } else if(value.indexOf("-")>-1){ StringTokenizer tokens = new StringTokenizer(value, "-", false); sb.append("for every second from " + tokens.nextToken() + " through " + tokens.nextToken() + " "); } else if(value.indexOf(",")>-1){ StringTokenizer tokens = new StringTokenizer(value, ",", false); sb.append("on the following seconds: "); int added = 0; while(tokens.hasMoreTokens()){ sb.append((added==0 ? "":", ") + tokens.nextToken());added++; } } } private static void humanizeMinutes(String value, StringBuffer sb){ value=value.trim(); if(STRING.isNumeric(value)){ sb.append("the " + value + postFix(value) + " minute, "); } else if(value.equals("*")) { sb.append("every minute, "); } else if(value.indexOf("/")>-1){ String first = value.substring(0, value.indexOf("/")); String every = value.substring(value.indexOf("/") + 1); sb.append("the " + first + postFix(first) + " minute and every " + every + " minute" + (Integer.parseInt(every) == 1 ? "":"s") + " following, "); } else if(value.indexOf("-")>-1){ StringTokenizer tokens = new StringTokenizer(value, "-", false); sb.append("for every minute from " + tokens.nextToken() + " through " + tokens.nextToken() + " "); } else if(value.indexOf(",")>-1){ StringTokenizer tokens = new StringTokenizer(value, ",", false); sb.append("the following minutes: "); int added = 0; while(tokens.hasMoreTokens()){ sb.append((added==0 ? "":", ") + tokens.nextToken());added++; } } } private static void humanizeHours(String value, StringBuffer sb){ value=value.trim(); if(STRING.isNumeric(value)){ sb.append("the " + value + postFix(value) + " hour, "); } else if(value.equals("*")) { sb.append("every hour, "); } else if(value.indexOf("/")>-1){ String first = value.substring(0, value.indexOf("/")); String every = value.substring(value.indexOf("/") + 1); sb.append("the " + first + postFix(first) + " hour and every " + every + " hour" + (Integer.parseInt(every) == 1 ? "":"s") + " following, "); } else if(value.indexOf("-")>-1){ StringTokenizer tokens = new StringTokenizer(value, "-", false); sb.append("for every hour from " + tokens.nextToken() + " through " + tokens.nextToken() + " "); } else if(value.indexOf(",")>-1){ StringTokenizer tokens = new StringTokenizer(value, ",", false); sb.append("the following hours: "); int added = 0; while(tokens.hasMoreTokens()){ sb.append((added==0 ? "":", ") + tokens.nextToken());added++; } } } private static String postFix(String value){ String post = null; if(value.substring(value.length()-1).equals("1"))post = "st"; else if(value.substring(value.length()-1).equals("2"))post = "nd"; else if(value.substring(value.length()-1).equals("3"))post = "rd"; else post="th"; return post; } }
在CronTrigger创建从cron表达式字符串一个CronExpression对象。 但你不能访问它。但是,通过使用反射可以:
Class c = cronTrigger.getClass();
Field f = c.getDeclaredField("cronEx");
f.setAccessible(true);
CronExpression cronEx = (CronExpression) f.get(cronTrigger);
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