这篇文章主要介绍了详解javascript判断crontab表达式是否合法的相关资料,需要的朋友可以参考下
Javascript判断Crontab表达式是否合法
这段时间在做Quartz任务调度，使用的Crontab表达式实现的。Crontab由前端页面输入，作为参数穿入后台。
虽然Quartz具有校验Crontab表达式的方法，如下：
boolean cronExpressionFlag = CronExpression.isValidExpression(crontab);
但是我一直想在前端直接验证，即不需要通过异步的方式向后台获取验证结果，找了好久，发现没有现成的框架可以使用，于是自己根据网上搜索到的资料，写了这个js脚本。
这个脚本目前对日和星期的判断还有点小问题，不过不影响使用。
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以后如果有时间，继续完善这个脚本，废话不多说了，上代码：
function cronValidate() {
var cron = $("#cron").val();
var result = CronExpressionValidator.validateCronExpression(cron);
if(result == true){
alert("格式正确");
}
else{
alert("格式错误");
}
return CronExpressionValidator.validateCronExpression(cron);
}
function CronExpressionValidator() {
}
CronExpressionValidator.validateCronExpression = function(value) {
var results = true;
if (value == null || value.length == 0) {
return false;
}
// split and test length
var expressionArray = value.split(" ");
var len = expressionArray.length;
if ((len != 6) && (len != 7)) {
return false;
}
// check only one question mark
var match = value.match(/\?/g);
if (match != null && match.length > 1) {
return false;
}
// check only one question mark
var dayOfTheMonthWildcard = "";
// if appropriate length test parts
// [0] Seconds 0-59 , - * /
if (CronExpressionValidator.isNotWildCard(expressionArray[0], /[\*]/gi)) {
if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[0], [0, 59], "seconds")) {
return false;
}
}
// [1] Minutes 0-59 , - * /
if (CronExpressionValidator.isNotWildCard(expressionArray[1], /[\*]/gi)) {
if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[1], [0, 59], "minutes")) {
return false;
}
}
// [2] Hours 0-23 , - * /
if (CronExpressionValidator.isNotWildCard(expressionArray[2], /[\*]/gi)) {
if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[2], [0, 23], "hours")) {
return false;
}
}
// [3] Day of month 1-31 , - * ? / L W C
if (CronExpressionValidator.isNotWildCard(expressionArray[3], /[\*\?]/gi)) {
if (!CronExpressionValidator.segmentValidator("([0-9LWC\\\\,-\\/])", expressionArray[3], [1, 31], "days of the month")) {
return false;
}
} else {
dayOfTheMonthWildcard = expressionArray[3];
}
// [4] Month 1-12 or JAN-DEC , - * /
if (CronExpressionValidator.isNotWildCard(expressionArray[4], /[\*]/gi)) {
expressionArray[4] = CronExpressionValidator.convertMonthsToInteger(expressionArray[4]);
if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[4], [1, 12], "months")) {
return false;
}
}
// [5] Day of week 1-7 or SUN-SAT , - * ? / L C #
if (CronExpressionValidator.isNotWildCard(expressionArray[5], /[\*\?]/gi)) {
expressionArray[5] = CronExpressionValidator.convertDaysToInteger(expressionArray[5]);
if (!CronExpressionValidator.segmentValidator("([0-9LC#\\\\,-\\/])", expressionArray[5], [1, 7], "days of the week")) {
return false;
}
} else {
if (dayOfTheMonthWildcard == String(expressionArray[5])) {
return false;
}
}
// [6] Year empty or 1970-2099 , - * /
if (len == 7) {
if (CronExpressionValidator.isNotWildCard(expressionArray[6], /[\*]/gi)) {
if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[6], [1970, 2099], "years")) {
return false;
}
}
}
return true;
}
// ----------------------------------
// isNotWildcard 静态方法;
// ----------------------------------
CronExpressionValidator.isNotWildCard = function(value, expression) {
var match = value.match(expression);
return (match == null || match.length == 0) ? true : false;
}
// ----------------------------------
// convertDaysToInteger 静态方法;
// ----------------------------------
CronExpressionValidator.convertDaysToInteger = function(value) {
var v = value;
v = v.replace(/SUN/gi, "1");
v = v.replace(/MON/gi, "2");
v = v.replace(/TUE/gi, "3");
v = v.replace(/WED/gi, "4");
v = v.replace(/THU/gi, "5");
v = v.replace(/FRI/gi, "6");
v = v.replace(/SAT/gi, "7");
return v;
}
// ----------------------------------
// convertMonthsToInteger 静态方法;
// ----------------------------------
CronExpressionValidator.convertMonthsToInteger = function(value) {
var v = value;
v = v.replace(/JAN/gi, "1");
v = v.replace(/FEB/gi, "2");
v = v.replace(/MAR/gi, "3");
v = v.replace(/APR/gi, "4");
v = v.replace(/MAY/gi, "5");
v = v.replace(/JUN/gi, "6");
v = v.replace(/JUL/gi, "7");
v = v.replace(/AUG/gi, "8");
v = v.replace(/SEP/gi, "9");
v = v.replace(/OCT/gi, "10");
v = v.replace(/NOV/gi, "11");
v = v.replace(/DEC/gi, "12");
return v;
}
// ----------------------------------
// segmentValidator 静态方法;
// ----------------------------------
CronExpressionValidator.segmentValidator = function(expression, value, range, segmentName) {
var v = value;
var numbers = new Array();
// first, check for any improper segments
var reg = new RegExp(expression, "gi");
if (!reg.test(v)) {
return false;
}
// check duplicate types
// check only one L
var dupMatch = value.match(/L/gi);
if (dupMatch != null && dupMatch.length > 1) {
return false;
}
// look through the segments
// break up segments on ','
// check for special cases L,W,C,/,#,-
var split = v.split(",");
var i = -1;
var l = split.length;
var match;
while (++i < l) {
// set vars
var checkSegment = split[i];
var n;
var pattern = /(\w*)/;
match = pattern.exec(checkSegment);
// if just number
pattern = /(\w*)\-?\d+(\w*)/;
match = pattern.exec(checkSegment);
if (match
&& match[0] == checkSegment
&& checkSegment.indexOf("L") == -1
&& checkSegment.indexOf("l") == -1
&& checkSegment.indexOf("C") == -1
&& checkSegment.indexOf("c") == -1
&& checkSegment.indexOf("W") == -1
&& checkSegment.indexOf("w") == -1
&& checkSegment.indexOf("/") == -1
&& (checkSegment.indexOf("-") == -1 || checkSegment
.indexOf("-") == 0) && checkSegment.indexOf("#") == -1) {
n = match[0];
if (n && !(isNaN(n)))
numbers.push(n);
else if (match[0] == "0")
numbers.push(n);
continue;
}
// includes L, C, or w
pattern = /(\w*)L|C|W(\w*)/i;
match = pattern.exec(checkSegment);
if (match
&& match[0] != ""
&& (checkSegment.indexOf("L") > -1
|| checkSegment.indexOf("l") > -1
|| checkSegment.indexOf("C") > -1
|| checkSegment.indexOf("c") > -1
|| checkSegment.indexOf("W") > -1 || checkSegment
.indexOf("w") > -1)) {
// check just l or L
if (checkSegment == "L" || checkSegment == "l")
continue;
pattern = /(\w*)\d+(l|c|w)?(\w*)/i;
match = pattern.exec(checkSegment);
// if something before or after
if (!match || match[0] != checkSegment) {
continue;
}
// get the number
var numCheck = match[0];
numCheck = numCheck.replace(/(l|c|w)/ig, "");
n = Number(numCheck);
if (n && !(isNaN(n)))
numbers.push(n);
else if (match[0] == "0")
numbers.push(n);
continue;
}
var numberSplit;
// includes /
if (checkSegment.indexOf("/") > -1) {
// take first #
numberSplit = checkSegment.split("/");
if (numberSplit.length != 2) {
continue;
} else {
n = numberSplit[0];
if (n && !(isNaN(n)))
numbers.push(n);
else if (numberSplit[0] == "0")
numbers.push(n);
continue;
}
}
// includes #
if (checkSegment.indexOf("#") > -1) {
// take first #
numberSplit = checkSegment.split("#");
if (numberSplit.length != 2) {
continue;
} else {
n = numberSplit[0];
if (n && !(isNaN(n)))
numbers.push(n);
else if (numberSplit[0] == "0")
numbers.push(n);
continue;
}
}
// includes -
if (checkSegment.indexOf("-") > 0) {
// take both #
numberSplit = checkSegment.split("-");
if (numberSplit.length != 2) {
continue;
} else if (Number(numberSplit[0]) > Number(numberSplit[1])) {
continue;
} else {
n = numberSplit[0];
if (n && !(isNaN(n)))
numbers.push(n);
else if (numberSplit[0] == "0")
numbers.push(n);
n = numberSplit[1];
if (n && !(isNaN(n)))
numbers.push(n);
else if (numberSplit[1] == "0")
numbers.push(n);
continue;
}
}
}
// lastly, check that all the found numbers are in range
i = -1;
l = numbers.length;
if (l == 0)
return false;
while (++i < l) {
// alert(numbers[i]);
if (numbers[i] < range[0] || numbers[i] > range[1]) {
return false;
}
}
return true;
} 
