详解Javascript判断Crontab表达式是否合法

boolean cronExpressionFlag = CronExpression.isValidExpression(crontab);

 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;   }