js生日计算年龄_java通过身份证号计算周岁年龄(附js计算)

最近项目上有一个需要根据身份证获取老人周岁的功能，本以为当前年直接减去身份证的出生年就好了。结果测试提了过了生日就是+1岁，没过生日才是正确的。于是呼，哗哗的改代码。下面分别贴出java计算和js计算：

public Integer handleIdentityAge(String identity,Integer year,Integer month,Integer day){        if(identity.length()<10){            return 0;        }        Integer selectYear=Integer.valueOf(identity.substring(6,10));        Integer selectMonth=Integer.valueOf(identity.substring(10,12));        Integer selectDay = Integer.valueOf(identity.substring(12, 14));        Integer yearMinus = year - selectYear;        Integer monthMinus = month - selectMonth;        Integer dayMinus = day - selectDay;        Integer age = yearMinus;        if(yearMinus<0){            age = 0;        }else if (yearMinus == 0) {            age = 0;        } else if (yearMinus > 0) {            if (monthMinus == 0) {                if (dayMinus < 0) {                    age = age - 1;                }            } else if (monthMinus > 0) {                age = age + 1;            }        }        return age;    }

function calculatingAge (identity) {  if(identity.length < 10) {    return "";  }  debugger  var birthYear = identity.substr(6, 4);  var birthMonth = identity.substr(10, 2);  var birthDay = identity.substr(12, 2);  var d = new Date();  var nowYear = d.getFullYear();  var nowMonth = d.getMonth() + 1;  var nowDay = d.getDate();  let returnAge = 0;  let result = 0;  //1997-11-16  if(nowYear == birthYear) {    returnAge = 0; //同年 则为0岁   } else {    var ageDiff = nowYear - birthYear; //年之差      if(ageDiff > 0) {      if(nowMonth == birthMonth) {        var dayDiff = nowDay - birthDay; //日之差        if(dayDiff < 0) {          returnAge = ageDiff - 1;        } else {          returnAge = ageDiff;        }      } else {        var monthDiff = nowMonth - birthMonth; //月之差          if(monthDiff < 0) {          returnAge = ageDiff - 1;        } else {          returnAge = ageDiff;        }      }    } else {      returnAge = -1; //返回-1 表示出生日期输入错误 晚于今天      }  }  return returnAge;}

以上两种方式都是根据身份证号计算周岁，避免重复造轮子，可以直接复制使用。