第一次写项目。用到的一些关于日期的操作。发现网上居然没有日期减天数的到日期的算法，所以就自己写了一个：
//将数字转化成字符串
public static String ToStringNum2(int num) {
String stringNum = null;
if (String.valueOf(num).length() == 1) {
stringNum = "0" + String.valueOf(num);
return stringNum;
}
if (String.valueOf(num).length() == 2) {
stringNum = String.valueOf(num);
return stringNum;
}
System.out.println("转化数字出错");
return null;
}
//返回当前日期
public static String NowTime() {
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");// 设置日期格式
String strDate = df.format(new Date());
return strDate;// new Date()为获取当前系统时间
}
// 判断年份是否为闰年
private static boolean isPrime(int year) {
boolean leadyear;
if (year % 4 == 0 && year % 100 != 0) {
leadyear = true;
} else if (year % 400 == 0) {
leadyear = true;
} else {
leadyear = false;
}
return leadyear;
}
// 计算间隔天数
public static int calInterval(String sDate, String eDate) {
// 时间间隔，初始为0
int interval = 0;
boolean flag = true;
int[] primeMonth = new int[]{31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int[] notPrimeMonth = new int[]{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/* 将两个日期赋给日历实例，并获取年、月、日相关字段值 */
int sYears = Integer.parseInt(sDate.substring(0, 4));// 2016-10-01
int sMonths = Integer.parseInt(sDate.substring(5, 7));
int sDays = Integer.parseInt(sDate.substring(8, 10));
int eYears = Integer.parseInt(eDate.substring(0, 4));// 2016-10-01
int eMonths = Integer.parseInt(eDate.substring(5, 7));
int eDays = Integer.parseInt(eDate.substring(8, 10));
// 从sYears开始累加到eYears
for (int i = sYears; i < eYears; i++) {
interval += isPrime(i) ? 366 : 365;
}
// 如果eYears是闰年,则flag=true,后面调用primeMonth[12]
flag = isPrime(eYears);
// 加上eMonths到1月的天数
for (int i = 1; i < eMonths; i++) {
if (flag) {
interval += primeMonth[i - 1];
} else {
interval += notPrimeMonth[i - 1];
}
}
// 如果sYears是闰年,则flag=true,后面调用primeMonth[12]
flag = isPrime(sYears);
// 减去sMonths到1月的天数
for (int i = 1; i < sMonths; i++) {
if (flag) {
interval -= primeMonth[i - 1];
} else {
interval -= notPrimeMonth[i - 1];
}
}
interval = interval + eDays - sDays;
return interval;
}
//计算多少天之后的日期
public static String addDate(String initDate, int diffDays) {
// 时间间隔，初始为0
int interval = 0;
boolean flag = true;
int[] normalMonthDays = new int[]{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/* 将两个日期赋给日历实例，并获取年、月、日相关字段值 */
int initDateYears = Integer.parseInt(initDate.substring(0, 4));
int initDateMonths = Integer.parseInt(initDate.substring(5, 7));
int initDateDays = Integer.parseInt(initDate.substring(8, 10));
int reDateYears = initDateYears;
int reDateMonths = initDateMonths;
int reDateDays = initDateDays;
//1.get years (days >=366 or 365)
int daysAyear = 365;
if (isPrime(reDateYears) && (reDateMonths < 3)) {//if leap year
daysAyear = 366;
}
while ((diffDays / daysAyear) != 0) {
diffDays = diffDays - daysAyear;
reDateYears++;
if (isPrime(reDateYears)) {
daysAyear = 366;
} else {
daysAyear = 365;
}
}
//2.get months (days < 366 or 365)
if (isPrime(reDateYears)) {//if leap year
normalMonthDays[2] = 29;
} else {
normalMonthDays[2] = 28;
}
while ((diffDays / normalMonthDays[reDateMonths]) != 0) {
diffDays = diffDays - normalMonthDays[reDateMonths];
reDateMonths++;
if (reDateMonths >= 13) {
reDateYears++;
if (isPrime(reDateYears)) {
normalMonthDays[2] = 29;
} else {
normalMonthDays[2] = 28;
}
reDateMonths = reDateMonths % 12;
}
}
//3.get days
if (isPrime(reDateYears)) {
normalMonthDays[2] = 29;
} else {
normalMonthDays[2] = 28;
}
if (diffDays + reDateDays <= normalMonthDays[reDateMonths]) {
reDateDays = diffDays + reDateDays;
} else {
reDateDays = diffDays + reDateDays - normalMonthDays[reDateMonths];
reDateMonths++;
if (reDateMonths > 12) {
reDateYears++;
reDateMonths = reDateMonths % 12;
}
}
String reDate = String.valueOf(reDateYears) + "-" + ToStringNum2(reDateMonths) + "-" + ToStringNum2(reDateDays);
return reDate;
}
//计算多少天之前的日期
public static String minusDate(String initDate, int diffDays) {
// 时间间隔，初始为0
int interval = 0;
boolean flag = true;
int[] normalMonthDays = new int[]{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/* 将两个日期赋给日历实例，并获取年、月、日相关字段值 */
int initDateYears = Integer.parseInt(initDate.substring(0, 4));
int initDateMonths = Integer.parseInt(initDate.substring(5, 7));
int initDateDays = Integer.parseInt(initDate.substring(8, 10));
int reDateYears = initDateYears;
int reDateMonths = initDateMonths;
int reDateDays = initDateDays;
if (reDateDays > diffDays) {
reDateDays -= diffDays;
} else if (reDateDays == diffDays) {
reDateMonths--;
if (reDateMonths < 1) {
reDateYears--;
reDateMonths = 12;
}
if (isPrime(reDateYears)) {
normalMonthDays[2] = 29;
} else {
normalMonthDays[2] = 28;
}
reDateDays = normalMonthDays[reDateMonths];
} else {
diffDays = diffDays - reDateDays;
reDateMonths--;
if (reDateMonths < 1) {
reDateYears--;
reDateMonths = 12;
}
if (isPrime(reDateYears)) {
normalMonthDays[2] = 29;
} else {
normalMonthDays[2] = 28;
}
reDateDays = normalMonthDays[reDateMonths];
///;
int daysAyear = 365;
if (isPrime(reDateYears) && (reDateMonths > 2)) {//if leap year
daysAyear = 366;
} else if ((reDateMonths == 2) && (reDateDays == 29)) {
daysAyear = 366;
}
while ((diffDays / daysAyear) != 0) {
diffDays = diffDays - daysAyear;
reDateYears--;
if (isPrime(reDateYears)) {
daysAyear = 366;
} else {
daysAyear = 365;
}
}
//2.get months (days < 366 or 365)
if (isPrime(reDateYears)) {//if leap year
normalMonthDays[2] = 29;
} else {
normalMonthDays[2] = 28;
}
while ((diffDays / normalMonthDays[reDateMonths]) != 0) {
diffDays = diffDays - normalMonthDays[reDateMonths];
reDateMonths--;
if (reDateMonths < 1) {
reDateYears--;
if (isPrime(reDateYears)) {
normalMonthDays[2] = 29;
} else {
normalMonthDays[2] = 28;
}
reDateMonths = 12;
}
}
//3.get days
if (isPrime(reDateYears)) {
normalMonthDays[2] = 29;
} else {
normalMonthDays[2] = 28;
}
reDateDays = normalMonthDays[reDateMonths];
reDateDays -= diffDays;
}
String reDate = String.valueOf(reDateYears) + "-" + ToStringNum2(reDateMonths) + "-" + ToStringNum2(reDateDays);
return reDate;
}
