如何从字符串中提取子字符串？

Question

Actually i have to find today's birthday from contacts. I have the string variable like String value="2014-06-24".

I want to get the month and date of the of the string variable to compare with today date to find the birthday. Or it has any other methods?

Answer 1

Use SimpleDateFormate, if you don not get you can use bellow given method

String[] arr = yourStringDate.split("-");
String year = arr[0];
String month = arr[1];
String day = arr[2];

Answer 2

You can use SimpleDateFormat to parse dates like this:

SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
try {
    Date date = dateFormat.parse("2014-06-24");
} catch (ParseException e) {
    // This exception occurs when the String could not be parsed!
    e.printStackTrace();
}

When you have Date objects you can compare them with before() and after() like this:

if(dateA.after(dateB)) {
    // dateA is after dateB
} else {
    // dateA is before dateB
}

You can use a Calendar object to get further information from the Date object.

Calendar calendar = Calendar.getInstance();
calendar.setTime(date);

int month = calendar.get(Calendar.MONTH) + 1;
int day = calendar.get(Calendar.DAY_OF_MONTH);

Answer 3

You can use following way to find date and month from value string:

Date date = System.currentTimeMillis();
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
try {
    date = formatter.parse(value);
} catch (ParseException e) {
    // This exception occurs when the String could not be parsed!
    e.printStackTrace();
}

Calendar cal = Calendar.getInstance();
cal.setTime(date);
int birthDay = cal.get(Calendar.DATE);
int birthMonth = cal.get(Calendar.MONTH);

then

Calendar currentCal = Calendar.getInstance();
Date today =  currentCal.getTime();

then you can use date comparison like :

if(date.before(today) || date.after(today)) and so on for your next operation.