在Java中经过一定时间后获取日期

Question

Basically I have a date stored as text in this format: 16/09/2014 in SQLite Browser. I wonder is there any way to get the date after one day, one week, one month and one year of each records in the database using Java.

I retrieved and display the date retrieved from database in a listview:

viewHolder.txt_ddate.setText("Next Payment On: "
                + _recurlist.get(position).getRecurringStartDate().trim());

So I was thinking to use Java technique to get the dates I mentioned above. I have researched on this and found Documentation but I not sure how to implement it into my problem.

Any guides? Thanks in advance.

Answer 1

Use a Calendar object like in your example, which provides the add method.

String dateAsString = "16/09/2014";
DateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
Calendar c = Calendar.getInstance();
c.setTime(formatter.parse(dateAsString));

c.add(Calendar.DAY_OF_MONTH, 1);
System.out.println("After one day: " + formatter.format(c.getTimeInMillis()));
c.add(Calendar.DAY_OF_MONTH, -1);

c.add(Calendar.WEEK_OF_YEAR, 1);
System.out.println("After one week: " + formatter.format(c.getTimeInMillis()));
c.add(Calendar.WEEK_OF_YEAR, -1);

c.add(Calendar.MONTH, 1);
System.out.println("After one month: " + formatter.format(c.getTimeInMillis()));
c.add(Calendar.MONTH, -1);

c.add(Calendar.YEAR, 1);
System.out.println("After one year: " + formatter.format(c.getTimeInMillis()));
c.add(Calendar.YEAR, -1);

Output:

After one day: 17/09/2014
After one week: 23/09/2014
After one month: 16/10/2014
After one year: 16/09/2015

Answer 2

With Joda-time :

DateTimeFormatter formatter = DateTimeFormat.forPattern("dd/MM/yyyy");
LocalDate date = LocalDate.parse("16/09/2014", formatter);

System.out.println(date.toString(formatter));
System.out.println(date.plusDays(1).toString(formatter));
System.out.println(date.plusWeeks(1).toString(formatter));
System.out.println(date.plusMonths(1).toString(formatter));
System.out.println(date.plusYears(1).toString(formatter));

Output:

16/09/2014
17/09/2014
23/09/2014
16/10/2014
16/09/2015

Answer 3

Use Calendar api of Java/Android as follow:

SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");

Date date;

try {
    date = sdf.parse(dateStr);
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.DAY_OF_MONTH, 1); //add one day to your date
    cal.add(Calendar.MONTH, 1); //add 1 month to your date 
    cal.add(Calendar.YEAR, 1); //add 1 year to current date
    System.out.println(sdf.format(cal.getTimeInMillis()));
} catch (ParseException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

Answer 4

Here is the example:

String strDate = "16/09/2014";
int noOfDays = 1;
SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
Date date = formatter.parse(strDate);
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.add(Calendar.DATE, noOfDays);

Answer 5

tl;dr

LocalDate.parse( 
    "16/09/2014" , 
    DateTimeFormatter.ofPattern( "dd/MM/uuuu" )
)
.plusDays( 1 )
.format( DateTimeFormatter.ofPattern( "dd/MM/uuuu" ) )

Details

Tip: Use date-time data types for date-time values. You should be using a date-oriented type to define your column in your database to store a date value rather than as text.

Tip # 2: When you do serialize a date value to text, use the standard ISO 8601 formats. These are sensible, practical, and sort chronologically when alphabetical.

Use the java.time classes rather than the troublesome old date-time classes that are now legacy. For Android, see bullets below.

DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd/MM/uuuu" ) ;
LocalDate ld = LocalDate.parse( "16/09/2014" , f ) ;

LocalDate dayAfter = ld.plusDays( 1 ) ; 
LocalDate weekAfter = ld.plusWeeks( 1 ) ;
LocalDate monthAfter = ld.plusMonths( 1 ) ;
LocalDate yearAfter = ld.plusYears( 1 ) ;

To generate a string in standard format, simply call toString .

String output = dayAfter.toString() ;  // YYYY-MM-DD standard format.

2014-09-17

For other formats, use a DateTimeFormatter as seen above.

String output = dayAfter.format( f ) ;  

17/09/2014

---

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date , Calendar , & SimpleDateFormat .

The Joda-Time project, now in maintenance mode , advises migration to the java.time classes.

To learn more, see the Oracle Tutorial . And search Stack Overflow for many examples and explanations. Specification is JSR 310 .

Where to obtain the java.time classes?

• Java SE 8 , Java SE 9 , and later
  • Built-in.
  • Part of the standard Java API with a bundled implementation.
  • Java 9 adds some minor features and fixes.
• Java SE 6 and Java SE 7
  • Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport .
• Android
  • The ThreeTenABP project adapts ThreeTen-Backport (mentioned above) for Android specifically.
  • See How to use ThreeTenABP… .