Could you help me please, I have a date eg: Year / month / day 2018/05/05 I need that when I add a button this one adds me a month 2018/06/05 but the day remains the same, I have to put the variable in Date because I'm thinking of taking it to my database phpMyAdmin, Basically that when they undad the button to pay the variable in which I have the date of the last payment, change and move on to the next month
As you mentioned @E. Betanzos, you should use Calendar:
String fechaInicial = "2018/05/05";
SimpleDateFormat formateador = new SimpleDateFormat("yyyy/MM/dd");
Date fecha = parser.parse(fechaInicial);
Calendar calendario = Calendar.getInstance();
calendario.setTime(fecha);
calendario.add(Calendar.MONTH, 1);
String fechaConUnMes = formateador.format(calendario.getTime());
System.out.println("Ahora " + fechaConUnMes);
I have not tested it, but it should work.
I do not recommend the Calendar API at all. JodaTime is a much better implementation, with a much more elegant design. You have very useful methods to work with dates, including plusMonths that what you do, as you can see by name, is adding n months to your date object. I show you examples:
The first is the case that you raise, I have 2018/05/05 and I must obtain 2018/06/05. In the second case I have 2016/01/29 (leap year) and I must get 2016/02/29
public class FechasTest {
private DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyy/MM/dd");
@Test
public void debeAumentarUnMesALaFecha() {
LocalDate fecha = formatter.parseDateTime("2018/05/05").toLocalDate();
LocalDate fechaEsperada = formatter.parseDateTime("2018/06/05").toLocalDate();
assertThat(fecha.plusMonths(1)).isEqualTo(fechaEsperada);
}
@Test
public void obtengo29DeFebreroPorqueEsUnAnioBisiesto() {
LocalDate fecha = formatter.parseDateTime("2016/01/29").toLocalDate();
LocalDate fechaEsperada = formatter.parseDateTime("2016/02/29").toLocalDate();
assertThat(fecha.plusMonths(1)).isEqualTo(fechaEsperada);
}
}