I want to calculate the age from a date of birth in Date format. I've tried with this code that seems to work fine, but is it the most convenient way?
LocalDate hoy = LocalDate.now();
LocalDate nacimiento = usuarioActivo.getFechaNacimiento().toInstant().
atZone(ZoneId.systemDefault()).toLocalDate();
long edad = ChronoUnit.YEARS.between(nacimiento, hoy);
The Java 8 API for Dates and Hours is tremendous. I use it and it is my favorite. You can use JODA as it says to you @Alejandro Rangel Celis, which is compatible with previous versions of Java.
The way you have it is valid, but not entirely correct because you do not take into account the months. For this you can use the class Period :
import java.time.LocalDate;
import java.time.Period;
import java.time.format.DateTimeFormatter;
// 01/01/2000
DateTimeFormatter fmt = DateTimeFormatter.ofPattern("dd/MM/yyyy");
LocalDate fechaNac = LocalDate.parse("15/08/1993", fmt);
LocalDate ahora = LocalDate.now();
Period periodo = Period.between(fechaNac, ahora);
System.out.printf("Tu edad es: %s años, %s meses y %s días",
periodo.getYears(), periodo.getMonths(), periodo.getDays());
Exit:
Tu edad es: 22 años, 9 meses y 29 días
Review Joda , simplify dates and time calculations (Joda is also the basis of the new apis / date / date standard) Java time).
Java 8 has something very similar and it's worth reviewing.
Example
LocalDate birthdate = new LocalDate (1970, 1, 20);
LocalDate now = new LocalDate();
Years age = Years.yearsBetween(birthdate, now);
Here a similar question on the site in English.
To work Dates in Java, it is recommended to use the library JODA . With it you can make this code retro-compatible since LocalDate comes from version 1.8 of Java.
public static String getEdad(Date fechaNacimiento) {
if (fechaNacimiento != null) {
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
StringBuilder result = new StringBuilder();
if (fechaNacimiento != null) {
result.append(sdf.format(fechaNacimiento));
result.append(" (");
Calendar c = new GregorianCalendar();
c.setTime(fechaNacimiento);
result.append(calcularEdad(c));
result.append(" años)");
}
return result.toString();
}
return "";
}
private static int calcularEdad(Calendar fechaNac) {
Calendar today = Calendar.getInstance();
int diffYear = today.get(Calendar.YEAR) - fechaNac.get(Calendar.YEAR);
int diffMonth = today.get(Calendar.MONTH) - fechaNac.get(Calendar.MONTH);
int diffDay = today.get(Calendar.DAY_OF_MONTH) - fechaNac.get(Calendar.DAY_OF_MONTH);
// Si está en ese año pero todavía no los ha cumplido
if (diffMonth < 0 || (diffMonth == 0 && diffDay < 0)) {
diffYear = diffYear - 1;
}
return diffYear;
}
//declarar una fecha de nacimiento
LocalDate fechaNacimiento.of(1982, Month.June, 22);
//crear fecha de hoy para comparar
LocalDate fechaHoy = LocalDate.now();
//ahora comparar los años de las dos fechas y asi obtener la edad
int edad = fechaHoy.getYear() - fechaNacimiento.getYear();