如何计算java中两个日期之间的年龄或差异

Question

I want to get the number of months between 2 dates.The dates are someones birthday and the current date.So im getting the number of years in between the two dates but not the number of months..

Suppose my dates are 06/09/2011 and 06/11/2012 .So i want the answer to be 1yr 2mths .I am getting the year but not the month.Please help.Below is the code for getting the number of years

 public int getAge(Date dateOfBirth)      {                                                                                                                                                                         

    today = Calendar.getInstance(); 
    Calendar birthDate = Calendar.getInstance();

    birthDate.setTime(dateOfBirth);
    if (birthDate.after(today)) {
        throw new IllegalArgumentException("Can't be born in the future");
    }

    age = today.get(Calendar.YEAR) - birthDate.get(Calendar.YEAR);
    month = today.get(Calendar.MONTH) - birthDate.get(Calendar.MONTH);

    if ( (birthDate.get(Calendar.DAY_OF_YEAR) - today.get(Calendar.DAY_OF_YEAR) > 3) ||
            (birthDate.get(Calendar.MONTH) > today.get(Calendar.MONTH ))){
        days = birthDate.get(Calendar.DAY_OF_MONTH) - today.get(Calendar.DAY_OF_MONTH);
        age--;

        Toast.makeText(getApplicationContext(), "inside if", Toast.LENGTH_SHORT).show();
        Log.e("month is",month+"");
        Log.e("Days",days+ " left");


    }else if ((birthDate.get(Calendar.MONTH) == today.get(Calendar.MONTH )) &&
              (birthDate.get(Calendar.DAY_OF_MONTH) > today.get(Calendar.DAY_OF_MONTH ))){
        Toast.makeText(getApplicationContext(), "inside else if", Toast.LENGTH_SHORT).show();

        age--;
    }

    return age;

Answer 1

I have recently created a demo and uploaded here .

It is using JodaTime library for efficient results.

I hope it will be useful.

Screenshot:

Code:

MainActivity.java

public class MainActivity extends Activity {

    private SimpleDateFormat mSimpleDateFormat;
    private PeriodFormatter mPeriodFormat;

    private Date startDate;
    private Date endDate;
    private Date birthDate;


    private TextView tvStartDate,tvEndDate,tvDifferenceStandard,tvDifferenceCustom,tvBirthDate,tvAgeStandard,tvAgeCustom;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        init();

        //determine dateDiff
        Period dateDiff = calcDiff(startDate,endDate);
        tvDifferenceStandard.setText(PeriodFormat.wordBased().print(dateDiff));
        tvDifferenceCustom.setText( mPeriodFormat.print(dateDiff));


        //determine age
        Period age = calcDiff(birthDate,new Date());
        tvAgeStandard.setText(PeriodFormat.wordBased().print(age));
        tvAgeCustom.setText( mPeriodFormat.print(age));

    }

    private void init() {

        //ui
        tvStartDate = (TextView)findViewById(R.id.tvStartDate);
        tvEndDate = (TextView)findViewById(R.id.tvEndDate);
        tvDifferenceStandard = (TextView)findViewById(R.id.tvDifferenceStandard);
        tvDifferenceCustom = (TextView)findViewById(R.id.tvDifferenceCustom);
        tvBirthDate = (TextView)findViewById(R.id.tvBirthDate);
        tvAgeStandard = (TextView)findViewById(R.id.tvAgeStandard);
        tvAgeCustom = (TextView)findViewById(R.id.tvAgeCustom);



        //components
        mSimpleDateFormat = new SimpleDateFormat("dd/MM/yy");
        mPeriodFormat = new PeriodFormatterBuilder().appendYears().appendSuffix(" year(s) ").appendMonths().appendSuffix(" month(s) ").appendDays().appendSuffix(" day(s) ").printZeroNever().toFormatter();


        try {
            startDate = mSimpleDateFormat.parse(tvStartDate.getText().toString());
            endDate =  mSimpleDateFormat.parse(tvEndDate.getText().toString());
            birthDate = mSimpleDateFormat.parse(tvBirthDate.getText().toString());

        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    private Period calcDiff(Date startDate,Date endDate)
    {
        DateTime START_DT = (startDate==null)?null:new DateTime(startDate);
        DateTime END_DT = (endDate==null)?null:new DateTime(endDate);

        Period period = new Period(START_DT, END_DT);

        return period;

    }

}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >


<TextView 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Date Diff Calculator"
    android:textStyle="bold"
    android:gravity="center"
    android:background="@android:color/darker_gray"
    />


<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textStyle="bold"
    android:text="Start Date:" />

<TextView
    android:id="@+id/tvStartDate"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="06/09/2011" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textStyle="bold"
    android:text="End Date:" />

<TextView
    android:id="@+id/tvEndDate"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="29/10/2013" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textStyle="bold"
    android:text="Difference (Standard)" />

<TextView
    android:id="@+id/tvDifferenceStandard"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="result" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textStyle="bold"
    android:text="Difference (Custom)" />

<TextView
    android:id="@+id/tvDifferenceCustom"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="result" />


<TextView 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Age Calculator"
    android:textStyle="bold"
    android:gravity="center"
    android:background="@android:color/darker_gray"
    />

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textStyle="bold"
    android:text="Birth Date:" />

<TextView
    android:id="@+id/tvBirthDate"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="01/09/1989" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textStyle="bold"
    android:text="Age (Standard)" />

<TextView
    android:id="@+id/tvAgeStandard"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="result" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textStyle="bold"
    android:text="Age (Custom)" />

<TextView
    android:id="@+id/tvAgeCustom"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="result" />

Note:

1) don't forget to add JodaTime library to your project

2) As you can see in layout file, I have used fixed value for "Start Date","End Date" to calculate Date Difference and fixed value for "Birth Date" to calculate Age . You may replace it with your dynamic values .

Answer 2

Joda Time has code to do all this and more

You can do the following to get the month between two dates:

Calendar startCalendar = new GregorianCalendar();
startCalendar.setTime(startDate);
Calendar endCalendar = new GregorianCalendar();
endCalendar.setTime(endDate);

int diffYear = endCalendar.get(Calendar.YEAR) - startCalendar.get(Calendar.YEAR);
int diffMonth = diffYear * 12 + endCalendar.get(Calendar.MONTH) - startCalendar.get(Calendar.MONTH);

Check out Link

Note: that if your dates are 2013-01-31 and 2013-02-01 , you get a distance of 1 month this way, which may or may not be what you want.

Answer 3

java.time

Because this answer got referenced from here …

With java.time classes you can calculate the age very easy:

long years = ChronoUnit.YEARS.between(LocalDate.of(1900, Month.NOVEMBER, 20), LocalDate.now());

or (if you need year and months)

Period p = Period.between(birthday, today);
p.getYears();
p.getMonths();

To count all the months in the entire period, as asked in the Question, call toTotalMonths .

int totalMonths = p.toTotalMonths();

Answer 4

Age can be calculate in a very easy way. The following is my complete java code .

 public class age {


    public static void main(String [] args){
        Scanner s=new Scanner(System.in);
        Date dd=new Date();
        int d=Integer.parseInt(new SimpleDateFormat("dd").format(dd));
        int m=Integer.parseInt(new SimpleDateFormat("MM").format(dd));
        int y=Integer.parseInt(new SimpleDateFormat("yyyy").format(dd));
         System.out.println( "Enter Day ");
        int d1=Integer.parseInt(s.nextLine());
        System.out.println( "Enter Month ");
        int m1=Integer.parseInt(s.nextLine());
         System.out.println( "Year");
        int y1=Integer.parseInt(s.nextLine());
        if(d<d1){
            d+=30;
            m-=1;
        }
        if(m<m1){
            m+=12;
            y-=1;
        }
      System.out.println((y-y1)+" years "+(m-m1)+"  month "+(d-d1)+" days ");

    }
 }