Convert Date String into Epoch in Java [duplicate]

问题:

This question already has an answer here:

• Convert a date format in epoch 5 answers

Is there a way to convert a given Date String into Milliseconds (Epoch Long format) in java? Example : I want to convert

public static final String date = "04/28/2016"; 

into milliseconds (epoch).

回答1:

Date.getTime() Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object.

回答2:

You can simply parse it to java.util.Date using java.text.SimpleDateFormat and call it's getTime() function. It will return the number of milliseconds since Jan 01 1970.

public static final String strDate = "04/28/2016";
try {
    Long millis = new SimpleDateFormat("MM/dd/yyyy").parse(strDate).getTime();
} catch (ParseException e) {
    e.printStackTrace();
}

回答3:

You can create a Calendar object and then set it's date to the date you want and then call its getTimeInMillis() method.

Calendar c = new Calendar.getInstance();
c.set(2016, 3, 28);
c.getTimeInMillis();

If you want to convert the String directly into the date you can try this:

String date = "4/28/2016";
String[] dateSplit = date.split("/");
c.set(Integer.valueOf(dateSplit[2]), Integer.valueOf(dateSplit[0]) - 1, Integer.valueOf(dateSplit[1]));
c.getTimeInMillis();

回答4:

You will need to use Calendar instance for getting millisecond from epoch

try {
    SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy");
    java.util.Date d = sdf.parse("04/28/2016");
    /*
     * Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object.
     */
    System.out.println(d.getTime());
    //OR
    Calendar cal = Calendar.getInstance();
    cal.set(2016, 3, 28);
    //the current time as UTC milliseconds from the epoch.
    System.out.println(cal.getTimeInMillis());
} catch (ParseException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}