How to convert a full date to a short date in java

问题:

I have a date like this Monday, January 9, 2010

I now want to convert it to

1/9/2010 mm/dd/yyyy

I tried to do this

    var startDate = "Monday, January 9, 2010";
    var convertedStartDate = new Date(startDate);
    var month = convertedStartDate.getMonth() + 1
    var day = convertedStartDate.getDay();
    var year = convertedStartDate.getFullYear();
    var shortStartDate = month + "/" + day + "/" + year;

However it must be thinking the date is in a different format since day returns 1 instead of 9.

回答1:

The getDay() method returns a number to indicate the day in week (0=Sun, 1=Mon, ... 6=Sat). Use getDate() to return a number for the day in month:

var day = convertedStartDate.getDate();

If you like, you can try to add a custom format function to the prototype of the Date object:

Date.prototype.formatMMDDYYYY = function(){
    return (this.getMonth() + 1) + 
    "/" +  this.getDate() +
    "/" +  this.getFullYear();
}

After doing this, you can call formatMMDDYYY() on any instance of the Date object. Of course, this is just a very specific example, and if you really need it, you can write a generic formatting function that would do this based on a formatting string, kinda like java's SimpleDateeFormat (http://java.sun.com/j2se/1.4.2/docs/api/java/text/SimpleDateFormat.html)

(tangent: the Date object always confuses me... getYear() vs getFullYear(), getDate() vs getDay(), getDate() ranges from 1..31, but getMonth() from 0..11

It's a mess, and I always need to take a peek. http://www.w3schools.com/jsref/jsref_obj_date.asp)

回答2:

Here you go:

(new Date()).toLocaleDateString('en-US');

That's it !!

you can use it on any date object

let's say.. you have an object called "currentDate"

var currentDate = new Date(); //use your date here
currentDate.toLocaleDateString('en-US'); // "en-US" gives date in US Format - mm/dd/yy

(or)

If you want it in local format then

currentDate.toLocaleDateString(); // gives date in local Format

回答3:

var d = new Date("Wed Mar 25 2015 05:30:00 GMT+0530 (India Standard Time)"); 
document.getElementById("demo").innerHTML = d.toLocaleDateString();

回答4:

A little late to the party, toLocaleDateString() will remove the leading 0s for the day and month, so we will get something like "1/9/1970", which is not perfect in my opinion. To get a proper format MM/DD/YYYY we can use something like:

new Date(dateString).toLocaleDateString('en-US', {
  day: '2-digit',
  month: '2-digit',
  year: 'numeric',
})

回答5:

date.toLocaleDateString('en-US') works great. Here's some more information on it: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleDateString

回答6:

This is a great place to use Moment.js

JavaScript is notorious for handling dates poorly. There are a few gotchas that you'll be susceptible to if you simply append a date together like this:

var startDate = "Monday, January 9, 2010";
var convertedStartDate = new Date(startDate);
var month = convertedStartDate.getMonth() + 1
var day = convertedStartDate.getDay();
var year = convertedStartDate.getFullYear();
var shortStartDate = month + "/" + day + "/" + year;

• JavaScript implicitly adds a DateTime offset that could push the date into the next day if your user is on the opposite side of the International Date line.
  • i.e. the client is +/- 12 hours or more
• JavaScript will not give you a full 10 characters for the appended case given.
  • i.e. Your service may be expecting "Short Date '01/01/2015'" but if you simply append as in the above case you will end up with '1/1/2015'

You should use Moment.js to handle this case. There are tons of built in formats for dates and you can manually specify them without the risk of the date time offset being added or the format coming out different than what you expect.

For example: moment('01/01/2001').format('L'); Will result in '01/01/2001'

Take a look at this moment.js sandbox on jsfiddle

回答7:

I was able to do that with :

var dateTest = new Date("04/04/2013");
dateTest.toLocaleString().substring(0,dateTest.toLocaleString().indexOf(' '))

the 04/04/2013 is just for testing, replace with your Date Object.

回答8:

You could do this pretty easily with my date-shortcode package:

const dateShortcode = require('date-shortcode')

var startDate = 'Monday, January 9, 2010'
dateShortcode.parse('{M/D/YYYY}', startDate)
//=> '1/9/2010'

回答9:

Try this:

new Date().toLocaleFormat("%x");