Unable to convert string to human-readable format

Question

What is wrong with my code here? I'm unable return a String in the format I'd like...

Method Call:

incident.setTargetDate(DateUtil.formatResolutionTime(targetDateList.get(i)));

Formatter:

public class DateUtil {

    public static String formatResolutionTime(String startDateString) {
        DateFormat df = new SimpleDateFormat("MM/dd/yyyy");
        Date startDate = null;

        try {
            startDate = df.parse(startDateString);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        String newDateString = df.format(startDate);
        System.out.println(newDateString);
        return newDateString;    
    }        
}

Exception:

java.text.ParseException: Unparseable date: "2017-05-26T00:00:00+02:00"
    at java.text.DateFormat.parse(DateFormat.java:366)
    at app.util.DateUtil.formatResolutionTime(DateUtil.java:19)
    at app.controller.TableViewController.retrieveTicketsForTable(TableViewController.java:194)
    at app.controller.TableViewController.initialize(TableViewController.java:139)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
    at app.Main.start(Main.java:14)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)

Answer 1

You need two formats. One for parsing the input format and one for formating the Output.

public static String formatResolutionTime(String startDateString) {
    DateFormat dfParse = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZZZZ"); //Format for parsing the Input string
    DateFormat df = new SimpleDateFormat("MM/dd/yyyy"); //Format for formatting the output
    Date startDate = null;

    try {
        startDate = dfParse.parse(startDateString);
    } catch (ParseException e) {
        e.printStackTrace();
    }
    String newDateString = df.format(startDate);
    System.out.println(newDateString);
    return newDateString;

}

Answer 2

You are getting the exception Unparseable date: "2017-05-26T00:00:00+02:00" , because you are trying to parse a String of the format "yyyy-MM-dd'T'hh:mm:ssXXX" , but telling the formatter that your string is of type MM/dd/yyyy. Your input String is of the format "2017-05-26T00:00:00+02:00" and you want the output in the format MM/dd/yyyy , so as suggested in other posts, you need two formatters.

public static String formatResolutionTime(String startDateString) {

        DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ssXXX");
        Date startDate = null;

        try {
            startDate = df.parse(startDateString);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        DateFormat newFormatter = new SimpleDateFormat("MM/dd/yyyy");
        String newDateString = newFormatter.format(startDate);
        System.out.println(newDateString);
        return newDateString;

    }

Answer 3

您正在检查格式为MM / DD / YYYY的日期，但提供的日期为YYYY-MM-DD格式。

Answer 4

You have to use two DateFormat objects: one for parsing (input -> date) and one for formatting (date -> output).

Your input is 2017-05-26T00:00:00+02:00 . Let's break it down (refer SimpleDateFormat ):

• 2017 : the year in the format yyyy
• 05 : the month in the format MM
• 26 : the day in the format dd
• T : separator between date and time in the format of character 'T'
• 00 : the hour in the format HH ( not hh )
• 00 : the minutes in the format mm
• 00 : the seconds in the format ss
• +02:00 : the time zone in the format XXX

So your SimpleDateFormat parser pattern will be

yyyy-MM-dd'T'HH:mm:ss:XXX

Additional notes

In case of ParseException your code could result in unexpected behaviour, in fact after the try/catch block your startDate will be null and the formatter will try to format the null date and return the result, generating a NullPointerException .

Said that, my code would be:

private static final String PARSE_PATTERN = "yyyy-MM-dd'T'HH:mm:ssXXX";
private static final String FORMAT_PATTERN = "MM/dd/yyyy";
// we cannot declare the SimpleDateFormat as static since it isn't thread-safe

public static String formatResolutionTime(String startDateString) {

    try {
        DateFormat parser = new SimpleDateFormat(PARSE_PATTERN);
        Date startDate = parser.parse(startDateString);

        DateFormat formatter = new SimpleDateFormat(FORMAT_PATTERN);
        return formatter.format(startDate);
    } catch (ParseException e) {
        // e.printStackTrace();
        return "Error"; // or whatever, but return a string here
    }
}

Answer 5

This thread of answers would not be complete without the modern answer.

    DateTimeFormatter dtf = DateTimeFormatter.ofPattern("MM/dd/yyyy");
    String newDateString = OffsetDateTime.parse(startDateString).format(dtf);

The result is

05/26/2017

The answers I have read until now are correct — and outdated. In 2017 it's time to skip the old classes SimpleDateFormat and Date , and use the newer Java date and time API , in this case DateTimeFormatter and OffsetDateTime . This is even more appropriate as your original date-time string conforms with ISO 8601, the format that the newer classes “understand” as their default. So we need not give an explicit format for parsing (as would be needed with SimpleDateFormat ).

Answer 6

    DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
    Date date = new Date();
    //System.out.println(dateFormat.format(date));
    return dateFormat.format(date);

It works for me)