How to convert String to java.util.date so as to make it insertable to the mysql database column of type "DATE"?

Question

The user inputs a date as a string, but I need to make that insertable to the database column of datatype DATE. This is how I've defined my startDate variable in my Event.java class:

@Column(name = "start_date")
@Temporal(javax.persistence.TemporalType.DATE)
private Date startDate;

Note: The Date datatype is from the class java.util.Date

The user inputs the date like this:

I fetch that data as a string value with the following bit of code in my controller:

@RequestMapping(value = "/addEvent", method = RequestMethod.POST)
    public String addEvent(
            //OTHER PARAMETERS
            @RequestParam("startDate") String startDate,
            //OTHER PARAMETERS
                              ) {

        //CODE TO MAP EVENT DATA TO THE ENTITY CLASS
        eventDAO.insert(event);
        return "redirect:/";
    }

The above code successfully inserts an event to the database but leaves the start_date column NULL. How do I parse the string value to a date datatype so as to be insertable into the MySQL DB?

EDIT:

I tried adding the following to parse it but it still inserts NULL.

        Date finalStartDate=null;
        String startDateParser = startDate;
        DateFormat format = new SimpleDateFormat("MM/dd/yyyy");
        try{
        finalStartDate = format.parse(startDateParser);
        System.out.println(finalStartDate);
        } catch(ParseException ex){
            System.out.println(ex.getMessage());
        }

        Event event = new Event();
        //MAPPING OTHER DATA
        event.setStartDate(finalStartDate);

I got this message in my server:

Unparseable date: "2018-04-19"

Use either DateFormat or, better yet, the new java.time package. — duffymo, Apr 19 '18 at 14:58
Either a Google or SO search will turn up more examples than you can shake a stick at. You can't be a developer without using the internet to find such resources. — duffymo, Apr 19 '18 at 15:01
Please check this question on SO: https://stackoverflow.com/questions/4216745/java-string-to-date-conversion — gil.fernandes, Apr 19 '18 at 15:03
@turing042 have you check event object in your controller method?First need to find out if the `startDate` have value — flyingfox, Apr 19 '18 at 15:12
@gil.fernandes thanks for the link, I tried that but got some error, so I've added a few more lines to my original post accordingly. — turing042, Apr 19 '18 at 15:17
I recommend you avoid the `SimpleDateFormat` class. It is not only long outdated, it is also notoriously troublesome. Today we have so much better in [`java.time`, the modern Java date and time API](https://docs.oracle.com/javase/tutorial/datetime/). — Ole V.V., Apr 21 '18 at 05:21
@OleV.V. Thanks for the suggestion, I'll definitely check it out. — turing042, Apr 21 '18 at 06:01

score 0 · Accepted Answer · answered Apr 19 '18 at 15:21

The specific error in this case is the wrong date format. Instead of MM/dd/yyyy you should use yyyy-MM-dd in order to parse the date.

If the date cannot be parsed null is inserted in the database and that is ok. This means that the format of the date is wrong.

Here is a snippet of code which should work be able to parse the date:

String startDateParser = "2018-04-19";
DateFormat format = new SimpleDateFormat("yyyy-MM-dd");
Date finalStartDate = null;
try {
    finalStartDate = format.parse(startDateParser);
    System.out.println(finalStartDate);
} catch (ParseException ex) {
    System.out.println(ex.getMessage());
}

The format used to input the date in the browser and internal processing is different I suppose. Anyway, this worked, thanks Gil! — turing042, Apr 19 '18 at 15:26

How to convert String to java.util.date so as to make it insertable to the mysql database column of type "DATE"?

1 Answers1