Re: Date and null

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 21 Apr 2008 23:59:23 -0400
Message-ID:
<CMqdnVQ0qq4G_5DVnZ2dnUVZ_h-vnZ2d@comcast.com>
teser3@hotmail.com wrote:

I have a Date variable in a JavaBean that works with a Oracle
Database.
If there is a Date value in the database it shows in the JSP with no
problems.
But if there is no value in the Date value it gives me a null error in
the JSP.
How do I account for null with a Date object?


Test the reference for "== null".

If there is not Date value I still want the page to show the Date
Title with nothing there.
For example:
JSP view example if there is a Date value:
Submit Date: June 25, 2007

JSP view example if there is not a Date value should show like this
but it doesnt show and gives me a null error:
Submit Date:


Well, what do you expect when you attempt to format a null value?

My classes and JSP:

Bean:

   private Date subDate;

    public String getSubDate(){
        SimpleDateFormat formatter = new SimpleDateFormat ("MMMM dd,
yyyy");


You could set 'formatter' as a static final variable, since you never change it.

        return formatter.format(this.subDate);
    }

    /*
   Also tried this just to put a value in there if null but it didnt
work:
       public String getSubDate(){
        if((subDate == null)


This won't even compile. Are you sure this is what your code was?

        {
             subDate = null;


OK, having ascertained via the 'if' that 'subDate' is null, you then
redundantly set it to null yet again, accomplishing no change.

        }
        SimpleDateFormat formatter = new SimpleDateFormat ("MMMM dd,
yyyy");
        return formatter.format(this.subDate);


It seems that you can't format a null date. Just return "" if 'subDate == null'.

    }

    */

    public void setSubDate(String subDate){
        this.subDate= subDate;
    }

Helper class:

while(rs.next()){
            AddressRowBean row = new AddressRowBean();
            row.setSubDate(rs.getDate("subDate"));
            ...

JSP Bean call:

Submit Date: <jsp:getProperty name="projectObject"
property="subDate" />


If you use Expression Language (EL), it does the right thing with null values.

   Submit Date: <c:out value="${subDate}" />

However, SimpleDateFormat will still blow up on the null reference.

--
Lew

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