JSTL: formatDate Vs Timestamp

[Celso Oliveira]

Hi everyone.
It�s my first post here.
I�m having some trouble and I don�t know what to do.

I have a JavaBean, User, with the following attribute: private Timestamp birthDate;

I�m trying to use the <c:set> tag to set this attribute when I load a JSP page.

here�s what I�m doing:

<jsp:useBean id="objUsr" class="user.entity.User" scope="session">
    <jsp:setProperty name="objUsr" property="*"/>
    <c:set target="${objUsr}" property="birthDate" value="<fmt:parseDate value='${param.bDate}' type='date' dateStyle='short' pattern='dd/MM/yyyy'/>"/>
</jsp:useBean>

And here�s the error I get:

javax.servlet.jsp.el.ELException: Attempt to convert String "<fmt:parseDate value='06/09/2006' type='date' dateStyle='short' pattern='dd/MM/yyyy'/>" to type "java.sql.Timestamp", but there is no PropertyEditor for that type    

Do I have to build my own custom-tag to deal with java.sql.Timestamp ??

[Christophe Verré]

I've never tried, but I'm wondering if you could do the following:
1. Create a PropertyEditor for Timestamp. Use PropertyEditorSupport and override setAsText(String text). Make sure that the format of the text parameter is the same as the one you've got with fmt:parseDate
2. At the server startup (use a listener), register your PropertyEditor using the PropertyEditorManager.registerEditor(Class targetType, Class editorClass)
3. Try again

This sounds fun to do I may try.

[Bear Bibeault]

<c:set target="${objUsr}" property="birthDate" value="<fmt:parseDate value='${param.bDate}' type='date' dateStyle='short' pattern='dd/MM/yyyy'/>"/>

You cannot use an action as the attribute value of another action.

[Christophe Verré]

Here it is. This has been fun. I'll leave you tweak the date format.
Maybe you should avoid using Timestamp after all

The PropertyEditor

package editors;
 
import java.sql.*;
import java.beans.*;
 
public class TimestampEditor extends PropertyEditorSupport {

Timestamp time;

public Object getValue() 
{
return time;
}

public void setAsText(String text) {
time = Timestamp.valueOf(text);
System.out.println( "Setting timestamp to " + time );
}

}

The ContextListener

package listeners;
 
import javax.servlet.*;
import java.beans.*;
 
public class MainContextListener implements ServletContextListener {

public void contextDestroyed(ServletContextEvent sce) {

}
 
public void contextInitialized(ServletContextEvent sce) {
try {
PropertyEditorManager.registerEditor( Class.forName("java.sql.Timestamp"), Class.forName("editors.TimestampEditor"));
System.out.println("Registered TimestampEditor");
} catch ( ClassNotFoundException e ) {
e.printStackTrace();
}
}
}

The user bean

package servlet;
 
import java.sql.*;
 
public class User {
private String userName;
private Timestamp birthDate;
  
public User() {
}
 
public String getUserName() {
return userName;
}
 
public void setUserName(String puserName){
userName=puserName;
}
 
public Timestamp getBirthDate() {
return birthDate;
}

public void setBirthDate( Timestamp date ) {
birthDate = date;
}

}

Listener registration in web.xml

<listener>
<description>The main contextListener</description>
<listener-class>listeners.MainContextListener</listener-class>
</listener>

The JSP test file

<jsp:useBean id="userbean" class="servlet.User">
<jsp:setProperty name="userbean" property="userName" value="satou"/>
<jsp:setProperty name="userbean" property="birthDate" value="1980-01-01 15:30:00.000000000"/>
</jsp:useBean>
 
My name is ${userbean.userName}.
I was born on ${userbean.birthDate}.

[Bear Bibeault]

Ummmmmm, well, I guess Rube Goldberg would be proud?

You could just move the <fmt> action to the body of the <c:set>:

<c:set target="${objUsr}" property="birthDate">
  <fmt:parseDate value='${param.bDate}' type='date' dateStyle='short' pattern='dd/MM/yyyy'/>
</c:set>

[ September 06, 2006: Message edited by: Bear Bibeault ]

[Christophe Verré]

I guess Rube Goldberg would be proud?

I actually wanted to try the PropertyEditor, which I've never used.
Spring is using the same kind of stuff to register custom property editors to set beans' properties.

(But your one liner broke my heart ;) )

[Bear Bibeault]

Didn't mean to break your heart , but why over-complicate matters when a simple answer will suffice?
[ September 06, 2006: Message edited by: Bear Bibeault ]

[Christophe Verré]

By the way, are you sure this works with Timestamp ?
I've tried with

<fmt:parseDate var="birthDate" value='01/01/1980' type='date' dateStyle='short' pattern='dd/MM/yyyy'/>
<jsp:setProperty name="userbean" property="birthDate" value="${birthDate}"/>

but got an exception : cannot convert java.util.Date into java.sql.Timestamp.

[Stefan Evans]

No, JSTL can't convert a java.util.Date into a java.sql.Timestamp automatically.

There are a couple of approaches I can think of:
1 - Add a setter for the property that takes a java.util.Date, and converts it to a timestamp internally.
ie

public void setBirthDate(java.util.Date when){
  setBirthDate(new java.sql.Timestamp(when.getTime()));
}

2 - in the bean use java.util.Date rather than java.sql.Timestamp to declare the property. Convert it to a java.sql.Timestamp (if necessary) in the JDBC code. That separates the Bean from your data access layer.

Hope this helps,
evnafets

[Celso Oliveira]

Hi people.
Thanks everyone for the sugestions.

It�s strange...
When I try to show(get) a Timestamp attribute with JSTL it�s OK. No erros.

    
<input name="bDate" type="text"
value="<fmt:formatDate value="${objUsr.birthDate}" type="date" dateStyle="short" pattern="dd/MM/yyyy"/>"
size="10" maxlength="10">

When I try to set....All my problems start....

I�ll try somethings....

Thank you all again!!!

[Stefan Evans]

Its because java.sql.Timestamp extends java.util.Date

So you can use a Timestamp object anywhere you use a Date (thus your display code works)
However anywhere that specifes timestamp (such as your save code) will not accept just plain Date objects - only Timestamps.

[Celso Oliveira]

Thanks Satou

Your sugestion worked FINE!!!

I had to make a few adjustments but it was OK!!!

Thank you very much!!!