Set a default time zone for f:convertDateTime

Question

I use JSF1.2 and I have a little problem with time zones.

Calendar respects my timezone and save the correct time in the Database. When I show it using a h:outputtext with a f:convertDateTime it shows the wrong date (I think with default time zone).

I can do something like:

<h:outputText value="#{atividade.atividade.dataCriacao.time}">
  <f:convertDateTime pattern="#{msg.formatoDataCalendario2}" timeZone="America/Sao_Paulo" />
</h:outputText>

formatoDataCalendario2 = dd/MM/yyyy, HH:mm in messages.properties.

I can put the time zone in messages too, but I believe it have some configuration that I could use.

Answer 1

JSF date/time converters defaults by specification to UTC timezone. If you want to use a different timezone, then you really need to specify it in the converter yourself. Or, if you have 100% control over the production runtime environment, then since JSF 2.0 you can set its system timezone to the desired timezone and add the following context parameter to web.xml:

<context-param>
    <param-name>javax.faces.DATETIMECONVERTER_DEFAULT_TIMEZONE_IS_SYSTEM_TIMEZONE</param-name>
    <param-value>true</param-value>
</context-param>

This way JSF will use the system's timezone as obtained by TimeZone#getDefault() as converter's default timezone.

Please note that the java.util.Date object by itself also does not store any timezone information. It also always defaults to UTC timezone. Keep this in mind when processing submitted date/times.

See also:

• Daylight saving time and time zone best practices

Answer 2

For displaying date correctly you need to modify only in your web.xml

<context-param>
    <param-name>javax.faces.DATETIMECONVERTER_DEFAULT_TIMEZONE_IS_SYSTEM_TIMEZONE</param-name>
    <param-value>true</param-value>
</context-param>

and in your xhtml file

<h:outputText value="#{report.date}">
    <f:convertDateTime pattern="dd-MMM-yyyy" />
</h:outputText>

Its a timezone issue. The context param should fix it.