Question

<h:dataTable id="dt1" value="#{StudentMark.stuList}" var="stuList"  bgcolor="#9AC8E6" border="10" cellpadding="5" cellspacing="3" rows="18" width="120%" dir="LTR" frame="hsides>
                <h:column>
                    <f:facet name="header">
                        <h:outputText style=""value="Student Number" />
                    </f:facet>
                    <h:outputText style="" value="#{stuList.stuNumber}"></h:outputText>
                </h:column>
                <h:column>
                    <f:facet name="header">
                        <h:outputText value="Date"/>
                    </f:facet>
                    <h:outputText value="#{stuList.date}">
                        <f:convertDateTime type="date" pattern="dd-MM-yyyy"/></h:outputText>
                </h:column>
                <h:column>
                    <f:facet name="header">
                        <h:outputText value="Name"/>
                    </f:facet>
                    <h:outputText value="#{stuList.stuName}"></h:outputText>
                </h:column>
                <h:column>
                    <f:facet name="header">
                        <h:outputText value="Division"/>
                    </f:facet>
                    <h:outputText value="#{stuList.division}"></h:outputText>
                </h:column>
                <h:column>
                    <f:facet name="header">
                        <h:outputText value="Annual Marks"/>
                    </f:facet>
                    <h:outputText value="#{stuList.annualMark}"></h:outputText>
                </h:column>                    
                <h:column>
                    <f:facet name="header">
                        <h:outputText value="Student History"/>
                    </f:facet>
                     <h:form>
                        <h:commandButton id = "historyBtn" value="Student History" action="#{stuBean.showHistory}">
                            <f:param name="sNumber" value="#{stuBean.stuNumber}" />
                            <f:param name="sName" value="#{stuBean.stuName}" />
                        </h:commandButton></h:form>                        
                </h:column>
            </h:dataTable>

When i try to get the parameters passed using

        FacesContext context = FacesContext.getCurrentInstance();
        Map requestMap = context.getExternalContext().getRequestParameterMap();
        String studentNum = (String) requestMap.get("sNumber");
        String studentName = (String) requestMap.get("sName");

its showing “null” in studentName and studentNum thereby resulting with a null pointer exception.
Any ideas to resolve this???

Answer 1

I’ve resolved my issue.
The mistake made was I’ve trying to pass the parameters at the page load itself,tried making the param value as value=”#{stuList.stuNumber}” and got the error resolved.

<h:form>
 <h:commandLink id = "historyBtn" value="Student History" action="#{stuBean.showHistory}">
     <f:param name="sNumber" value="#{stuList.stuNumber}" />
     <f:param name="sName" value="#{stuList.stuName}" />
  </h:commandLink></h:form> 

Thanks for all the professionals for their time.