how to display the data from database on a button click in java jsf

Question

<f:view>
        <h:form>
            <h:panelGrid>
                <f:facet name="header">
                    <h:outputText value="Student Mark List"/>
                </f:facet>
                <h:column>
                    <h:outputText value="Student Number : "></h:outputText>
                    <h:inputText value="#{stuBean.stuNumber}"/>
                </h:column>
                <h:column>
                    <h:commandButton id = "getStuMarkList" value="Get Mark List" action="#{stuBean.listOfMarks}" >
                    </h:commandButton> </h:column>
            </h:panelGrid>                          
            <h:panelGrid  bgcolor="#9AC8E6" width="100%">
              <h:dataTable id="datatable" value="#{stuBean.marksList}" var="marksList">
                    <h:column>
                        <f:facet name="header">
                            <h:outputText style=""value="Maths Marks" />
                        </f:facet>
                        <h:inputText value="#{marksList.mMarks}" > </h:inputText>
                    </h:column>
                    <h:column>
                        <f:facet name="header">
                            <h:outputText style=""value="English Marks" />
                        </f:facet>
                        <h:inputText value="#{marksList.eMarks}" > </h:inputText>
                    </h:column>
                    <h:column>
                        <f:facet name="header">
                            <h:outputText style=""value="Physics Marks" />
                        </f:facet>
                        <h:inputText value="#{marksList.pMarks}" > </h:inputText>
                    </h:column>
                    <h:column>
                        <f:facet name="header">
                            <h:outputText style=""value="Social Marks" />
                        </f:facet>
                        <h:inputText value="#{marksList.sMarks}" > </h:inputText>
                    </h:column>
                </h:dataTable>
            </h:panelGrid>
        </h:form>
    </f:view>

StudentBean.java

    //... getters and setters

public String listOfMarks(){
    student.marksListFromDb(stuNum);
    return null;
}

private List marksList= new ArrayList();

public List getMarksList() {       
    return marksList;
}

Please check my above code where I'm trying to get the values from database on button click (listOfMarks) and display them in the datatable. Using the above code it is not fetching the data.Kindly help me if I'm wrong doing wrong some where...

Matt Handy · Accepted Answer · 2011-05-11 08:34:27Z

2

Some general things:

An action method in a commandButton should return void or String. The String is used for navigation. If you want to reload the same page return null.

You are mixing the getter method for your markList with an action method.

You should have an action method e.g. fillMarkList() that fills the list, returns a null String and reloads the current page and you should have a getter method getMarkList() that returns the list for the dataTable:

public String fillMarkList() {
   // fill the list:
   student.markListFromDb(stuNum);
   // reload current page:
   return null;
}

public List getMarkList() {
   return markList();
}

Your button then should call fillMarkList() as action method:

<h:commandButton id="getStuMarkList" 
                 value="Get Mark List" 
                 action="#{stuBean.fillMarkList}" />

UPDATE: Just noticed your usage of h:panelGrid. I tried your version and it renders as correct table. But I think correct usage is without columns. You have to define column number as attribute of h:panelGrid and simply put the containing elements inside the grid:

<h:panelGrid columns="3">
   <f:facet name="header">
       <h:outputText value="Student Mark List"/>
   </f:facet>
   <h:outputText value="Student Number : "></h:outputText>
   <h:inputText value="#{stuBean.stuNumber}"/>
   <h:commandButton id = "getStuMarkList" value="Get Mark List" 
                     action="#{stuBean.listOfMarks}" >
   </h:commandButton> </h:column>
</h:panelGrid>

edited May 11, 2011 at 8:34

answered May 11, 2011 at 6:38

Matt Handy

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5 Comments

Mango Over a year ago

I did trying the same Handy..i didn't work and I tried with above code as in my post. Can you suggest me how do i resolve this..

Matt Handy Over a year ago

What does it mean "didn't work"? Debug your project, check if your action method is called (set breakpoint inside action method) and if the list is filled.

Mango Over a year ago

I've edited my code wich i tried prior(also according to ur suggestion)..My action method for commandbutton is never called here..

Matt Handy Over a year ago

Updated my answer. Don't know if this helps but you could check javascript console errors in browser to see if there are any issues.

Mango Over a year ago

Change in the above way didnn't help me..I'm able to print the list size in the console but when fetching it to datatable the problem arises.. also i have placed some input fields in the datatable which are not displayed right from the page load.. can u check if my code for retrieving data for datatable is correct

Thomas · Accepted Answer · 2011-05-11 06:28:51Z

1

Although that "please check my code" doesn't generally work here, one thing I spotted:

public List getMarkList() {
 student.markListFromDb(stuNum);
 return markList;
}

You don't put anything into markList here, do you?

Edit: also note that those are quite equal in terms of execution: #{stuBean.getMarkList} and #{stuBean.markList} since the latter is likely to be translated to StudentBean.getMarkList() by the framework, as will be #{stuBean.getMarkList}.

edited May 11, 2011 at 6:28

answered May 11, 2011 at 6:06

Thomas

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3 Comments

Thomas Over a year ago

You didn't show the code where the markList is filled. From your code it seems you fetch the data and then do nothing with it.

Thomas Over a year ago

I still can't see where you add elements to marksList. Try to debug the load method and see whether marksList contains anything at the end.

Mango Over a year ago

Individually if i debug the list in my database method...it contains data and list is printed on the console.. when i try debugging th whole...the action of commandButton is not being called...here ` action="#{stuBean.listOfMarks}" ` is not called

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