Java JSF：编辑dataTable标记中的行

Question

I am trying to update a row in a JSF data table based on the method in this article: http://www.mkyong.com/jsf2/how-to-update-row-in-jsf-datatable/

When I click Save, I am getting this error message:

Conversion Error setting value '1970-09-08' for 'null Converter'.

Screenshot:

Markup:

<h:form>
                        <h:commandButton action="addEmployee" value="Add New" class="btn btn-primary" />
                        <br />

                        <h:dataTable class="table table-striped" value="#{employeeCollection.items}" var="item">
                            <h:column>
                                <f:facet name="header">Edit</f:facet>
                                <h:commandButton action="#{employeeCollection.edit(item)}" value="Edit" class="btn" rendered="#{not item.isEditing}" />
                                <h:commandButton action="#{employeeCollection.save(item)}" value="Save" class="btn btn-success" rendered="#{item.isEditing}" />
                            </h:column>
                            <h:column>
                                <f:facet name="header">First Name</f:facet>
                                <h:inputText value="#{item.firstName}" rendered="#{item.isEditing}" />
                                <h:outputText value="#{item.firstName}" rendered="#{not item.isEditing}" />
                            </h:column>
                            <h:column>
                                <f:facet name="header">Last Name</f:facet>
                                <h:inputText value="#{item.lastName}" rendered="#{item.isEditing}" />
                                <h:outputText value="#{item.lastName}" rendered="#{not item.isEditing}" />
                            </h:column>
                            <h:column>
                                <f:facet name="header">Date of Birth</f:facet>
                                <h:inputText value="#{item.dateOfBirth}" rendered="#{item.isEditing}" />
                                <h:outputText value="#{item.dateOfBirth}" rendered="#{not item.isEditing}" />
                            </h:column>
                        </h:dataTable>
                    </h:form>

I would post the managed bean code, but I don't think that's necessary because when clicking the Save button, the save(item) function never seems to be called anyway... so it must be something else. I am new to Java, so probably I'm forgetting something very basic here, somewhere...

Answer 1

The error describes that there was an error converting the String using a null converter. This happens if you use a Date object in your <h:inputText> tag component without a DateTime converter. You can fix this by changing the JSF code:

<h:column>
    <f:facet name="header">Date of Birth</f:facet>
    <h:inputText value="#{item.dateOfBirth}" rendered="#{item.isEditing}">
        <!-- adding the datetime converter -->
        <f:convertDateTime pattern="yyyy-MM-dd" />
    </h:inputText>
    <h:outputText value="#{item.dateOfBirth}" rendered="#{not item.isEditing}" />
</h:column>

Still, it's not a good approach to handle the date validations for you and your user. It would be better to use a third party library that provides you a Calendar component like PrimeFaces Calendar or RichFaces Calendar .

Note that you can use the JSF provided converters for DateTime and Numbers, and you can create your custom data converters. More info:

• Custom Converter in JSF 2.0
• Custom converter JSF 2 with arguments
• Generic JSF entity converter