How to validate a field in jsf

问题

I have many fields in my addNew.xhtml page. I have to do validations of the fields on client side. One of the field is city.

I want to get a validation error if I don't enter city which says city cannot be left blank.

Previously I was working on grails framework and it was a very easy task to customize validations. Now I am working on jsf and I'm having trouble finding good examples on the internet to solve this issue.

Can you please help me out in implementing this validation

   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:a4j="http://richfaces.org/a4j">
   <head>
       <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
     <link type="text/css" rel="stylesheet" href="../css/global.css" />

   </head>
       <body>
<div class="windowContents">
    <a4j:form style="width: 700px; height: 500px" ajaxSubmit="true"
        id="addNewRecord">

            <a4j:repeat value="#{addAction.editedtable}"
                var="address">

                <br />
                <br />

                    <table border="0" style="font-size: 12px; width: 100%;">
                        <tr>
                            <td><h:outputText value="File ID:" /></td>
                            <td><h:outputText value="#{address.fileId}" /></td>

                            <td><h:outputText value="Insured Name" />:</td>
                            <td><h:outputText value="#{dataEntryAction.insuredName}" /></td>
                        </tr>
                        <tr>
                            <td><h:outputText value="House No" /><span class="red">*</span>:</td>
                            <td><h:inputText value="#{address.houseNumber}" /></td>

                            <td><h:outputText value="Street" /><span class="red">*</span>:</td>
                            <td><h:inputText value="#{address.street}" /></td>
                        </tr>
                        <tr>
                            <td><h:outputText value="City" />:</td>
                            <td><h:inputText id ="city" value="#{address.city}" required="false" requiredMessage="City is required" /></td>
                                            <h:message for="city" />


                        </tr>

                    </table>
            </a4j:repeat>
            <br />
            <h:panelGroup rendered="true">
                <a4j:commandButton value="save" image="../images/buttons/save.gif"
                      render="@form"
                    action="#{addAction.saveEditedAndPrepareHistory(addAction.userComment,user, addAction.editedtable)}"
                    reRender="dataEnrtyTable,dataEntryDetails"
                    oncomplete="javascript:Richfaces.hideModalPanel('addNewRecordPanel')"
                    style="align:center;" />

            </h:panelGroup>


    </a4j:form>
</div>

回答1:

There are different options in JSF for achieving your task,

1. Client side validations.

You asked in your question regarding client side validation.

<tr>
   <td><h:outputText value="City" />:</td>
    <td><h:inputText value="#{address.city}" id="cityID"/></td>
</tr>

<h:commandLink action="#{yourBean.submitMethod}" onclick="checkCity(cityID)"> 
    <h:outputText value="Submit"></h:outputText>
</h:commandLink>

function checkCity(cityID)
{
    var cityEntered = $("#" + cityID).val();
    //Do whatever validations you want
}

Not related to your question There are other ways also (which you have not asked in your question).

2. maxlength - The maximum number of characters that may be entered in this field.

<h:inputText id="cityID" value="#{yourBean.cityID}" maxlength="10"/>

3. Server side validations

Lets say you have not put onclick event for h:commandLink in point. 1

In your Facelets page,

<h:messages globalOnly="true" layout="table" />


public String submitMethod() {
 try
 {
    FacesContext facesContext = null;
    facesContext=FacesContext.getCurrentInstance();

    ArrayList <String> errorList= new ArrayList <String>();
    if(this.cityID.equals(//something))
     {
       errorList.add("//some message");
     }
     if(errorList != null && errorList.size() > 0)
     {
        for(int i=0;i<errorList.size();i++)
         {
           msg= (String)errorList.get(i);
           FacesMessage facemsg= new FacesMessage(FacesMessage.SEVERITY_ERROR,msg ,msg);
           facesContext.addMessage(null, facemsg);
         }
     }
 }
 catch(Exception e)
  {
    //Do error handling
  }

}

4. Built in validator components

<h:inputText id="cityID" value="#{yourBean.cityID}">
    <f:validateLength minimum="6" maximum="15"/>
</h:inputText>

回答2:

Strictly answering your question, in JSF 1.2+, this should do it:

<h:outputLabel for="city" value="City" />
<h:inputText id="city" value="#{address.city}" required="true" requiredMessage="City cannot be left blank." />
<h:message for="city" />

I think that these articles may be interesting to you:

Validator for multiple fields
JSF conversion and validation

I hope it helps!

来源：https://stackoverflow.com/questions/15515946/how-to-validate-a-field-in-jsf

标签

validation

jsf

jsf-1.2