java - Validating a form in JSP -

i'm validating simple form using spring , hibernate in jsp (using simpleformcontroller) of hibernatevalidator explained here. form containing 1 field follows.

<%@page contenttype="text/html" pageencoding="utf-8" %> <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <%@taglib uri="http://www.springframework.org/tags/form" prefix="form" %>  <form:form method="post" id="userform" name="userform" action="temp.htm" commandname="validationform">                <table>         <tr>             <td>user name:<font color="red"><form:errors path="username" /></font></td>         </tr>          <tr>             <td><form:input path="username" /></td>         </tr>                         <tr>             <td><input type="submit" value="submit" /></td>         </tr>         </table>  </form:form> 

the following command class in validation criteria defined.

package validators;  import javax.validation.constraints.size; import org.hibernate.validator.constraints.notempty;   final public class validationform  {     @notempty(message="must not left blank.")     @size(min = 1, max = 2)     private string username;      public void setusername(string username)     {             this.username = username;     }      public string getusername()     {             return username;     }         } 

the following dispatchar-servlet.xml file different configurations can made.

<?xml version="1.0" encoding="utf-8"?> <beans xmlns="http://www.springframework.org/schema/beans"    xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"    xmlns:p="http://www.springframework.org/schema/p"    xmlns:aop="http://www.springframework.org/schema/aop"                  xmlns:mvc="http://www.springframework.org/schema/mvc"    xsi:schemalocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd    http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">     <bean class="org.springframework.web.servlet.mvc.support.controllerclassnamehandlermapping" /> <bean class="org.springframework.web.servlet.mvc.simplecontrollerhandleradapter" />   <bean id="tempservice" class="usebeans.tempserviceimpl" /> <bean id="tempcontroller" class="controller.temp" p:tempservice-ref="tempservice" p:formview="temp" p:successview="temp"/>  <bean id="messagesource" class="org.springframework.context.support.reloadableresourcebundlemessagesource">     <property name="basename" value="/web-inf/messages" /> </bean>  <bean id="urlmapping" class="org.springframework.web.servlet.handler.simpleurlhandlermapping">     <property name="mappings">         <props>             <prop key="index.htm">indexcontroller</prop>             <prop key="temp.htm">tempcontroller</prop>                         </props>     </property> </bean>  <bean id="viewresolver"       class="org.springframework.web.servlet.view.internalresourceviewresolver"       p:prefix="/web-inf/jsp/"       p:suffix=".jsp" />  <bean name="indexcontroller"       class="org.springframework.web.servlet.mvc.parameterizableviewcontroller"       p:viewname="index" /> 

tempservice interface containing 1 method add(validationform validationform){...} , tempserviceimpl class implements tempservice interface.

the controller class temp follows.

package controller;  import java.util.hashmap; import java.util.map; import javax.servlet.http.httpservletrequest; import javax.servlet.http.httpservletresponse; import javax.validation.valid; import org.springframework.validation.bindexception; import org.springframework.web.bind.annotation.modelattribute; import org.springframework.web.servlet.modelandview; import org.springframework.web.servlet.mvc.simpleformcontroller; import usebeans.tempservice; import validators.validationform;  @suppresswarnings("deprecation") final public class temp extends simpleformcontroller {     private tempservice tempservice=null;     public temp()     {                     setcommandclass(validationform.class);         setcommandname("validationform");     }      //this method may not necessary.     public void settempservice(tempservice tempservice)      {         this.tempservice = tempservice;     }      @override     protected modelandview onsubmit(httpservletrequest request, httpservletresponse response, @modelattribute("validationform") @valid object command, bindexception errors) throws exception     {         validationform validationform=(validationform) command;         tempservice.add(validationform);   //may not necessary.                  if(errors.haserrors())  //never evaluates true though text box on form left blank.         {                             system.out.println("user name : "+validationform.getusername());             //or something.         }             else         {             //do stuff such database operations insert, update or delete.          }                   modelandview mv=new modelandview("temp", "validationform", validationform);         return mv;     }      @override     protected modelandview showform(httpservletrequest request, httpservletresponse response, bindexception errors) throws exception     {                     modelandview mv=new modelandview("temp", "validationform", new validationform());         return mv;     } } 

now, happening here when form submitted on clicking submit button on form, onsubmit() method in controller class temp invoked in i'm imposing if condition if(errors.haserrors()){}.

accordingly, if textfield on form empty, form rendering contains validation errors , if condition should evaluated true , specified error message should displayed (as specified in validationform class @notempty(message="must not left blank.")) never happens [the object of validationform available through object command parameter of onsubmit() method]. condition never evaluates true whether or not text box contains value.

what missing here? feel i'm following wrong way use hibernatevalidator. hints or guidelines helpful me.

[the application runs no errors form intended validated isn't validated]

putting @valid on method params doesn't work old-fashioned controllers extend commandcontroller , children (e.g., simpleformcontroller). feature of annotationmethodhandleradapter, need using annotated controller work.

(there reason had suppress deprecation warning on class! :) )

reader's digest version:

instead of defining own urlmapping , in dispatcher use <mvc:annotation-driven/>

then instead of extending simpleformcontroller make regular class , annotate @controller , method @requestmapping.

@controller @requestmapping("/temp.htm") public class temp {  @requestmapping(method=requestmethod.get) public modelandview getform() {   modelandview mv=new modelandview("temp", "validationform", new validationform());   return mv; }  @requestmapping(method=requestmethod.post) public modelandview postform(@valid validationform validationform, bindingresult errors) {         tempservice.add(validationform);   //may not necessary.                  if(errors.haserrors())  //never evaluates true though text box on form left blank.         {                             system.out.println("user name : "+validationform.getusername());             //or something.         }             else         {             //do stuff such database operations insert, update or delete.          }                   modelandview mv=new modelandview("temp", "validationform", validationform);         return mv; } 

there tons of tutorials on internet way more content can reproduce here. check out current version of spring petclinic sample application detailed examples.