Spring MVC form handling annotation example

In this tutorial, we show you how to do form handling by using annotation in Spring MVC web application.

1.

SimpleFormController

vs

@Controller

In XML-based Spring MVC web application, you create a form controller by extending the

SimpleFormController

class.

In annotation-based, you can use

@Controller

instead.

SimpleFormController

public class CustomerController extends SimpleFormController{
//...
}

Annotation

@Controller
@RequestMapping("/customer.htm")
public class CustomerController{
//...
}

2.

formBackingObject()

vs

RequestMethod.GE

T

In

SimpleFormController

, you can initialize the command object for binding in the

formBackingObject()

method. In annotation-based, you can do the same by annotated the method name with

@RequestMapping(method = RequestMethod.GET)

.

SimpleFormController

@Override
protected Object formBackingObject(HttpServletRequest request)
throws Exception {

Customer cust = new Customer();
//Make "Spring MVC" as default checked value
cust.setFavFramework(new String []{"Spring MVC"});

return cust;
}

Annotation

@RequestMapping(method = RequestMethod.GET)
public String initForm(ModelMap model){

Customer cust = new Customer();
//Make "Spring MVC" as default checked value
cust.setFavFramework(new String []{"Spring MVC"});

//command object
model.addAttribute("customer", cust);

//return form view
return "CustomerForm";
}

3.

onSubmit()

vs

RequestMethod.POST

In

SimpleFormController

, the form submission is handle by the

onSubmit()

method. In annotation-based, you can do the same by annotated the method name with

@RequestMapping(method = RequestMethod.POST)

.

SimpleFormController

@Override
protected ModelAndView onSubmit(HttpServletRequest request,
HttpServletResponse response, Object command, BindException errors)
throws Exception {

Customer customer = (Customer)command;
return new ModelAndView("CustomerSuccess");

}

Annotation

@RequestMapping(method = RequestMethod.POST)
public String processSubmit(
@ModelAttribute("customer") Customer customer,
BindingResult result, SessionStatus status) {

//clear the command object from the session
status.setComplete();

//return form success view
return "CustomerSuccess";

}

4.

referenceData()

vs

@ModelAttribute

In

SimpleFormController

, usually you put the reference data in model via

referenceData()

method, so that the form view can access it. In annotation-based, you can do the same by annotated the method name with

@ModelAttribute

.

SimpleFormController

@Override
protected Map referenceData(HttpServletRequest request) throws Exception {

Map referenceData = new HashMap();

//Data referencing for web framework checkboxes
List<String> webFrameworkList = new ArrayList<String>();
webFrameworkList.add("Spring MVC");
webFrameworkList.add("Struts 1");
webFrameworkList.add("Struts 2");
webFrameworkList.add("JSF");
webFrameworkList.add("Apache Wicket");
referenceData.put("webFrameworkList", webFrameworkList);

return referenceData;
}

Spring’s form

<form:checkboxes items="${webFrameworkList}" path="favFramework" />

Annotation

@ModelAttribute("webFrameworkList")
public List<String> populateWebFrameworkList() {

//Data referencing for web framework checkboxes
List<String> webFrameworkList = new ArrayList<String>();
webFrameworkList.add("Spring MVC");
webFrameworkList.add("Struts 1");
webFrameworkList.add("Struts 2");
webFrameworkList.add("JSF");
webFrameworkList.add("Apache Wicket");

return webFrameworkList;
}

Spring’s form

<form:checkboxes items="${webFrameworkList}" path="favFramework" />

5.

initBinder()

vs

@InitBinder

In

SimpleFormController

, you define the binding or register the custom property editor via

initBinder()

method. In annotation-based, you can do the same by annotated the method name with

@InitBinder

.

SimpleFormController

protected void initBinder(HttpServletRequest request,
ServletRequestDataBinder binder) throws Exception {

SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));
}

Annotation

@InitBinder
public void initBinder(WebDataBinder binder) {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");

binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));
}

From Validation

In

SimpleFormController

, you have to register and map the validator class to the controller class via XML bean configuration file, and the validation checking and work flows will be executed automatically.

In annotation-based, you have to explicitly execute the validator and define the validation flow in the

@Controller

class manually. See the different :

SimpleFormController

<bean class="com.mkyong.customer.controller.CustomerController">
<property name="formView" value="CustomerForm" />
<property name="successView" value="CustomerSuccess" />

<!-- Map a validator -->
<property name="validator">
<bean class="com.mkyong.customer.validator.CustomerValidator" />
</property>
</bean>

Annotation

@Controller
@RequestMapping("/customer.htm")
public class CustomerController{

CustomerValidator customerValidator;

@Autowired
public CustomerController(CustomerValidator customerValidator){
this.customerValidator = customerValidator;
}

@RequestMapping(method = RequestMethod.POST)
public String processSubmit(
@ModelAttribute("customer") Customer customer,
BindingResult result, SessionStatus status) {

customerValidator.validate(customer, result);

if (result.hasErrors()) {
//if validator failed
return "CustomerForm";
} else {
status.setComplete();
//form success
return "CustomerSuccess";
}
}
//...

Full Example

See a complete

@Controller

example.

package com.mkyong.customer.controller;

import java.sql.Date;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.propertyeditors.CustomDateEditor;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.support.SessionStatus;

import com.mkyong.customer.model.Customer;
import com.mkyong.customer.validator.CustomerValidator;

@Controller
@RequestMapping("/customer.htm")
public class CustomerController{

CustomerValidator customerValidator;

@Autowired
public CustomerController(CustomerValidator customerValidator){
this.customerValidator = customerValidator;
}

@RequestMapping(method = RequestMethod.POST)
public String processSubmit(
@ModelAttribute("customer") Customer customer,
BindingResult result, SessionStatus status) {

customerValidator.validate(customer, result);

if (result.hasErrors()) {
//if validator failed
return "CustomerForm";
} else {
status.setComplete();
//form success
return "CustomerSuccess";
}
}

@RequestMapping(method = RequestMethod.GET)
public String initForm(ModelMap model){

Customer cust = new Customer();
//Make "Spring MVC" as default checked value
cust.setFavFramework(new String []{"Spring MVC"});

//Make "Make" as default radio button selected value
cust.setSex("M");

//make "Hibernate" as the default java skills selection
cust.setJavaSkills("Hibernate");

//initilize a hidden value
cust.setSecretValue("I'm hidden value");

//command object
model.addAttribute("customer", cust);

//return form view
return "CustomerForm";
}

@ModelAttribute("webFrameworkList")
public List<String> populateWebFrameworkList() {

//Data referencing for web framework checkboxes
List<String> webFrameworkList = new ArrayList<String>();
webFrameworkList.add("Spring MVC");
webFrameworkList.add("Struts 1");
webFrameworkList.add("Struts 2");
webFrameworkList.add("JSF");
webFrameworkList.add("Apache Wicket");

return webFrameworkList;
}

@InitBinder
public void initBinder(WebDataBinder binder) {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");

binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));

}

@ModelAttribute("numberList")
public List<String> populateNumberList() {

//Data referencing for number radiobuttons
List<String> numberList = new ArrayList<String>();
numberList.add("Number 1");
numberList.add("Number 2");
numberList.add("Number 3");
numberList.add("Number 4");
numberList.add("Number 5");

return numberList;
}

@ModelAttribute("javaSkillsList")
public Map<String,String> populateJavaSkillList() {

//Data referencing for java skills list box
Map<String,String> javaSkill = new LinkedHashMap<String,String>();
javaSkill.put("Hibernate", "Hibernate");
javaSkill.put("Spring", "Spring");
javaSkill.put("Apache Wicket", "Apache Wicket");
javaSkill.put("Struts", "Struts");

return javaSkill;
}

@ModelAttribute("countryList")
public Map<String,String> populateCountryList() {

//Data referencing for java skills list box
Map<String,String> country = new LinkedHashMap<String,String>();
country.put("US", "United Stated");
country.put("CHINA", "China");
country.put("SG", "Singapore");
country.put("MY", "Malaysia");

return country;
}
}

To make annotation work, you have to enable the component auto scanning feature in Spring.

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"> 
<context:component-scan base-package="com.mkyong.customer.controller" />

<bean class="com.mkyong.customer.validator.CustomerValidator" />

<!-- Register the Customer.properties -->
<bean id="messageSource"
class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basename" value="com/mkyong/customer/properties/Customer" />
</bean>

<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver" >
<property name="prefix">
<value>/WEB-INF/pages/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
</beans>