Spring MVC Form Handling Annotation Example

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.GET

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 webFrameworkList = new ArrayList();
 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

Annotation

@ModelAttribute("webFrameworkList")
public List populateWebFrameworkList() {

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

 return webFrameworkList;
}

Spring’s form

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

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 populateWebFrameworkList() {
 
  //Data referencing for web framework checkboxes
  List webFrameworkList = new ArrayList();
  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 populateNumberList() {
 
  //Data referencing for number radiobuttons
  List numberList = new ArrayList();
  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 populateJavaSkillList() {
 
  //Data referencing for java skills list box
  Map javaSkill = new LinkedHashMap();
  javaSkill.put("Hibernate", "Hibernate");
  javaSkill.put("Spring", "Spring");
  javaSkill.put("Apache Wicket", "Apache Wicket");
  javaSkill.put("Struts", "Struts");
 
  return javaSkill;
 }
 
 @ModelAttribute("countryList")
 public Map populateCountryList() {
 
  //Data referencing for java skills list box
  Map country = new LinkedHashMap();
  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.

 
 
 
 
 
  
 
  
 
 
 
              
                 /WEB-INF/pages/
              
              
                 .jsp