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.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<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>