In Spring MVC, <form:radiobutton /> is used to render a HTML radio button, and the radio button values are hard coded inside the JSP page; While the <form:radiobuttons /> is used to render multiple radio buttons, and the radio button values are generated at runtime.

In this tutorial, we show you how to use <form:radiobutton /> and <form:radiobuttons />.

1. <form:radiobutton />

Generate a radio button, and hard-coded the value.

public class Customer{
	String sex;
	//...
}
<form:radiobutton path="sex" value="M"/>Male 
<form:radiobutton path="sex" value="F"/>Female
Default value…
To make the “Male” as the default selected value in above radio buttons, just set the “sex” property to “M“, for example :

public class Customer{
	String sex = "M";
	//...
}

or

//SimpleFormController...
@Override
protected Object formBackingObject(HttpServletRequest request)
	throws Exception {
 
	Customer cust = new Customer();
	//Make "Male" as the default radio button selected value
	cust.setSex("M");
 
	return cust;
 
}

2. <form:radiobuttons />

Generate multiple radio buttons, and the values are generated at runtime.

//SimpleFormController...
protected Map referenceData(HttpServletRequest request) throws Exception {
 
	Map referenceData = new HashMap();
 
	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");
	referenceData.put("numberList", numberList);
 
	return referenceData;		
}
<form:radiobuttons path="favNumber" items="${numberList}"  />
Default value…
To make the “Number 1” as the default selected value in above radio buttons, just set the “favNumber” property to “Number 1“, for example :

public class Customer{
	String favNumber = "Number 1";
	//...
}

or

//SimpleFormController...
@Override
protected Object formBackingObject(HttpServletRequest request)
	throws Exception {
 
	Customer cust = new Customer();
	//Make "Number 1" as the default radio button selected value
	cust.setFavNumber("Number 1")
 
	return cust;	
}
Note
For radio button selection, as long as the “path” or “property” is equal to the “radio button value“, the radio button will be selected automatically.

Full radio button example

Let’s go thought a complete Spring MVC radio button example :

1. Model

A customer model class to store the radio button value.

File : Customer.java

package com.mkyong.customer.model;
 
public class Customer{
 
	String favNumber;
	String sex;
 
	public String getFavNumber() {
		return favNumber;
	}
	public void setFavNumber(String favNumber) {
		this.favNumber = favNumber;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
 
}

2. Controller

A SimpleFormController to handle the form radio button value. Make the radio button “M” as the default selected value.

File : RadioButtonController.java

package com.mkyong.customer.controller;
 
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.validation.BindException;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.SimpleFormController;
import com.mkyong.customer.model.Customer;
 
public class RadioButtonController extends SimpleFormController{
 
	public RadioButtonController(){
		setCommandClass(Customer.class);
		setCommandName("customerForm");
	}
 
	@Override
	protected Object formBackingObject(HttpServletRequest request)
		throws Exception {
 
		Customer cust = new Customer();
		//Make "Make" as default radio button checked value
		cust.setSex("M");
 
		return cust;
	}
 
	@Override
	protected ModelAndView onSubmit(HttpServletRequest request,
		HttpServletResponse response, Object command, BindException errors)
		throws Exception {
 
		Customer customer = (Customer)command;
		return new ModelAndView("CustomerSuccess","customer",customer);
	}
 
	protected Map referenceData(HttpServletRequest request) throws Exception {
 
		Map referenceData = new HashMap();
 
		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");
		referenceData.put("numberList", numberList);
 
		return referenceData;
	}
}

3. Validator

A simple form validator to make sure the “sex” and “number” radio button is selected.

File : RadioButtonValidator.java

package com.mkyong.customer.validator;
 
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
 
import com.mkyong.customer.model.Customer;
 
public class RadioButtonValidator implements Validator{
 
	@Override
	public boolean supports(Class clazz) {
		//just validate the Customer instances
		return Customer.class.isAssignableFrom(clazz);
	}
 
	@Override
	public void validate(Object target, Errors errors) {
 
		Customer cust = (Customer)target;
 
		ValidationUtils.rejectIfEmptyOrWhitespace(errors, "sex", "required.sex");
		ValidationUtils.rejectIfEmptyOrWhitespace(errors, "favNumber", "required.favNumber");
 
	}
}

File : message.properties

required.sex = Please select a sex!
required.favNumber = Please select a number!

4. View

A JSP page to show the use of Spring’s form tag <form:radiobutton /> and <form:radiobuttons />.

File : CustomerForm.jsp

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<html>
<head>
<style>
.error {
	color: #ff0000;
}
 
.errorblock {
	color: #000;
	background-color: #ffEEEE;
	border: 3px solid #ff0000;
	padding: 8px;
	margin: 16px;
}
</style>
</head>
 
<body>
	<h2>Spring's form radio button example</h2>
 
	<form:form method="POST" commandName="customerForm">
		<form:errors path="*" cssClass="errorblock" element="div" />
		<table>
			<tr>
				<td>Sex :</td>
				<td><form:radiobutton path="sex" value="M" />Male <form:radiobutton
					path="sex" value="F" />Female</td>
				<td><form:errors path="sex" cssClass="error" /></td>
			</tr>
			<tr>
				<td>Choose a number :</td>
				<td><form:radiobuttons path="favNumber" items="${numberList}" />
                                </td>
				<td><form:errors path="favNumber" cssClass="error" /></td>
			</tr>
			<tr>
				<td colspan="3"><input type="submit" /></td>
			</tr>
		</table>
	</form:form>
 
</body>
</html>

Use JSTL to loop over the submitted radio button values, and display it.

File : CustomerSuccess.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
 
<html>
<body>
	<h2>Spring's form radio button example</h2>
	Sex : ${customer.sex}
	<br /> Favourite Number : ${customer.favNumber}
	<br />
</body>
</html>

5. Spring Bean Configuration

Link it all ~

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
	http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
 
  <bean
  class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping" />
 
	<bean class="com.mkyong.customer.controller.RadioButtonController">
		<property name="formView" value="CustomerForm" />
		<property name="successView" value="CustomerSuccess" />
 
		<!-- Map a validator -->
		<property name="validator">
			<bean class="com.mkyong.customer.validator.RadioButtonValidator" />
		</property>
	</bean>
 
	<!-- Register the Customer.properties -->
	<bean id="messageSource"
		class="org.springframework.context.support.ResourceBundleMessageSource">
		<property name="basename" value="message" />
	</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>

6. Demo

Access the page – http://localhost:8080/SpringMVCForm/radiobutton.htm

SpringMVC-RadioButton-Example-1

If the user did not select any radio button value while submitting the form, display and highlight the error message.

SpringMVC-RadioButton-Example-2

If the form is submitted successfully, just display the submitted radio button values.

SpringMVC-RadioButton-Example-3

Download Source Code

Download it – SpringMVCForm-RadioButton-Example.zip (9KB)
Any Java questions or problems? please post at this JavaNullPointer.com forum, see you there ~
[ Read More ] You can find more similar articles at Spring MVC Tutorials