Spring MVC checkbox and checkboxes example

In Spring MVC, <form:checkbox /> is used to render a HTML checkbox field, the checkbox values are hard-coded inside the JSP page; While the <form:checkboxes /> is used to render multiple checkboxes, the checkbox values are generated at runtime.

In this tutorial, we show you 3 different ways of render HTML checkbox fields:

1. <form:checkbox /> – Single Checkbox

Generate a classic single checkbox, with a boolean value.

public class Customer{    boolean receiveNewsletter;    //...}

<form:checkbox path="receiveNewsletter" />

Checked by default…
If you set the “receiveNewsletter” boolean value to true, this checkbox will be checked. For example :
“`
public class Customer{
boolean receiveNewsletter = true;
//…
}

##2. `<form:checkbox />` – Multiple CheckboxesGenerate multiple checkboxes and hard-coded the value.

public class Customer{
String [] favLanguages;
//…
}

```<form:checkbox path="favLanguages" value="Java"/>Java <form:checkbox path="favLanguages" value="C++"/>C++ <form:checkbox path="favLanguages" value=".Net"/>.Net

Checked by default…
If you want to make the checkbox with value “Java” is checked by default, you can initialize the “favLanguages” property with value “Java”. For example :

        //SimpleFormController...        @Override    protected Object formBackingObject(HttpServletRequest request)        throws Exception {        Customer cust = new Customer();        cust.setFavLanguages(new String []{"Java"});        return cust;    }

3. <form:checkboxes /> – Multiple Checkboxes

Generate a runtime list for the checkboxes value, and link it to Spring’s form tag <form:checkboxes>.

        //SimpleFormController...    protected Map referenceData(HttpServletRequest request) throws Exception {        Map referenceData = new HashMap();        List<String> webFrameworkList = new ArrayList<String>();        webFrameworkList.add("Spring MVC");        webFrameworkList.add("Struts 1");        webFrameworkList.add("Struts 2");        webFrameworkList.add("Apache Wicket");        referenceData.put("webFrameworkList", webFrameworkList);        return referenceData;    }

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

Checked by default…
If you want to make 2 checkboxes with value “Spring MVC” and “Struts 2″ are checked by default, you can initialize the “favFramework” property with value “Spring MVC” and “Struts 2″. Fro example :

         //SimpleFormController...        @Override    protected Object formBackingObject(HttpServletRequest request)        throws Exception {        Customer cust = new Customer();        cust.setFavFramework(new String []{"Spring MVC","Struts 2"});        return cust;    }

Note
<form:checkboxes items="${dynamic-list}" path="property-to-store" />
For multiple checkboxes, as long as the “path” or “property” value is equal to any of the “checkbox values – ${dynamic-list}“, the matched checkbox will be checked automatically.

Full checkbox example

Let’s go thought a complete Spring MVC checkbox example :

1. Model

A customer model class to store the checkbox value.

File : Customer.java

package com.mkyong.customer.model;public class Customer{    //checkbox    boolean receiveNewsletter = true; //checked it    String [] favLanguages;    String [] favFramework;    public String[] getFavFramework() {        return favFramework;    }    public void setFavFramework(String[] favFramework) {        this.favFramework = favFramework;    }    public boolean isReceiveNewsletter() {        return receiveNewsletter;    }    public void setReceiveNewsletter(boolean receiveNewsletter) {        this.receiveNewsletter = receiveNewsletter;    }    public String[] getFavLanguages() {        return favLanguages;    }    public void setFavLanguages(String[] favLanguages) {        this.favLanguages = favLanguages;    }}

2. Controller

A SimpleFormController to handle the form checkbox value.

File : CheckBoxController.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 CheckBoxController extends SimpleFormController{    public CheckBoxController(){        setCommandClass(Customer.class);        setCommandName("customerForm");    }    @Override    protected Object formBackingObject(HttpServletRequest request)        throws Exception {        Customer cust = new Customer();        //Make "Spring MVC" and "Struts 2" as default checked value        cust.setFavFramework(new String []{"Spring MVC","Struts 2"});        //Make "Java" as default checked value        cust.setFavLanguages(new String []{"Java"});        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);    }    //Generate the data for web framework multiple checkboxes    protected Map referenceData(HttpServletRequest request) throws Exception {        Map referenceData = new HashMap();        List<String> webFrameworkList = new ArrayList<String>();        webFrameworkList.add("Spring MVC");        webFrameworkList.add("Struts 1");        webFrameworkList.add("Struts 2");        webFrameworkList.add("Apache Wicket");        referenceData.put("webFrameworkList", webFrameworkList);        return referenceData;    }}

3. Validator

A simple form validator make sure the “favLanguages” property is not empty.

File : CheckBoxValidator.java

package com.mkyong.customer.validator;import org.springframework.validation.Errors;import org.springframework.validation.Validator;import com.mkyong.customer.model.Customer;public class CheckBoxValidator 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;        if(cust.getFavLanguages().length==0){            errors.rejectValue("favLanguages", "required.favLanguages");        }    }}

File : message.properties

required.favLanguages = Please select at least a favorite programming language!

4. View

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

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 checkbox example</h2>    <form:form method="POST" commandName="customerForm">        <form:errors path="*" cssClass="errorblock" element="div" />        <table>            <tr>                <td>Subscribe to newsletter? :</td>                <td><form:checkbox path="receiveNewsletter" /></td>                <td><form:errors path="receiveNewsletter" cssClass="error" /></td>            </tr>            <tr>                <td>Favourite Languages :</td>                <td>                                       <form:checkbox path="favLanguages" value="Java" />Java                                        <form:checkbox path="favLanguages" value="C++" />C++                                        <form:checkbox path="favLanguages" value=".Net" />.Net                                </td>                <td><form:errors path="favLanguages" cssClass="error" />                </td>            </tr>            <tr>                <td>Favourite Web Frameworks :</td>                <td><form:checkboxes items="${webFrameworkList}"                        path="favFramework" /></td>                <td><form:errors path="favFramework" 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 checkboxes value, and display it.

File : CustomerSuccess.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><html><body>    <h2>Spring's form checkbox example</h2>    Receive Newsletter : ${customer.receiveNewsletter}    <br />         Favourite Languages :    <c:forEach items="${customer.favLanguages}" var="current">        [<c:out value="${current}" />]    </c:forEach>    <br />         Favourite Web Frameworks :    <c:forEach items="${customer.favFramework}" var="current">        [<c:out value="${current}" />]    </c:forEach>    <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.CheckBoxController">        <property name="formView" value="CustomerForm" />        <property name="successView" value="CustomerSuccess" />        <!-- Map a validator -->        <property name="validator">            <bean class="com.mkyong.customer.validator.CheckBoxValidator" />        </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/checkbox.htm

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

If the form is submitted successfully, just display the submitted checkboxes value.