Spring MVC Checkbox And Checkboxes Example-白红宇

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;	//...}

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 Checkboxes

Generate multiple checkboxes and hard-coded the value.

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


       Java 
       C++ 
       .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
       
         webFrameworkList = new ArrayList
        
         ();		webFrameworkList.add("Spring MVC");		webFrameworkList.add("Struts 1");		webFrameworkList.add("Struts 2");		webFrameworkList.add("Apache Wicket");		referenceData.put("webFrameworkList", webFrameworkList); 		return referenceData;	}

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

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
       
         webFrameworkList = new ArrayList
        
         ();		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"%> 	Spring's form checkbox example
 	
       		
        		
        
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			          				           Favourite Languages : 				                                                  
            Java                                        
            C++                                        
            .Net                                				           
            				 			          
			          				           Favourite Web Frameworks :

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"%> 	Spring's form checkbox example
 	Receive Newsletter : ${customer.receiveNewsletter}	
          Favourite Languages :	
       
        		[
        ]	
       	
          Favourite Web Frameworks :	
       
        		[
        ]

5. Spring Bean Configuration

Link it all ~


       
           
         	
        		
         		
          		
         		
         			
          		
         	
         	
        	
        		
         	
         	
        		
         			
          
           /WEB-INF/pages/
          		
         		
         			
          
           .jsp

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.

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