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Spring MVC textbox example

2015-09-29 11:36 447 查看

spring的便签带来了什么新功能？

In Spring MVC, you can use

<form:input />

tag to render a HTML textbox field. For example,

<form:input path="userName" />

It will renders following HTML code

<input id="userName" name="userName" type="text" value=""/>

In this tutorial, we show you how to use Spring’s form tag “

input

” to render a HTML textbox to store the “

userName

“. Additionally, add an empty check validator to make sure the textbox value is not empty.

1. Controller

SimpleFormController

to handle the form value, and link the form value to the

Customer

object.

File :

TextBoxController.java

package com.mkyong.customer.controller;

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 TextBoxController extends SimpleFormController{

public TextBoxController(){
setCommandClass(Customer.class);
setCommandName("customerForm");
}

@Override
protected ModelAndView onSubmit(HttpServletRequest request,
HttpServletResponse response, Object command, BindException errors)
throws Exception {

Customer customer = (Customer)command;
return new ModelAndView("CustomerSuccess","customer",customer);

}
}

2. Model

Customer

object to store the text box value.

File :

Customer.java

package com.mkyong.customer.model;

public class Customer{

String userName;
//getter and setter methods
}

3. Form Validator

Create a form validator class and use the

ValidationUtils

class to make sure the “

userName

” is not empty, Otherwise, get the “

required.userName

” message from the corresponds resource bundle (properties file).

File :

CustomerValidator.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 CustomerValidator 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) {

ValidationUtils.rejectIfEmptyOrWhitespace(errors, "userName",
"required.userName", "Field name is required.");

}

}

File :

message.properties

required.userName = username is required!

4. View

A JSP page to use the Spring’s form tag “

input

” to render a HTML textbox, and put some CSS styles to highlight the error message.

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 textbox example</h2>

<form:form method="POST" commandName="customerForm">
<form:errors path="*" cssClass="errorblock" element="div" />
<table>
<tr>
<td>Username :</td>
<td><form:input path="userName" />
</td>
<td><form:errors path="userName" cssClass="error" />
</td>
</tr>
<tr>
<td colspan="3"><input type="submit" />
</td>
</tr>
</table>
</form:form>

</body>
</html>

If the form is submitted, render the successful page and display the submitted textbox value.

File :

CustomerSuccess.jsp

<html>
<body>
<h2>Spring's form textbox example</h2>

userName : ${customer.userName}

</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.TextBoxController">
<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>

<!-- 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/textbox.htm

If the textbox value is empty while submitting the form, display and highlight the error message.

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

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