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Il tag del campo di testo del modulo Spring MVC utilizza il valore di binding per generare etichette di input HTML. Per impostazione predefinita, il tipo di etichetta di input è testo.
<form:input path="name" />
Ecco qui: path L'attributo lega il campo del modulo al attributo del bean.
La libreria di etichette dei moduli Spring MVC offre anche altri tipi di input, come email, data, telefono, ecc.
<form:input type="email" path="email" />
<form:input type="date" path="date" />
Ecco un esempio di creazione di un modulo di prenotazione ferroviaria utilizzando la libreria di etichette dei moduli.
<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>5.1.1.RELEASE</version> </dependency> <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api --> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>3.0-alpha-1</version> </dependency> <!-- https://mvnrepository.com/artifact/javax.servlet/jstl --> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-jasper --> <dependency> <groupId>org.apache.tomcat</groupId> <artifactId>tomcat-jasper</artifactId> <version>9.0.12</version> </dependency>
In questo contesto, la classe bean contiene variabili corrispondenti ai campi di input presenti nel modulo (nonché ai metodi setter e getter).
Reservation.java
package com.w3codebox;
public class Reservation {
private String firstName;
private String lastName;
public Reservation() {
{
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}
ReservationController.java
package com.w3codebox;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
@RequestMapping("/reservation")
@Controller
public class ReservationController {
@RequestMapping("/bookingForm")
public String bookingForm(Model model)
{
// create a reservation object
Reservation res = new Reservation();
// provide reservation object to the model
model.addAttribute("reservation", res);
return "reservation-page";
}
@RequestMapping("/submitForm")
// @ModelAttribute binds form data to the object
public String submitForm(@ModelAttribute("reservation") Reservation res)
{
return "confirmation-form";
}
}
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>SpringMVC</display-name> <servlet> <servlet-name>spring</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>spring</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
spring-servlet.xml
<?xml version="1.0" encoding="UTF-8"?> <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" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!-- Fornire supporto per la scansione dei componenti --> <context:component-scan base-package="com.w3codebox" /> <!-- Fornire supporto per la conversione, formattazione e convalida --> <mvc:annotation-driven/> <!-- Definire il risolutore di vista Spring MVC --> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/"></property> <property name="suffix" value=".jsp"></property> </bean> </beans>
index.jsp
<!DOCTYPE html> <html> <head> <title>Modulo di registrazione ferroviaria</title> </head> <body> <a href="reservation/bookingForm">Clicca qui per la prenotazione.</a> </body> </html>
reservation-page.jsp
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %> <!DOCTYPE html> <html> <head> <title>Modulo di prenotazione</title> </head> <h3>Modulo di prenotazione ferroviaria</h3> <body> <form:form action="submitForm" modelAttribute="reservation"> Nome: <form:input path="firstName" /> <br><br> Cognome: <form:input path="lastName" /> <br><br> <input type="submit" value="Invia" /> </form:form> </body> </html>
confirmation-page.jsp
<!DOCTYPE html>
<html>
<body>
<p>La tua prenotazione è stata confermata con successo. Per favore, rivedi i dettagli.</p>
Nome: ${reservation.firstName} <br>
Cognome: ${reservation.lastName}
</body>
</html>
Output: