<?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"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
"
id="WebApp_ID" version="2.5">
<display-name>Spring MVC Flash attribute example</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>default</servlet-name>
<url-pattern>/index.html</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
</web-app>
然后，spring-servlet 使用 mvc:annotation-driven 来支持 mvc ，并且会扫描项目中的 context:component-scan 标签。
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/context http://www.springframework.org/schema/mvc ">
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property
value="org.springframework.web.servlet.view.JstlView" />
<property value="/WEB-INF/jsp/" />
<property value=".jsp" />
</bean>
<context:component-scan base-package="net.viralpatel.controller" />
<mvc:annotation-driven />
</beans>
Controller 的代码使用 Customer.java 对象作为 bean 来保存客户信息。
Customer.java
package net.viralpatel.spring;
public class Customer {
private String firstname;
private String lastname;
private int age;
private String email;
//getter, setter methods
}
CustomerController 类有3个方法。showForm 方法对应 URL /form ，用来显示 Add New Customer 表单。addCustomer 方法对应 URL /addcustomer ，用来处理 POST 请求。
CustomerController.java
package net.viralpatel.controller;
import net.viralpatel.spring.Customer;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;
@Controller
public class CustomerController {
@RequestMapping(value="showform", method=RequestMethod.GET)
public String showForm(@ModelAttribute("customer") Customer customer) {
return "add_customer";
}
@RequestMapping(value="addcustomer", method=RequestMethod.POST)
public String addCustomer(@ModelAttribute("customer") Customer customer,
final RedirectAttributes redirectAttributes) {
redirectAttributes.addFlashAttribute("customer", customer);
redirectAttributes.addFlashAttribute("message","Added successfully.");
return "redirect:showcustomer.html";
}
@RequestMapping(value="showcustomer", method=RequestMethod.GET)
public String showCustomer(@ModelAttribute("customer") Customer customer) {
System.out.println("cust:" + customer.getFirstname());
return "show_customer";
}
}
注意我们在 addCustomer 方法中是如何使用 redirectAttributes 参数来添加 flash attribute 的。并且，我们是用 addFlashAttribute 方法来设置新的参数为 flash attribute。
第4步: View 层add customer.JSP 文件显示一个 Add New Customer（添加新客户）表单。
add_customer.jsp
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<html>
<body>
<h1>Add New Customer</h1>
<form:form action="addcustomer.html" method="post" commandName="customer">
<table>
<tr>
<td><form:label path="firstname">Firstname</form:label></td>
<td><form:input path="firstname" /> </td>
</tr>
<tr>
<td><form:label path="lastname">Lastname</form:label></td>
<td><form:input path="lastname" /> </td>
</tr>
<tr>
<td><form:label path="age">Age</form:label></td>
<td><form:input path="age" /> </td>
</tr>
<tr>
<td><form:label path="email">Email</form:label>
<td><form:input path="email" /> </td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="Add Customer" />
</td>
</tr>
</table>
</form:form>
</body>
</html>
show_customer.jsp 简单地显示客户的名和姓，以及用 flash attributes 设置的成功信息。
show_customer.jsp