这篇文章将为大家详细讲解有关Spring中的 @SessionAttributes注解怎么理解，文章内容质量较高，因此小编分享给大家做个参考，希望大家阅读完这篇文章后对相关知识有一定的了解。
@ModelAttribute注解作用在方法上或者方法的参数上，表示将被注解的方法的返回值或者是被注解的参数作为Model的属性加入到Model中，然后Spring框架自会将这个Model传递给ViewResolver。Model的生命周期只有一个http请求的处理过程，请求处理完后，Model就销毁了。
如果想让参数在多个请求间共享，那么可以用到要说到的@SessionAttribute注解
SessionAttribute只能作用在类上
下面是一个简单的用户登录，@SessionAttributes用来将model属性存在session中
@SessionAttributes("user")public class LoginController { @ModelAttribute("user") public User setUpUserForm() { eturn new User();}}上面的代码表示，加上@ModelAttribute 和 @SessionAttributes 注解的作用，user属性将会被存储在session中
@SessionAttribute 提取session中的属性值
@GetMapping("/info")public String userInfo(@SessionAttribute("user") User user) {//...//...return "user";}项目结构
jar 依赖pom.xml
ndency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>4.3.10.RELEASE</version> </dependency> <!-- JSTL Dependency --> <dependency> <groupId>javax.servlet.jsp.jstl</groupId> <artifactId>javax.servlet.jsp.jstl-api</artifactId> <version>1.2.1</version> </dependency> <dependency> <groupId>taglibs</groupId> <artifactId>standard</artifactId> <version>1.1.2</version> </dependency> <!-- Servlet Dependency --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> <scope>provided</scope> </dependency> <!-- JSP Dependency --> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>javax.servlet.jsp-api</artifactId> <version>2.3.1</version> <scope>provided</scope> </dependency></dependencies>Model类 User.java
package com.boraji.tutorial.spring.model;public class User { private String email; private String password; private String fname; private String mname; private String lname; private int age; // Getter and Setter methods }LoginController.java
package com.boraji.tutorial.spring.controller;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.ModelAttribute;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.SessionAttributes;import com.boraji.tutorial.spring.model.User;@Controller@SessionAttributes("user")public class LoginController { @ModelAttribute("user") public User setUpUserForm() { return new User(); } @GetMapping("/") public String index() { return "index"; } @PostMapping("/dologin") public String doLogin(@ModelAttribute("user") User user, Model model) { // Implement your business logic if (user.getEmail().equals("sunil@example.com") && user.getPassword().equals("abc@123")) { // Set user dummy data user.setFname("Sunil"); user.setMname("Singh"); user.setLname("Bora"); user.setAge(28); } else { model.addAttribute("message", "Login failed. Try again."); return "index"; } return "success"; }}接下来创建另一个Controller，UserController，通过@SessionAttribute从session中取得use的属性
package com.boraji.tutorial.spring.controller;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.SessionAttribute;import com.boraji.tutorial.spring.model.User;@Controller@RequestMapping("/user")public class UserController { @GetMapping("/info") public String userInfo(@SessionAttribute("user") User user) { System.out.println("Email: " + user.getEmail()); System.out.println("First Name: " + user.getFname()); return "user"; }}JSP页面
在src\main\webapp下创建新目录\WEB-INF\views
然后在该目录下创建index.jsp, success.jsp 和 user.jsp
index.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%><%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%><!DOCTYPE html><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>BORAJI.COM</title></head><body> <h2>User Login</h2> <form:form action="dologin" method="post" modelAttribute="user"> <table> <tr> <td>Email</td> <td><form:input path="email" /></td> </tr> <tr> <td>Password</td> <td><form:password path="password" /></td> </tr> <tr> <td><button type="submit">Login</button></td> </tr> </table> </form:form> <span style="color: red;">${message}</span></body></html>success.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%><!DOCTYPE html><html><head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>BORAJI.COM</title> </head> <body> <h2>Login Success Page</h2> <p>You are logged in with email ${user.email}.</p> <!-- Click here to view the session attributes --> <a href="/user/info">View profile</a></body></html>user.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%><!DOCTYPE html><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>BORAJI.COM</title></head><body> <h2>User profile Page</h2> <table> <tr> <td>First Name</td> <td>${user.fname}</td> </tr> <tr> <td>Middle Name</td> <td>${user.mname}</td> </tr> <tr> <td>Last Name</td> <td>${user.lname}</td> </tr> <tr> <td>Age</td> <td>${user.age}</td> </tr> </table></body></html>Spring配置
在根目录下创建WebConfig.java
package com.boraji.tutorial.spring.config;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.ComponentScan;import org.springframework.context.annotation.Configuration;import org.springframework.web.servlet.config.annotation.EnableWebMvc;import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;import org.springframework.web.servlet.view.InternalResourceViewResolver;import org.springframework.web.servlet.view.JstlView;@Configuration@EnableWebMvc@ComponentScan(basePackages = { "com.boraji.tutorial.spring.controller" })public class WebConfig extends WebMvcConfigurerAdapter { @Bean public InternalResourceViewResolver resolver() { InternalResourceViewResolver resolver = new InternalResourceViewResolver(); resolver.setViewClass(JstlView.class); resolver.setPrefix("/WEB-INF/views/"); resolver.setSuffix(".jsp"); return resolver; }}Servlet容器初始化
MyWebAppInitializer.java
package com.boraji.tutorial.spring.config;import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;public class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer { @Override protected Class<?>[] getRootConfigClasses() { return new Class[] {}; } @Override protected Class<?>[] getServletConfigClasses() { return new Class[] { WebConfig.class }; } @Override protected String[] getServletMappings() { return new String[] { "/" }; }}Build + Deploy + Run application
通过下面maven命令，编译、打包、部署、运行程序
mvn clean install (This command triggers war packaging)
mvn tomcat7:run (This command run embedded tomcat and deploy war file automatically)
访问http://localhost:8080/
输入用户名和密码登录成功后，你将看到以下页面
点击页面上的“View profi”查看session中的属性
删除session
@RequestMapping("/endsession")public String nextHandlingMethod2(SessionStatus status){ status.setComplete(); return "lastpage";}关于Spring中的 @SessionAttributes注解怎么理解就分享到这里了，希望以上内容可以对大家有一定的帮助，可以学到更多知识。如果觉得文章不错，可以把它分享出去让更多的人看到。
