The 'session' scoped bean lives within a HTTP Session. We already have seen an example of 'session' scoped bean by using JSR 330 Provider approach. In following example, we will create 'session' scoped bean by using class based proxy.
Example
Creating session scoped bean
@Component
@Scope(value = WebApplicationContext.SCOPE_SESSION, proxyMode = ScopedProxyMode.TARGET_CLASS)
public class VisitorInfo implements Serializable {
private String name;
private int visitCounter;
private LocalDateTime firstVisitTime;
//getters/setters
.............
}
Injecting session bean to Controller
@Controller
public class MyController {
@Autowired
private VisitorInfo visitorInfo;
@RequestMapping("/**")
public String appHandler(Model model) {
if (visitorInfo.getName() == null) {
return "main";
}
model.addAttribute("visitor", visitorInfo);
visitorInfo.increaseVisitorCounter();
return "app-page";
}
@PostMapping("/visitor")
public String visitorHandler(String name) {
visitorInfo.setName(name);
visitorInfo.setFirstVisitTime(LocalDateTime.now());
return "redirect:/";
}
}
JSP pages
src/main/webapp/WEB-INF/views/main.jsp<html>
<body>
<h3> Main page <h3>
<p>Enter visitor name</p>
<form action="/visitor" method="post" >
<pre>
Name <input type="text" name="name" />
<input type="submit" value="Submit" />
</pre>
</form>
</body>
</html>
src/main/webapp/WEB-INF/views/app-page.jsp<html>
<body>
<h3>App</h3>
<p>Visitor name: ${visitor.name}</p>
<p>Visit counts: ${visitor.visitCounter}</p>
<p>First Visit at: ${visitor.firstVisitTime}</p>
</body>
</html>
Output
To try examples, run embedded tomcat (configured in pom.xml of example project below):
mvn tomcat7:run-war Accessing http://localhost:8080/
Accessing other URIs:
Visitor name and first access time is remembered through multiple requests and the visit counter increased gradually; that shows that a single VisitorInfo instance is used. A new instance of VisitorInfo will be created at the beginning of new Http Session.
Example ProjectDependencies and Technologies Used: - spring-webmvc 5.0.5.RELEASE: Spring Web MVC.
- javax.servlet-api 3.0.1 Java Servlet API
- JDK 1.8
- Maven 3.3.9
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