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SessionAware Interface Example

The SessionAware interface must be implemented by the Action class to store the information in the session scope.

Method of SessionAware interface

It contains only one method setSession.

Public and abstract MethodDescription
void setSession(Map<String,Object> map) struts framework calls this method by passing the instance of SessionMap class.

SessionMap class

The struts 2 framework passes the instance of org.apache.struts2.dispatcher.SessionMap. It extends the java.util.AbstractMap class which implements the java.util.Map.SessionMap. There are many useful methods of SessionMap class.

Methods of SessionMap class

The commonly used methods of SessionMap class are as follows:

MethodsDescription
public Object put(Object key, Object value) stores an attribute in the HttpSession object.
public Object remove(Object key) removes the attribute for the specified key and returns the attribute value.
public Object get(Object key) return a value for the corresponding key from the HttpSession object.
public Set entrySet() returns a set object containing all the key and value objects set in the HttpSession object.
public void invalidate() invalidates the current HttpSession object.
public void clear() removes all the attributes set in the HttpSession object.

Example of SessionAware interface

This example contains three links login, logout and profile. You cannot click on the profile page untill you are logged in. After getting logged in, you may go to the profile page. If the end user clicks on the logout link, he will not be able to access the profile page.

Steps are as follows:

  1. add struts and servlet library
  2. index.jsp for providing links to the login, logout and profile.
  3. struts.xml for defining the result and action.
  4. Login.java for defining login and logout logic.
  5. Profile.java for checking if the user is logged in or not.
  6. View components for the displaying results.

1) Add struts and servlet library

You need to add struts 2 and servlet library.


2) Create index.jsp for input

This jsp page creates three links for login, logout and profile.

index.jsp

3) Define action and result in struts.xml

This xml file defines one package and 4 actions. Each action defines at least one result page.

For the loginprocess and logout actions, we are using the same action class but there invocation methods are different.

struts.xml

4) Create the action class for login and logout

This action class implements the SessionAware interface and overrides the setSession method to store the information in the session scope.

For logout, we are simply calling the invalidate() method of SessionMap.

Login.java

5) Create the Profile class

This class gets the information from the session scope, if any information is found in the session scope with login name, it returns success otherwise false.

Profile.java

6) Create view components

There are many view components:

  • login.jsp
  • login-success.jsp
  • login-error.jsp
  • logout-success.jsp
  • profile-success.jsp
  • profile-error.jsp

view components for login

login.jsp

This page creates the login form.

login-success.jsp

This page prints the welcome message with the username.

login-error.jsp

This page displays the error message.


view components for logout

logout-success.jsp

This page simply displays the successfully logged out message.


view components for profile

profile-success.jsp

This page prints the welcome to profile message.

profile-error.jsp

This page prints the message to login first and includes the login.jsp page.



Output

struts 2 sessionaware example output 1

If you click on the profile link, you will be forwarded to profile-error.jsp

struts 2 sessionaware example output 2

Now write your name for name and admin for the password.

struts 2 sessionaware example output 3

Now, you are successfully logged in

struts 2 sessionaware example output 4

Now, click on the profile.

struts 2 sessionaware example output 5

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