Struts2 Study Notes (5) -- Action access Servlet API, struts2servlet

Struts2 Study Notes (5) -- Action access Servlet API, struts2servlet

There are three methods to access Servlet APIs in Strut2:

1. Using ActionContext to access the Servlet API is recommended. However, this solution does not obtain the actual Servlet API.

Steps:
1) Create an ActionContext

• ActionContext context = ActionContext. getContext ();

2). Get the Servlet API through the context object

• Map <String, Object> getApplication () obtains all information stored in the application.
• Map <String, Object> getParameters () is equivalent to request. getParameterMap ();
• Map <String, Object> getSession (); obtains all the information stored in the session.
• Put (String key, Object value); is equivalent to request. setAttribute ();
• Object get (String key) is equivalent to request. getAttribute ();

2. Inject (real Servlet API)

Use the * Aware interface to obtain the Servlet API, for example:

• ServletContextAware: injects the ServletContext object
• ServletRequestAware: injects the request object
• ServletResponseAware: injects a response object.

For example, to obtain the HttpServletRequest object:

 1 public class TestAction extends ActionSupport implements ServletRequestAware { 2     HttpServletRequest request; 3     @Override 4     public String execute() { 5         request.setAttribute("name", "requestTest"); 6         return "success"; 7     } 8      9     @Override10     public void setServletRequest(HttpServletRequest request) {11         this.request = request;12     }13 14 }

3. Use ServletActionContext (real Servlet API)

Through the static method provided in the ServletActionContext class, you can directly obtain the Servlet API:

1 // obtain request2 HttpServletRequest request = ServletActionContext. getRequest (); 3 // get session4 HttpSession session = request. getSession (); 5 // get context6 ServletContext context = ServletActionContext. getServletContext ();