Java自学笔记之struts访问ServletAPI

1、Action对ServletAPI的访问有两种方式，分别是间接访问和直接访问。
2、使用ServletActionContext访问Servlet API

HttpServletRequest request = ServletActionContext.getRequest();        HttpServletResponse response = ServletActionContext.getResponse();        ServletContext application = ServletActionContext.getServletContext();        PageContext pageContext = ServletActionContext.getPageContext();        Map<String, Object> session = ServletActionContext.getContext().getSession();

3、Action直接访问Servlet API，也就是注入方式
Struts2提供了如下几个接口使Action可以直接访问到Servlet API：
3.1：ServletContextAware：实现该接口的Action可以直接访问Web应用的ServletContext实例
3.2：ServletRequestAware:实现该接口的Action可以直接访问Web应用的ServletRequest实例.
3.3：ServletResponseAware:实现该接口的Action可以直接访问Web应用的ServletRsponse实例.
3.4：SessionAware实现该接口的Action可以直接访问Web应用的Map Session实例.

public class ContextAction02 extends ActionSupport     implements ServletRequestAware, ServletResponseAware, ServletContextAware, SessionAware{    HttpServletRequest request;    HttpServletResponse response;    Map sessionMap;    ServletContext sc;    public String test(){        System.out.println("ContextAction *********** test()");        request.setAttribute("username", "username_request");        sessionMap.put("username", "username_session");        sc.setAttribute("username", "username_application");        return "attr";    }    public void setSession(Map<String, Object> session) {        this.sessionMap = session;    }    public void setServletContext(ServletContext context) {        this.sc = context;    }    public void setServletResponse(HttpServletResponse response) {        this.response = response;    }    public void setServletRequest(HttpServletRequest request) {        this.request = request;    }}

4、通过ActionContext 访问

ActionContext有以下方法，将ServletAPI封装成Map集合了

// 创建一个ActionContextduixangActionContext context=ActionContext.getContext();通过context对象获取Servlet API// ActionContext有以下方法Map<String,Object> getApplication()// 获取applicationMap<String,Object> getParameters() //相当于 request.getParameterMap();Map<String,Object> getSession(); //获取sessionput(String key,Object value); //相当于request.setAttribute();Object get(String key) //相当于request.getAttribute();

public class UserAddAction extends ActionSupport {      private String userName;      private String password;      @Override      public String execte() throws Exception {          ActionContext ac = ActionContext.getContext();          ac.getApplication.put("uname", userName);          ac.getApplication.put("upwd", password);          return SUCCESS;      }  }