Struts2-学习笔记系列(4)-访问servlet api

5.1通过actioncontext：

 public String execute() throws Exception {

     ActionContext ctx = ActionContext.getContext();

     // 通过ActionContext访问application范围的属性值

     Integer counter = (Integer) ctx.getApplication().get("counter");

     if (counter == null) {

         counter = 1;

     } else {

         counter = counter + 1;

     }

     // 通过ActionContext设置application范围的属性

     ctx.getApplication().put("counter", counter);

     // 通过ActionContext设置session范围的属性

     ctx.getSession().put("user", getUser());

     if (getUser().equals("zcx")) {

         // 通过ActionContext设置request范围的属性

         ctx.put("tip", "欢迎登录");

         return SUCCESS;

     }

     // 通过ActionContext设置request范围的属性

     ctx.put("tip", "登录失败");

     return ERROR;

 }

取数据：注意写在HTML页面的OGNL表达式语法

${applicationScope.counter}
${sessionScope.user}
${requestScope.tip}

5.2实现servletcontextaware、servletrequestaware、servletresponseaware

实现ServletResponseAware 设置cookie

 public class LoginAction implements Action, ServletResponseAware {

     private String user;

     private String pwd;

     private String tip;

     private HttpServletResponse response;

     public String getPwd() {

         return pwd;

     }

     public void setPwd(String pwd) {

         this.pwd = pwd;

     }

     public String getUser() {

         return user;

     }

     public void setUser(String user) {

         this.user = user;

     }

     public String execute() throws Exception {

         ActionContext ctx = ActionContext.getContext();

         // 通过ActionContext访问application范围的属性值

         Integer counter = (Integer) ctx.getApplication().get("counter");

         if (counter == null) {

             counter = 1;

         } else {

             counter = counter + 1;

         }

         // 通过ActionContext设置application范围的属性

         ctx.getApplication().put("counter", counter);

         // 通过ActionContext设置session范围的属性

         ctx.getSession().put("user", getUser());

         if (getUser().equals("zcx")) {

             // 通过response添加Cookie

             Cookie c = new Cookie("user", getUser());

             c.setMaxAge(60 * 60);

             response.addCookie(c);

             // 通过ActionContext设置request范围的属性

             ctx.put("tip", "服务器提示：您已经成功的登录");

             return SUCCESS;

         }

         // 通过ActionContext设置request范围的属性

         ctx.put("tip", "登录失败");

         return ERROR;

     }

     public String getTip() {

         return tip;

     }

     public void setTip(String tip) {

         this.tip = tip;

     }

     @Override

     public void setServletResponse(HttpServletResponse httpServletResponse) {

         this.response = response;

     }

 }

5.3使用servletactioncontext

 public class LoginAction implements Action {

     private String user;

     private String pwd;

     private String tip;

     private HttpServletResponse response;

     public String getPwd() {

         return pwd;

     }

     public void setPwd(String pwd) {

         this.pwd = pwd;

     }

     public String getUser() {

         return user;

     }

     public void setUser(String user) {

         this.user = user;

     }

     public String execute() throws Exception {

         ActionContext ctx = ActionContext.getContext();

         // 通过ActionContext访问application范围的属性值

         Integer counter = (Integer) ctx.getApplication().get("counter");

         if (counter == null) {

             counter = 1;

         } else {

             counter = counter + 1;

         }

         // 通过ActionContext设置application范围的属性

         ctx.getApplication().put("counter", counter);

         // 通过ActionContext设置session范围的属性

         ctx.getSession().put("user", getUser());

         if (getUser().equals("zcx")) {

             // 通过response添加Cookie

             Cookie c = new Cookie("user", getUser());

             c.setMaxAge(60 * 60);

             ServletActionContext.getResponse().addCookie(c);

             // 通过ActionContext设置request范围的属性

             ctx.put("tip", "服务器提示：您已经成功的登录");

             return SUCCESS;

         }

         // 通过ActionContext设置request范围的属性

         ctx.put("tip", "登录失败");

         return ERROR;

     }

     public String getTip() {

         return tip;

     }

     public void setTip(String tip) {

         this.tip = tip;

     }

 }