Action 訪問 Servlet API 的方式

這里只針對 Servlet 中常用的，如 HttpServletRequest、HttpServletResponse 和 HttpSession 來展開。
一般來說，在 Struts2 中訪問 Servlet API 的方式有2種：
(1) 直接訪問 Servlet API。這將會使得你的 Action 類與 Servlet API 耦合在一起。
(2) 通過 Struts2 API 來訪問 Servlet API，這樣 Action 類就不會再跟 Servlet API 耦合。

通過 ServletActionContext 來訪問 Servlet API ( 耦合 )

package fan.tutorial.action;

import com.opensymphony.xwork2.Action;

import javax.servlet.http.HttpSession;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;

public class ServletApiAction implements Action {

    private HttpSession session;

    private HttpServletRequest request;

    private HttpServletResponse response;

    public String execute() throws Exception {

        request = ServletActionContext.getRequest();

        session = request.getSession();

        response = ServletActionContext.getResponse();

        request.setAttribute("requestScopeParam", "fan");

        session.setAttribute("sessionScopeParam", "tutorial");

        response.setHeader("expires", "-1");

        response.setHeader("Pragma", "no-cache");

        response.setHeader("Cache-Control", "no-cache");

        return SUCCESS;

    }

}

通過 ServletRequestAware、ServletResponseAware 接口來訪問 Servlet API ( 耦合 )

package fan.tutorial.action;

import javax.servlet.http.HttpSession;

import com.opensymphony.xwork2.Action;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.interceptor.ServletRequestAware;

import org.apache.struts2.interceptor.ServletResponseAware;

public class IServletApiAction implements Action, ServletRequestAware, ServletResponseAware {

    private HttpSession session;

    private HttpServletRequest request;

    private HttpServletResponse response;

    public String execute() throws Exception {

        request.setAttribute("requestScopeParam", "fan");

        session.setAttribute("sessionScopeParam", "tutorial");

        response.setHeader("expires", "-1");

        response.setHeader("Pragma", "no-cache");

        response.setHeader("Cache-Control", "no-cache");

        return SUCCESS;

    }

    public void setServletRequest(HttpServletRequest request) {

        this.request = request;

        this.session = request.getSession();

    }

    public void setServletResponse(HttpServletResponse response) {

        this.response = response;

    }

}

通過 ActionContext 來訪問 Servlet API ( 解耦 )

package fan.tutorial.action;

import java.util.Map;

import com.opensymphony.xwork2.Action;

import com.opensymphony.xwork2.ActionContext;

public class StrutsServletApiAction implements Action {

    private Map<String, Object> session;

    private Map<String, Object> request;

    private ActionContext context = ActionContext.getContext();

    public String execute() throws Exception {

        session = context.getSession();

        request = (Map<String, Object>)context.get("request");

        request.put("requestScopeParam", "fan");

        session.put("sessionScopeParam", "tutorial");

        return SUCCESS;

    }

}

通過 RequestAware、SessionAware 接口來訪問 Servlet API ( 解耦 )

package fan.tutorial.action;

import java.util.Map;

import com.opensymphony.xwork2.Action;

import org.apache.struts2.interceptor.RequestAware;

import org.apache.struts2.interceptor.SessionAware;

public class IStrutsServletApiAction implements Action, RequestAware, SessionAware {

    private Map<String, Object> session;

    private Map<String, Object> request;

    public String execute() throws Exception {

        request.put("requestScopeParam", "fan");

        session.put("sessionScopeParam", "tutorial");

        return SUCCESS;

    }

    public void setRequest(Map<String, Object> request) {

        this.request = request;

    }

    public void setSession(Map<String, Object> session) {

        this.session = session;

    }

}