Struts2得到Servlet對象的幾種方式

第一種：ActionContext（首選）

public String execute() {
		if ("ping".equals(username)) {
			/*
			 * ActionContext能夠得到Servlet對象 可是沒法得到response響應對象得到
			 * 得到的request、session、Application 都是Map類型
			 */

			ActionContext.getContext().put("用戶名", username);
			ActionContext.getContext().getSession();
			ActionContext.getContext().getApplication();
			Map request=(Map)ActionContext.getContext().get(StrutsStatics.HTTP_REQUEST);
		} else {
			ActionContext.getContext().put("info", "信息");
		}
		return SUCCESS;
	}

第二種: 實現ServletRequestAware，
ServletResponseAware，ServletSessionAware接口（第三選擇 不推薦）

public class LoginAction extends ActionSupport implements ServletRequestAware


private HttpServletRequest request;

//需實現方法 public void setServletRequest(HttpServletRequest request) { this.request=request; } //response示例

public String execute1() throws IOException {
		if ("ping".equals(username)) {
			response.setContentType("text/html;charset=utf-8");   
			PrintWriter out = response.getWriter();   
			out.print("<script type='text/javascript'>alert('驗證碼輸入錯誤!')</script>");   
			out.print("<script type='text/javascript'>location.href='/index.jsp'</script>");   
			out.flush();   
			out.close();  
		} else {
			response.setContentType("text/html;charset=utf-8");   
			PrintWriter out = response.getWriter();   
			out.print("<script type='text/javascript'>alert('驗證碼輸入錯誤!')</script>");   
			out.flush();   
			out.close();  
		}
		System.out.println(username);
		return SUCCESS;
	}

第三種：ServletActionContext（第二選擇）

public String execute2() throws IOException {
		if ("ping".equals(username)) { 
			ServletActionContext.getResponse();
			ServletActionContext.getRequest();
			ServletActionContext.getRequest().getSession();
			ServletActionContext.getServletContext();
		} else {
			
		}
		System.out.println(username);
		return SUCCESS;
	}

第四種：XXXAware接口（相似於第一種）

public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware {
	
	private Map<String, Object> request;
	private Map<String, Object> session;
	private Map<String, Object> application;
	
	//DI dependency injection
	//IoC inverse of control
	public String execute() {
		request.put("r1", "r1");
		session.put("s1", "s1");
		application.put("a1", "a1");
		return SUCCESS; 
	}

	@Override
	public void setRequest(Map<String, Object> request) {
		this.request = request;
	}

	@Override
	public void setSession(Map<String, Object> session) {
		this.session = session;
	}

	@Override
	public void setApplication(Map<String, Object> application) {
		this.application = application;
	}
	
	
}