Struts2与Servlet解耦

最新推荐文章于 2020-07-30 14:32:35 发布

原创最新推荐文章于 2020-07-30 14:32:35 发布 · 1k 阅读

0 ·

CC 4.0 BY-SA版权

Struts 专栏收录该内容

19 篇文章

订阅专栏

本文详细介绍了Struts2如何通过封装HttpServletRequest、HttpSession和ServletContext对象，避免与ServletAPI耦合，方便Action进行单元测试。具体包括通过ServletActionContext类直接获取这些对象，以及实现特定接口由Struts框架运行时注入。此外，还展示了如何访问request、session、application对象中的属性，并提供了JSP页面展示实例。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

与Servlet API解耦的访问方式

为了避免与 Servlet API 耦合在一起, 方便 Action 做单元测试,Struts2 对 HttpServletRequest, HttpSession和 ServletContext进行了封装, 构造了 3 个 Map 对象来替代这 3 个对象, 在 Action 中可以直接使用 HttpServletRequest, HttpSession, ServletContext对应的 Map 对象来保存和读取数据.

访问request/session/application对象

方法一:通过ServletActionContext类直接获取

ActionContext是Action 执行的上下文对象, 在ActionContext中保存了Action 执行所需要的所有对象, 包括parameters, request, session,application 等.

获取HttpServletRequest对应的Map 对象:

public Object get(Object key): ActionContext类中没有提供类似getRequest() 这样的方法来获取HttpServletRequest对应的Map 对象. 要得到HttpServletRequest对应的Map 对象, 可以通过为 get() 方法传递 “request” 参数实现

获取HttpSession对应的Map 对象:

public Map getSession()

获取ServletContext对应的Map 对象:

public Map getApplication()

publicString test(){

HttpServletRequestrequest=ServletActionContext.getRequest();

HttpServletResponse response=ServletActionContext.getResponse();

HttpSession session=request.getSession();

ServletContextservletContext=ServletActionContext.getServletContext();

return"success";

}

如果你只是想访问session的属性（Attribute），

你也可以通过ActionContext.getContext().getSession()获取

	@Override
	public String execute() throws Exception {
		HttpServletRequest request=ServletActionContext.getRequest();
		HttpServletResponse response=ServletActionContext.getResponse();
		Map  sessionMap=ServletActionContext.getContext().getSession();
		ServletContext sc=ServletActionContext.getServletContext();
		request.setAttribute("username", "username_request");
		sessionMap.put("username", "username_session");
		sc.setAttribute("username", "username_application");
		System.err.println("ssssssssssss");
		return "attr";
	}

方法二:实现指定接口，由struts框架运行时注入：

Action类通过可以实现某些特定的接口, 让Struts2 框架在运行时向 Action 实例注入parameters, request, session 和 application 对应的 Map 对象:

importorg.apache.struts2.interceptor.ServletRequestAware;

importorg.apache.struts2.interceptor.ServletResponseAware;

importorg.apache.struts2.interceptor.SessionAware;

importorg.apache.struts2.util.ServletContextAware;

publicclass ContextAction02 extendsActionSupport implementsServletRequestAware,

ServletResponseAware,ServletContextAware,SessionAware {

privateHttpServletRequestrequest;

privateServletContextservletContext;

privateHttpServletResponseresponse;

privateMap<String, Object> session;

publicString test(){

System.out.println(" request "+request);

System.out.println(" servletContext "+servletContext);

System.out.println(" response "+response);

System.out.println(" session "+session);

return "success"; }

publicvoidsetServletRequest(HttpServletRequest request) {

this.request=request;}

publicvoidsetServletResponse(HttpServletResponse response) {

this.response=response;}

publicvoidsetServletContext(ServletContext context) {

this.servletContext=context;}

publicvoidsetSession(Map<String, Object> session){

this.session=session;}

}

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;
		
	}
	
}