Struts2学习笔记（8）--Struts2和Servlet 耦合

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   Struts2 和 Servlet 耦合
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首选 ActionConext 其次 ServletActionContext 最后是实现接口

-- 1 --
 ### ActionContext ###  --- 不能获得response对象

static ActionContext getContext()   获得当前线程的向下文
                           
                                    相当于
Object get(Object key)               ---- getAttribute()

void put( Object key, Object value ) ---- setAttribute()

Map getParameter()    相当于Servlet中的getParameterMap()

Map getApplication()   对应于ServletContext

如:

action中
ActionContext.getContext().put("zhangsan","hello");

jsp中
张三：${ requestScope.zhangsan }

 

-- 2 --
通过接口使用 --- 典型的依赖注入

### ServletContextAware ### 接口

void setServletContext( ServletContext )

### ServletRequestAware ### 接口

void setServletRequest( HttpServletRequest )

### ServletResponseAware ### 接口

void setServletResponse( HttpServletResponse )

例：
public class LoginAction extends ActionSupport
 implements ServletRequestAware,
  ServletResponseAware {

 private String username;
 private String password;
 //setter...getter...

 private HttpServletRequest request;
 private HttpServletResponse response;

 public String execute() throws Exception {

  //使用request对象 
  request.setAttribute("zhangshan","hello");

  //使用response对象
  Cookie cookie = new Cookie("username",
      this.getUsername());
  cookie.setMaxAge(1000);
  response.addCookie(cookie);

  return "success";
 }

 //这个方法由Strust2框架来自动调用
 //调用后，便可以使用容器的request对象了
 public void setServletRequest(HttpServletRequest request) {

  this.request = request;
 }

 public void setServletResponse(HttpServletResponse responset) {

  this.response = response;
 }
}

---------------------
jsp页面中显示cookie

 cookie: ${ cookie.username.value }

--------------------

-- 3 --

使用 org.apache.struts2.ServletActionContext类
---继承于 com.opensymphony.xwork2.ActionContext

内部全部为static的方法

static ActionContext getActionContext(HttpServletRequest req)

static PageContext getPageContext() 

static HttpServletRequest getRequest()
 
static HttpServletResponse getResponse() 

static ServletContext getServletContext() 

static ValueStack getValueStack(HttpServletRequest req) 

-----

static void setRequest(HttpServletRequest request)

static void setResponse(HttpServletResponse response)

static void setServletContext(ServletContext servletContext)

 

例：
public class LoginAction extends ActionSupport {

 private String username;
 private String password;
 //setter...getter...

 

 public String execute() throws Exception {

  HttpServletResponse response = ServletActionContext.getResponse();
  HttpServletRequest request = ServletActionContext.getRequest();
  HttpSession session = request.getSession();

  return "success";
 }
}