如何处理Google App Engine中的会话？

Question

我在servlet中成功创建了会话,我可以获得jsp的会话/会话属性,但不能在端点类中获取.我想在端点类中获取会话信息.请帮我解决一下这个.

我在eclipse中使用maven,我在appengine-web.xml中启用了会话

我读了一篇关于这个的文章,除了如何启用会话我什么都不懂.

该servlet用于检查是否已存在会话

public class FirstServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public FirstServlet () {
    super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    service(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    service(request, response);
}
@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.setContentType("text/html");
    HttpSession session=request.getSession(false);
    if (session != null) {
        String name = session.getAttribute("name");
        // do something
    } else {
        // do something
    }

}
}

如果没有session,则使用此servlet创建会话

public class SeccondServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public SeccondServlet() {
    super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    service(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    service(request, response);
}

@Override

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    response.setContentType("text/html");
    request.getRequestDispatcher("login.html").include(request, response);  
    String name = request.getParameter("name"); 
    HttpSession session=request.getSession();
    session.setAttribute("name", name);
    // do something 
}
}

这是我的端点api类(Google Cloud Endpoints)

@Api(
    name = "myapi",
    version = "v1",
    clientIds = "given client ids")
public class MyApi{
    @ApiMethod(name = "name", path = "name", httpMethod = "post")
    public List<String> getUser( HttpServletRequest servletReq) {
        HttpSession session = servletReq.getSession(false);
        List<String> name= new ArrayList<String>();
        if(session == null) {
            userName.add("no Name");
        } else {
            name.add((String)session.getAttribute("name"));
        }

       return name;
    }

我仍然得到"没有名字"的结果,即使我创建了会话,我可以得到会话属性,这里"名称"

Answer 1

假设您了解HttpSessions(如果不是,它只是在服务器和客户端之间交换cookie以便处理登录用户)

因此,所有与用户相关或任何其他与会话相关的信息都存储在服务器端,并且表示信息的会话Id将作为cookie发送到客户端,并且客户端将在每个http请求上将其发回.

AppEngine使用数据存储来存储会话信息和内存缓存,以便更快地访问

您可以使用在每个http请求中注入的标准HttpSession对象来访问会话数据

访问此HttpSession的代码在您使用的框架中有所不同,如果您希望我可以使用特定的代码片段来帮助更好地理解它

更新:

如果您正在使用servlet,那么访问会话将如下所示

public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private final String userID = "Pankaj";
private final String password = "journaldev";

protected void doPost(HttpServletRequest request,
        HttpServletResponse response) {
  HttpSession session=request.getSession();
  // access any value
  User user = (User)session.getAttribute("loggedInUser");
}

谷歌云终端使用它如下所示

@ApiMethod
public Response getUser( HttpServletRequest servletReq) {
    HttpSession session = servletReq.getSession();
    session.getAttribute("loggedInUser");
}