Google App Engine Cloud中会重置最终的静态变量(final static variables are reset in Google App Engine Cloud)

 我有一个GWT + GAE网络应用程序，有几个服务和模块。 我正在使用mvp4g的模块功能。 我所有的服务扩展到： 
 
public abstract class BaseServiceImpl extends RemoteServiceServlet {
 protected final static Map USERS = new HashMap();
 
 我使用USERS来存储我当前的活动用户会话。 一旦我用户认证自己，我将他的会话ID存储为地图的关键字。 
 
protected String getSessionId() {
    return getThreadLocalRequest().getSession().getId();
}

public String authenticate(String username, String password) {
    ...
    ..
    .
   String id = getSessionId();
   synchronized( this ) {    
       users.put(id, user);
   } 
   ...
   ..
   .
 
 对于每个请求，我检查用户会话是否仍然有效。 
 
protected boolean validUserSession() {  
    if(getThreadLocalRequest() == null) {
     logger.log(Level.SEVERE, "Thread is null");
     return false;
 } else if(getThreadLocalRequest().getSession() == null) {
     logger.log(Level.SEVERE, "Session is null");
     return false;
 }
 String id = getSessionId();
 UserJDO user = (UserJDO) users.get(id);
 if(user==null) {   
     logger.log(Level.SEVERE, "User is null");
     return false;
 }
 return true;
}
 
 我启用了会话。 接下来我发布appengine-web.xml的最后几行 
 
...
..
.
<sessions-enabled>true</sessions-enabled>
</appengine-web-app>
 
 在开发服务器中一切正常。 但是，当我将它部署到谷歌应用引擎云时， 用户变量会针对每个请求进行重置。 
 
 任何人都可以解释我发生了什么？ 我应该如何继续？ 我应该将用户会话存储在数据存储中吗？ 

I have a GWT+GAE web app with several service and modules. I am using the module functionlity of mvp4g. All of my services extends: 
 
public abstract class BaseServiceImpl extends RemoteServiceServlet {
 protected final static Map USERS = new HashMap();
 
I use USERS to store my current active user sessions. Once I user authenticates himself I store his session id as a key of the map. 
 
protected String getSessionId() {
    return getThreadLocalRequest().getSession().getId();
}

public String authenticate(String username, String password) {
    ...
    ..
    .
   String id = getSessionId();
   synchronized( this ) {    
       users.put(id, user);
   } 
   ...
   ..
   .
 
For every request, I check if the user session is still valid.
 
protected boolean validUserSession() {  
    if(getThreadLocalRequest() == null) {
     logger.log(Level.SEVERE, "Thread is null");
     return false;
 } else if(getThreadLocalRequest().getSession() == null) {
     logger.log(Level.SEVERE, "Session is null");
     return false;
 }
 String id = getSessionId();
 UserJDO user = (UserJDO) users.get(id);
 if(user==null) {   
     logger.log(Level.SEVERE, "User is null");
     return false;
 }
 return true;
}
 
I have sessions enabled. Next I post the last lines of appengine-web.xml 
 
...
..
.
<sessions-enabled>true</sessions-enabled>
</appengine-web-app>
 
Everything works fine in the Development server. However, when I deploy it to the google app engine cloud the users variable is reset for every request.
 
Can anyone explain me what it is happening? How should I proceed? Should I store the user sessions in the datastore?

原文：https://stackoverflow.com/questions/3545554