来自HttpSessionListener的sessionCreated()是否自动与request.getSession()同步? [英] Is sessionCreated() from a HttpSessionListener automatically synchronized with request.getSession()?

问题描述

HttpSessionListener中的sessionCreated()方法是否自动与request.getSession()调用同步?特别是，我想知道在sessionCreated()方法中设置会话属性并在servlet中使用request.getSession().getAttribute("something")检索属性是否是线程安全的?
例如，拥有

Is sessionCreated() method from a HttpSessionListener automatically synchronized with request.getSession() call? In particular, I would like to know if it is thread safe to set a session attribute in the sessionCreated() method and retrieve the attribute with request.getSession().getAttribute("something") in a servlet?
For example, is it thread-safe to have

@Override
public void sessionCreated(HttpSessionEvent se) {
  se.getSession().setAttribute("something", new Something());
}

在HttpSessionListener中，并且拥有

Something something = (Something) request.getSession().getAttribute("something");
synchronized(something){
  // do anything with this "something" object
}

在HttpServlet?的doGet()方法内部的

我要关注的是，如果该sessionCreated()方法没有自动与requested.getSession()同步，则getAttribute("something")返回的值可以是null. /p>

inside of a doGet() method of a HttpServlet? The point of my concern is that if this sessionCreated() method is not automatically synchronized with requested.getSession() the value returned by getAttribute("something") can be null.

推荐答案

这两个方法调用至少在Tomcat中在同一线程中执行.我使用log4j通过打印线程ID对其进行了检查.因此，至少在Tomcat中，上述方法调用的组合是线程安全的.

These two method calls are executed in the same thread, at least in Tomcat. I checked it with printing thread IDs using log4j. Therefore, the combination of the method calls, described above, is thread-safe, at least in Tomcat.

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