不。servlet不是线程安全的

这允许一次访问多个线程

如果你想让它成为线程安全的Servlet，你可以去

实现SingleThreadInterface(我) 哪个是空白界面有没有

方法

或者我们可以使用同步方法

利用synchronized可以使整个服务方法实现同步化

关键字前面的方法

例如::

public Synchronized class service(ServletRequest request,ServletResponse response)throws ServletException,IOException

或者我们可以把代码的put块放在Synchronized块中

例如::

Synchronized(Object)

{

----Instructions-----

}

我觉得Synchronized块比整个方法更好

同步

Session in Java servlets is the same as session in other languages such as PHP. It is unique to the user. The server can keep track of it in different ways such as cookies, url rewriting etc. This Java doc article explains it in the context of Java servlets and indicates that exactly how session is maintained is an implementation detail left to the designers of the server. The specification only stipulates that it must be maintained as unique to a user across multiple connections to the server. Check out this article from Oracle for more information about both of your questions.

这里有一个关于如何在servlet中使用session的优秀教程。这里有来自Sun的一章关于Java servlet，它们是什么以及如何使用它们。在这两篇文章之间，你应该能够回答你所有的问题。

Servlet规范JSR-315明确定义了服务(以及doGet、doPost、doPut等)方法中的web容器行为(2.3.3.1多线程问题，第9页):

A servlet container may send concurrent requests through the service method of the servlet. To handle the requests, the Servlet Developer must make adequate provisions for concurrent processing with multiple threads in the service method. Although it is not recommended, an alternative for the Developer is to implement the SingleThreadModel interface which requires the container to guarantee that there is only one request thread at a time in the service method. A servlet container may satisfy this requirement by serializing requests on a servlet, or by maintaining a pool of servlet instances. If the servlet is part of a Web application that has been marked as distributable, the container may maintain a pool of servlet instances in each JVM that the application is distributed across. For servlets not implementing the SingleThreadModel interface, if the service method (or methods such as doGet or doPost which are dispatched to the service method of the HttpServlet abstract class) has been defined with the synchronized keyword, the servlet container cannot use the instance pool approach, but must serialize requests through it. It is strongly recommended that Developers not synchronize the service method (or methods dispatched to it) in these circumstances because of detrimental effects on performance

从上面的解释可以清楚地看出，通过实现SingleThreadModel, servlet容器可以确保servlet的线程安全。容器实现可以通过两种方式做到这一点:

1)序列化请求(排队)到单个实例——这类似于servlet不实现SingleThreadModel，但同步service/ doXXX方法;或

2)创建一个实例池——这是一个更好的选择，可以在servlet的启动/初始化工作/时间与托管servlet的环境的限制性参数(内存/ CPU时间)之间进行权衡。

不。servlet不是线程安全的

这允许一次访问多个线程

如果你想让它成为线程安全的Servlet，你可以去

实现SingleThreadInterface(我) 哪个是空白界面有没有

方法

或者我们可以使用同步方法

利用synchronized可以使整个服务方法实现同步化

关键字前面的方法

例如::

public Synchronized class service(ServletRequest request,ServletResponse response)throws ServletException,IOException

或者我们可以把代码的put块放在Synchronized块中

例如::

Synchronized(Object)

{

----Instructions-----

}

我觉得Synchronized块比整个方法更好

同步

塞申斯是克里斯·汤普森说的。

实例化——当容器接收到第一个映射到servlet的请求时，servlet被实例化(除非servlet被配置为在web.xml中使用<load-on-startup>元素在启动时加载)。使用相同的实例为后续请求提供服务。