Our Spring Configuration created a Spring Bean named springSessionRepositoryFilter that implements Filter. The springSessionRepositoryFilter bean is responsible for replacing the HttpSession with a custom implementation that is backed by Spring Session.

我们的Spring配置创建了一个名为springSessionRepositoryFilter的Spring Bean，它实现了Filter。

springSessionRepositoryFilter bean负责将HttpSession替换为由Spring Session会话支持的自定义实现。

In order for our Filter to do its magic, Spring needs to load our Config class. Last, we need to ensure that our Servlet Container (that is, Tomcat) uses our springSessionRepositoryFilter for every request. Fortunately, Spring Session provides a utility class named AbstractHttpSessionApplicationInitializer to make both of these steps easy. The following shows an example:

为了让过滤器发挥作用，Spring需要加载配置类。最后，我们需要确保Servlet容器(即Tomcat)对每个请求都使用springSessionRepositoryFilter。幸运的是，Spring Session提供了一个名为AbstractHttpSessionApplicationInitializer的实用工具类，可以简化这两个步骤。以下是一个例子:

You can run the sample by obtaining the source code and invoking the following command:
您可以通过获得源代码并调用以下命令来运行示例:

$ ./gradlew :spring-session-sample-javaconfig-redis:tomcatRun

For the sample to work, you must install Redis 2.8+ on localhost and run it with the default port (6379). Alternatively, you can update the RedisConnectionFactory to point to a Redis server. Another option is to use Docker to run Redis on localhost. See Docker Redis repository for detailed instructions.

要使样例工作，您必须在本地主机上安装Redis 2.8+，并使用默认端口(6379)运行它。或者，您可以更新RedisConnectionFactory以指向一个Redis服务器。另一个选项是使用Docker在本地主机上运行Redis。详细说明请参阅Docker Redis知识库。

You should now be able to access the application at http://localhost:8080/

现在，您应该能够通过http://localhost:8080/访问该应用程序

4.2. Exploring the httpsession Sample Application(探索httpsession示例应用程序)

Now you can try to use the application. To do so, fill out the form with the following information:

现在您可以尝试使用该应用程序。为此，请填写以下资料:

• Attribute Name: username

• Attribute Value: rob

 Now click the Set Attribute button. You should now see the values displayed in the table.

 现在单击Set属性按钮。现在应该可以看到表中显示的值。

4.3. How Does It Work?

We interact with the standard HttpSession in the SessionServlet shown in the following listing:

我们与SessionServlet中的标准HttpSession进行交互，如下面的清单所示:

src/main/java/sample/SessionServlet.java

@WebServlet("/session")
public class SessionServlet extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        String attributeName = req.getParameter("attributeName");
        String attributeValue = req.getParameter("attributeValue");
        req.getSession().setAttribute(attributeName, attributeValue);
        resp.sendRedirect(req.getContextPath() + "/");
    }

    private static final long serialVersionUID = 2878267318695777395L;

}

Instead of using Tomcat’s HttpSession, we persist the values in Redis. Spring Session creates a cookie named SESSION in your browser. That cookie contains the ID of your session. You can view the cookies (with Chrome or Firefox).

我们没有使用Tomcat的HttpSession，而是将这些值保存在Redis中。Spring Session在浏览器中创建一个名为Session的cookie。该cookie包含会话的ID。您可以查看cookies(使用Chrome或Firefox)。

You can remove the session by using redis-cli. For example, on a Linux based system you can type the following:

您可以使用redis-cli删除会话。例如，在基于Linux的系统上，您可以输入以下内容:

$ redis-cli keys ‘*‘ | xargs redis-cli del

The Redis documentation has instructions for installing redis-cli.

Redis文档中有安装Redis -cli的说明。

Alternatively, you can also delete the explicit key.

Enter the following into your terminal, being sure to replace 7e8383a4-082c-4ffe-a4bc-c40fd3363c5e with the value of your SESSION cookie:

或者，您也可以删除显式密钥。

在您的终端中输入以下内容，请确保使用您的会话cookie的值替换7e8383a4-082c-4ffe-a4bc-c40fd3363c5e:

$ redis-cli del spring:session:sessions:7e8383a4-082c-4ffe-a4bc-c40fd3363c5e

Now you can visit the application at http://localhost:8080/ and see that the attribute we added is no longer displayed.

 现在，您可以通过http://localhost:8080/访问该应用程序，并看到我们添加的属性不再显示。