servlet会话由cookie支持。您基本上需要从第一个请求的响应中获取所有 Set-Cookie 标头，然后传递 name = value 成对后续请求的 Cookie 标头。

The servlet session is backed by a cookie. You basically need to grab all Set-Cookie headers from the response of the first request and then pass the name=value pairs back as Cookie header of the subsequent requests.

目前还不清楚您使用的是哪个HTTP客户端，但是如果它的 java.net.URLConnection ，然后你可以使用 java.net.CookieHandler 。

It's unclear what HTTP client you're using, but if it's java.net.URLConnection, then you could use the java.net.CookieHandler for this.

// First set the default cookie manager.
CookieHandler.setDefault(new CookieManager(null, CookiePolicy.ACCEPT_ALL));

// All the following subsequent URLConnections will use the same cookie manager.
URLConnection connection = new URL(url).openConnection();
// ...

connection = new URL(url).openConnection();
// ...

connection = new URL(url).openConnection();
// ...

参见：

• 使用java.net.URLConnection来触发和处理HTTP请求 - 维护会话


• servlet如何工作？实例化，会话，共享变量和多线程



See also:

• Using java.net.URLConnection to fire and handle HTTP requests - Maintaining the session
• How do servlets work? Instantiation, sessions, shared variables and multithreading