必须在servlet和异步请求处理中涉及的所有筛选器上启用异步支持

<servlet>
    <servlet-name>MyServlet</servlet-name>
    <servlet-class>com.example.MyServlet</servlet-class>
    <async-supported>true</async-supported>
</servlet>

@WebServlet("/myServlet")
public class MyServlet extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        AsyncContext asyncContext = request.startAsync();
        asyncContext.addListener(new MyAsyncListener());
        asyncContext.start(new MyAsyncTask(asyncContext));
    }
}

public class MyAsyncTask implements Runnable {
    private AsyncContext asyncContext;
    
    public MyAsyncTask(AsyncContext asyncContext) {
        this.asyncContext = asyncContext;
    }
    
    public void run() {
        // 异步处理任务，例如数据库查询、网络请求等
        // ...
        
        // 处理完成后通知服务器
        asyncContext.complete();
    }
}

@WebFilter("/myServlet")
public class MyFilter implements Filter {
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        HttpServletResponse httpResponse = (HttpServletResponse) response;
        
        // 对请求进行预处理，例如身份验证、参数校验等
        
        AsyncContext asyncContext = httpRequest.startAsync();
        asyncContext.addListener(new MyAsyncListener());
        asyncContext.start(new MyAsyncTask(asyncContext));
        
        // 对响应进行后处理，例如设置响应头、日志记录等
        
        chain.doFilter(request, response);
    }
}