报错内容：

java.lang.IllegalStateException: Async support must be enabled on a servlet and for all filters involved in async request processing. This is done in Java code using the Servlet API or by adding "true" to servlet and filter declarations in web.xml.

解决方法：

需要在web.xml 的filter 和DispatcherServlet 中配置  

<async-supported>true</async-supported>

官网地址：https://docs.spring.io/spring-framework/reference/web/webmvc/mvc-ann-async.html

如下：

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
 3          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd
 4 http://xmlns.jcp.org/xml/ns/javaee " version="4.0">
 5     <filter>
 6         <filter-name>CharacterEncodingFilter</filter-name>
 7         <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
 8         <async-supported>true</async-supported>
 9         <init-param>
10             <param-name>encoding</param-name>
11             <param-value>utf-8</param-value>
12         </init-param>
13     </filter>
14     <filter-mapping>
15         <filter-name>CharacterEncodingFilter</filter-name>
16         <url-pattern>/*</url-pattern>
17     </filter-mapping>
18     <context-param>
19         <param-name>contextConfigLocation</param-name>
20         <param-value>classpath:spring.xml,classpath:shiro.xml,classpath:task.xml</param-value>
21     </context-param>
22     <listener>
23         <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
24     </listener>
25     <servlet>
26         <servlet-name>springDispatcherServlet</servlet-name>
27         <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
28         <async-supported>true</async-supported>
29         <init-param>
30             <param-name>contextConfigLocation</param-name>
31             <param-value>classpath:springmvc.xml</param-value>
32         </init-param>
33         <load-on-startup>1</load-on-startup>
34     </servlet>
35     <servlet-mapping>
36         <servlet-name>springDispatcherServlet</servlet-name>
37         <url-pattern>/</url-pattern>
38     </servlet-mapping>
39     <!-- 404错误 -->
40     <error-page>
41         <error-code>404</error-code>
42         <location>/404.jsp</location>
43     </error-page>
44 
45     <filter>
46         <filter-name>HiddenHttpMethodFilter</filter-name>
47         <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
48         <async-supported>true</async-supported>
49     </filter>
50     <filter-mapping>
51         <filter-name>HiddenHttpMethodFilter</filter-name>
52         <url-pattern>/*</url-pattern>
53     </filter-mapping>
54     <!-- 添加日志监听器 -->
55     <context-param>
56         <param-name>logbackConfigLocation</param-name>
57         <param-value>classpath:logback.xml</param-value>
58     </context-param>
59     <listener>
60         <listener-class>ch.qos.logback.ext.spring.web.LogbackConfigListener</listener-class>
61     </listener>
62     <!-- shiro 配置 start-->
63     <filter>
64         <filter-name>shiroFilter</filter-name>
65         <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
66         <async-supported>true</async-supported>
67         <init-param>
68             <param-name>targetFilterLifecycle</param-name>
69             <param-value>true</param-value>
70         </init-param>
71     </filter>
72 
73     <filter-mapping>
74         <filter-name>shiroFilter</filter-name>
75         <url-pattern>/*</url-pattern>
76     </filter-mapping>
77     <!-- shiro 配置 end-->
78 
79 
80 </web-app>