java.lang.IllegalStateException:

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 "<async-supported>true</async-supported>" to servlet and filter declarations in web.xml.
    at org.springframework.util.Assert.state(Assert.java:385) ~[spring-core-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.context.request.async.StandardServletAsyncWebRequest.startAsync(StandardServletAsyncWebRequest.java:103) ~[spring-web-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.context.request.async.WebAsyncManager.startAsyncProcessing(WebAsyncManager.java:422) ~[spring-web-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.context.request.async.WebAsyncManager.startDeferredResultProcessing(WebAsyncManager.java:402) ~[spring-web-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.DeferredResultMethodReturnValueHandler.handleReturnValue(DeferredResultMethodReturnValueHandler.java:49) ~[spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:71) ~[spring-web-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:126) ~[spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:777) ~[spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:706) ~[spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943) [spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877) [spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) [spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857) [spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) [servlet-api.jar:na]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) [spring-webmvc-4.1.5.RELEASE.jar:4.1.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [servlet-api.jar:na]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) [catalina.jar:8.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.33]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-websocket.jar:8.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.33]
    at com.wisely.highlight_springmvc4.web.ch4_5.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:29) [classes/:na]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) [catalina.jar:8.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) [catalina.jar:8.0.33]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) [catalina.jar:8.0.33]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) [catalina.jar:8.0.33]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) [catalina.jar:8.0.33]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) [catalina.jar:8.0.33]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [catalina.jar:8.0.33]
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616) [catalina.jar:8.0.33]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) [catalina.jar:8.0.33]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522) [catalina.jar:8.0.33]
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095) [tomcat-coyote.jar:8.0.33]
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672) [tomcat-coyote.jar:8.0.33]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1502) [tomcat-coyote.jar:8.0.33]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1458) [tomcat-coyote.jar:8.0.33]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_91]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_91]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-util.jar:8.0.33]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_91]

错误提示中已经写的很清楚了(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 "<async-supported>true</async-supported>" to servlet and filter declarations in web.xml.),需要在 web.xml 文件中的 filter 和 servlet 定义中添加："<async-supported>true</async-supported>"。
1.如果使用@WebServlet来标注，则可以设定其asyncSupported为true 。 例如：

@WebServlet(urlPatterns = "/some.do", asyncSupported = true )   
public class AsyncServlet extends HttpServlet 

2.如果使用web.xml设定Servlet，则可以设定标签为true ：

<servlet>   
<servlet-name>AsyncServlet</servlet-name>   
<servlet-class>com.pkgname.AsyncServlet</servlet-class>   
<async-supported>true</async-supported>   
</servlet>   

3.若其前端有过滤器，则过滤器亦需标示其支援异步处理，如果使用@WebFilter ，同样是可以设定其asyncSupported为true 。 例如：

@WebFilter(urlPatterns = "/some.do", asyncSupported = true )   
public class AsyncFilter implements Filter{ 

4.如果使用web.xml设定过滤器，则可以设定标签为true ：

<filter>   
< filter -name>AsyncFilter</ filter -name>   
< filter -class>com.pkgname.AsyncFilter</ filter -class>   
<async-supported>true</async-supported>   
</ filter >