3 front-end frame Built environment, suddenly error "WebSocket is closed before the connection is established. "The program cannot run and the WebSocket connection failed. This problem is only created in Google Chrome, but not in Firefox.
The reason is that in the web.xml I have added to solve the Chinese problem
<filter>
<filter-name>encodingFilter</filter-name>
<filter-class> org.springframework.web.filter.characterencodingfilter</filter-class>
<span style= "color: #FF0000;" ><async-supported>true</async-supported></span>
<init-param>
<param-name >encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
The red part is not added by me. It turns out that if you add it, you won't be able to report the above error. Hope to be helpful to everyone.