geoserver + openlayers 跨域问题解决

用Openlayers访问GeoServer发布的矢量切片是，出现跨域访问问题，即 CORS 头缺少 'Access-Control-Allow-Origin'
本人使用环境的版本是：GeoServer 2.18.1，OpenLayers 6.4.3
解决方法如下：
1.下载 cors-filter.jar 和 java-property-utils.jar，地址如下
https://mvnrepository.com/artifact/com.thetransactioncompany/cors-filter/2.9.1
https://mvnrepository.com/artifact/com.thetransactioncompany/java-property-utils/1.16
2.将下载的两个 jar包 拷贝至 tomcat 的安装路径下的 lib文件夹中，如：D:...apache-tomcat-9.0.41lib
3.添加 tomcat 的 web.xml 文件内容，路径为：D:...apache-tomcat-9.0.41confweb.xml
在 web.xml文件中定位到下面内容，

<welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>

在定位内容的前面，添加下面的补充内容：

<filter>
        <filter-name>CORS</filter-name>
        <filter-class>com.thetransactioncompany.cors.CORSFilter</filter-class>
        <init-param>
            <param-name>cors.allowOrigin</param-name>
            <param-value>*</param-value>
        </init-param>
        <init-param>
            <param-name>cors.supportedMethods</param-name>
            <param-value>GET, POST, HEAD, PUT, DELETE</param-value>
        </init-param>
        <init-param>
            <param-name>cors.supportedHeaders</param-name>
            <param-value>Accept, Origin, X-Requested-With, Content-Type, Last-Modified</param-value>
        </init-param>
        <init-param>
            <param-name>cors.exposedHeaders</param-name>
            <param-value>Set-Cookie</param-value>
        </init-param>
        <init-param>
            <param-name>cors.supportsCredentials</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CORS</filter-name>
        <url-pattern>/*</url-pattern>
   </filter-mapping>

4.重启 tomcat，解决问题