CORS解决跨域访问问题

简言之，CORS就是为了让AJAX可以实现可控的跨域访问而生的。

Tomcat下的配置
   下载cors-filter-1.7.jar，java-property-utils-1.9.jar这两个库文件，放到lib目录下。（可在
http://search.maven.org上查询并下载。）工程项目（如：geoserver）中web.xml中的配置如下：

 <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>