tomcat配置cors实现跨域

<!--
	Enable CORS on Tomcat : Place under ${tomcat_home}/conf/web.xml
	See http://enable-cors.org/server_tomcat.html and http://tomcat.apache.org/tomcat-7.0-doc/config/filter.html#CORS_Filter
	-->
	<!-- ================== CUSTOM Filter Definitions ===================== -->
	<filter>
	<filter-name>CorsFilter</filter-name>
	<filter-class>org.apache.catalina.filters.CorsFilter</filter-class>
	<init-param>
	<param-name>cors.allowed.origins</param-name>
	<param-value>*</param-value>
	</init-param>
	<init-param>
	<param-name>cors.allowed.methods</param-name>
	<param-value>GET,POST,HEAD,OPTIONS,PUT</param-value>
	</init-param>
	<init-param>
	<param-name>cors.allowed.headers</param-name>
	<param-value>Content-Type,X-Requested-With,accept,Origin,Access-Control-Request-Method,Access-Control-Request-Headers</param-value>
	</init-param>
	<init-param>
	<param-name>cors.exposed.headers</param-name>
	<param-value>Access-Control-Allow-Origin,Access-Control-Allow-Credentials</param-value>
	</init-param>
	<init-param>
	<param-name>cors.support.credentials</param-name>
	<param-value>true</param-value>
	</init-param>
	<init-param>
	<param-name>cors.preflight.maxage</param-name>
	<param-value>10</param-value>
	</init-param>
	</filter>
	<filter-mapping>
	<filter-name>CorsFilter</filter-name>
	<url-pattern>/*</url-pattern>
	</filter-mapping> 此方适用tomcat下的所有项目，如果需要单个项目请配置在项目的web.xml下面，并导入相应的包