tomcat跨域（亲测可用）

首先下载cors-filter-2.5.jar（版本不要求）和java-property-utils-1.9.1
1、把这两个jar包放在tomcat的lib下。
2、在conf文件夹下找到web.xml。
3、在web.xml中添加如下代码：

<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>