跨域请求设置

参考博客：

https://my.oschina.net/wangnian/blog/689020

https://blog.csdn.net/java_green_hand0909/article/details/78740765

　　　　　// 接受任意域名的请求
        response.setHeader("Access-Control-Allow-Origin", "*"); 
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS");  
        response.setHeader("Access-Control-Allow-Headers", "*");  
        // 表示是否允许发送Cookie,默认情况下，Cookie不包括在CORS请求之中
        response.setHeader("Access-Control-Allow-Credentials", "true");  
        // 指定本次预检请求的有效期，单位为秒
        response.setHeader("Access-Control-Max-Age", "1728000");

W3C: https://www.w3.org/wiki/CORS_Enabled#What_is_CORS_about.3F