ajax请求 statue code =200 ，但是进了error。
控制台会有报错
Failed to load No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://10.10.10.50:8080' is therefore not allowed access.
服务器没有加上 Access-Control-Allow-Origin ，因为在本地服务器调试，跨域了。后来在线调试，ok。