AJax+Servlet 跨域問題 Access-Control-Allow-Origin

解決報錯
XMLHttpRequest cannot load http://192.168.31.151/smartcity/add.PHP. No ‘Access-Control-Allow-Origin’ header is present on the requested resource. Origin ‘http://localhost:8156’ is therefore not allowed access.

在 Servlet 的頭部加上

response.setHeader(“Access-Control-Allow-Origin”, “*”);

如果你不想所有請求到此 Servlet 的 request 都通過 , 可以改爲
response.setHeader(“Access-Control-Allow-Origin”, “yoururl”);