Front-and-back interaction to resolve Cross-domain request issues _ cross-domain request

The separation and development of the front and back ends often involve the separation and development of the front and rear ends.

However, JS prohibits cross-domain requests. For example, Ajax requests in api.test.com such as access to aaa.test.com servers

Then the front and rear end have to take some measures to solve

Back-End (Java):

Set the response header in the Interceptor or filter, take the interceptor in SPRINGMVC for example:

Package cn.creat.zhxy.interceptor;


Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;


Import Org.springframework.web.servlet.HandlerInterceptor;
Import Org.springframework.web.servlet.ModelAndView;

public class Alloworigininterceptor implements handlerinterceptor{


@Override
public void Aftercompletion (HttpServletRequest request,
HttpServletResponse Res, Object arg2, Exception arg3)
Throws Exception {

}


@Override
public void Posthandle (HttpServletRequest arg0, HttpServletResponse arg1,
Object arg2, Modelandview arg3) throws Exception {
}


@Override
public boolean prehandle (HttpServletRequest request, HttpServletResponse Res,
Object arg2) throws Exception {
Res.setheader ("Access-control-allow-origin", Request.getheader ("Origin"));
Res.setheader ("Access-control-allow-methods", "POST, Get, OPTIONS, DELETE");
Res.setheader ("Access-control-max-age", "0");
Res.setheader ("Access-control-allow-headers", "Origin, No-cache, X-requested-with, If-modified-since, Pragma, Last-modified, Cache-control, Expires, Content-type, X-e4m-with,userid,token ");
Res.setheader ("Access-control-allow-credentials", "true");
Res.setheader ("xdomainrequestallowed", "1");
return true;
}


}

Front End section:

(function () {
$.ajax ({
Add these lines of code
Xhrfields: {
Withcredentials:true
},
Crossdomain:true,

});

This solves the Cross-domain problem