记一次ajax跨域

这两天做一个项目，本地测试的时候，发现前端ajax调接口跨域了，解决过程中又出现了每次请求sessionId都会变化，导致session失效的问题，记录一笔，以免以后遇到同样的问题又到处找解决方法。
1、后台springMvc，添加一个filter，设置头信息如下

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

public class CrossFilter implements Filter {

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub

    }


    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-Control-Allow-Origin", "https://st.gwold.com");
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        httpServletResponse.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");
        httpServletResponse.setHeader("Access-Control-Allow-Credentials", "true");

        filterChain.doFilter(request, httpServletResponse);
    }
}

web.xml中配置：

<filter>
  <filter-name>corsfilter-name>
  <filter-class>com.game.filter.cors.CrossFilterfilter-class>
filter>
<filter-mapping>
  <filter-name>corsfilter-name>
  /*
filter-mapping>

2、前端ajax中设置withCredentials为true
原生js写法：

var request = new XMLHttpRequest();
request.withCredentials = true;

jquery写法：

xhrFields: {
         withCredentials: true
      },