解决axios跨域问题，解决跨域请求sessionId不一致问题

axios.post跨域请求出错

①axios设置标题和转换请求数据 

var HTTP = axios.create({
      baseURL:'http://localhost:8080/',
      headers: {'Content-Type': 'application/x-www-form-urlencoded'},
      transformRequest: [function (data) {
        // Do whatever you want to transform the data
        let ret = ''
        for (let it in data) {
          ret += encodeURIComponent(it) + '=' + encodeURIComponent(data[it]) + '&'
        }
        return ret
      }]
    })

调用：

HTTP.post('admin/user/login.action',{
    name:'test',password:111
})
.then(function(response){
    console.log(response.data);
});

②后台写一个过滤器重写请求报头

public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletResponse res = (HttpServletResponse) servletResponse;
        HttpServletRequest request=(HttpServletRequest)servletRequest;
        res.setContentType("textml;charset=UTF-8");
        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");
        filterChain.doFilter(servletRequest,servletResponse);
    }

跨域请求时的sessionId不一致 

axios设置：

import axios from 'axios'
axios.defaults.withCredentials = true

$.ajax设置：

$.ajax({
url:url,
//加上这句话
xhrFields: {
   withCredentials: true
},
crossDomain: true,
success:function(result){
alert("test");
},
error:function(){
}
});