1.用了fetch api，因为要做session验证，所以tomcat的Access-Control-Allow-Origin设置为了我的ip
2.登录是post请求，下单也是post请求，但是登录正常，下单却提示跨域
3.提示如下，这个提示大家应该都见过很多遍了

Response to preflight request doesn't pass access control check: 
No 'Access-Control-Allow-Origin' header is present on the requested resource.

4.两个post请求都是如下代码

const postWithCookie=({url,body})=>{
    const fetchUrl=HOME_URL+url;
    let headers =new Headers({
        'Accept': 'application/json',
        'Content-Type': 'application/json;charset=UTF-8',
        'Access-Control-Allow-Credentials':'true',
    })
    return fetch(fetchUrl,{
        credentials: "include",
        method: "POST",
        headers:headers,
        body:body
    }).then(response=>{
        if(window.DEBUG){console.info('url',response)}
        return response.json();
    })
}

5.后台两个接口也是一模一样的设置，但请求的结果完全不同

6.下面是tomcat过滤器的一些设置

    
    
        CrossOrigin
        com.util.CrossOriginFilter
        
            AccessControlAllowOrigin
            http://192.168.0.165
        
        
            AccessControlAllowMethods
            POST, GET, DELETE, PUT
        
        
            AccessControlMaxAge
            3628800
        
        
            AccessControlAllowHeaders
            x-requested-with,Content-Type,Access-Control-Allow-Credentials,Access-Control-Allow-Origin
        
        
            AccessControlAllowCredentials
            true
        
    
    
        CrossOrigin
        /*
    

请教一下大大们，谢谢了。
真的搞不懂这个fetch，实在不行只能用ajax了。