问题：
在前端、后端都正常启动且代码看上去正常的情况下，
页面报：Request failed with status code 500 AxiosError: Request failed with status code 500
控制台报：Proxy error: Could not proxy request /save from localhost:10000 to http://localhost:8080/ssm. See nodejs.org/api/errors.… for more information (ECONNREFUSED).
解决方法：
将代理的目标地址target代码中的localhost替换为127.0.0.1
