如何在angularjs应用程序中防止页面刷新时jwt令牌丢失？

I am trying to authorize a user using jwt token. But if i refresh the page, the jwt gets lost and the token is not sent on subsequent requests to the server. I am using localstorage for storing the token and spring-mvc for backend. This is the service i have created:I am trying to authorize a user using jwt token