避免在Javascript前端和Java后端重复验证代码？

We are having a standard web application, and front-end is using Angular, back-end is written in Java 7. What I noticed, is that we get a lot of duplicating code. That is, validation is performed client-side by angular, but I cannot trust him completely, since the user can disable client-side validation and simply submit a post query to server.We are having a standard web application, and f