[java] How to check "hasRole" in Java Code with Spring Security?

The @gouki answer is best!

Just a tip of how spring really do this.

There is a class named SecurityContextHolderAwareRequestWrapper which implements the ServletRequestWrapper class.

The SecurityContextHolderAwareRequestWrapper overrides the isUserInRole and search user Authentication (which is managed by Spring) to find if user has a role or not.

SecurityContextHolderAwareRequestWrapper the code is as:

    @Override
    public boolean isUserInRole(String role) {
        return isGranted(role);
    }

 private boolean isGranted(String role) {
        Authentication auth = getAuthentication();

        if( rolePrefix != null ) {
            role = rolePrefix + role;
        }

        if ((auth == null) || (auth.getPrincipal() == null)) {
            return false;
        }

        Collection<? extends GrantedAuthority> authorities = auth.getAuthorities();

        if (authorities == null) {
            return false;
        }

        //This is the loop which do actual search
        for (GrantedAuthority grantedAuthority : authorities) {
            if (role.equals(grantedAuthority.getAuthority())) {
                return true;
            }
        }

        return false;
    }