无法在 WebFilter 中将 Principal 强制转换为 KeycloakPrincipal 但 servlet 没有问题

Question

环境：

• Jboss7.2
• 钥匙斗篷 6.0.1
• Java 11

我正在尝试强制转换 Principal 以获取 Keycloak 用户信息，但我收到了 ClassCastException。 WebFilter 和 WebServlet 位于不同的 maven 模块中。

org.keycloak.KeycloakPrincipal 位于加载程序 'org.keycloak.keycloak-core@11.0.2' @4d7642f0 的未命名模块中； org.keycloak.KeycloakPrincipal 位于加载程序“deployment.app.ear”@4d7682a1 的未命名模块中

错误日志

cast: java.lang.ClassCastException: 
    class org.keycloak.KeycloakPrincipal cannot be cast to class org.keycloak.KeycloakPrincipal       
    (org.keycloak.KeycloakPrincipal is in unnamed module of loader 'org.keycloak.keycloak-core@11.0.2' @4d7642f0; org.keycloak.KeycloakPrincipal is in unnamed module of loader 'deployment.app.ear' @4d7682a1
...

pom.xml（根）

...
<modules>
   <module>app-back</module> <!--where webservlet is-->
   <module>app-ejb</module> <!--where webfilter is-->
   <module>app-ear</module>
</modules>
...

WebFilter CAST KO

@WebFilter(filterName = "Filter", urlPatterns = "/*")
public class FilterPrincipal implements Filter {
    ...

    @Override
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws java.io.IOException, ServletException {
        ...
        HttpServletRequest sReq = ((HttpServletRequest) req);
        
        KeycloakPrincipal<KeycloakSecurityContext> kp = (KeycloakPrincipal<KeycloakSecurityContext>) principal;//error
        
        KeycloakSecurityContext keycloakSecurityContext = kp.getKeycloakSecurityContext();

        AccessToken token = keycloakSecurityContext.getToken();
        writer.println("username = " + token.getPreferredUsername());
        
        ...
        chain.doFilter(req, resp);
    }
    ...
    
**WebServlet CAST OK**

@WebServlet(urlPatterns = "/principal")
public class PrincipalInfoServlet extends HttpServlet {

    ...

    @SuppressWarnings("unchecked")
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {

        ...
        Principal principal = request.getUserPrincipal();
        if (principal != null) {
            ...

            // API keycloak
            if (principal instanceof KeycloakPrincipal<?>) {
                writer.println("--------------------------------");
                writer.println("Informació del token de keycloak:");

                KeycloakPrincipal<KeycloakSecurityContext> kp = (KeycloakPrincipal<KeycloakSecurityContext>) principal;//OK
                KeycloakSecurityContext keycloakSecurityContext = kp.getKeycloakSecurityContext();
    ...

Answer 1

我通过将 webservlet 移动到 maven modul app-back 找到了一种解决方法，因此 KeycloakPrincipals 在同一个模块中。