NullPointerException when trying to inject Controllers using map - servlets

Question

I'm building a webapp modelled on the MVC architecture. Form data from a JSP page gets forwarded to a Dispatcher Servlet which delegates to the Controller. I've managed to inject a single controller and it works just fine.
For multiple controllers I've created a Mapping Handler in the servlet which maps the request to the relevant Controller by reading in a properties file. I've injected the Mapping Handler but I'm still getting a NullPointerException.
An additional ControllerBundle just abstracts the Controller and method name into one object. I'm using tomee webprofile 1.7.4
DispatcherServlet.java:
package a1;
// imports
public class DispatcherServlet extends HttpServlet {
#Inject
#Named("MappingHandler")
private MappingHandler MAPPING_HANDLER;
// ** Single controller **
// #Inject
// #Named("customerController")
// private CustomerController controller;
#Override
public void init() throws ServletException {
MAPPING_HANDLER.generate();
}
#Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
try {
String pathInfo = req.getPathInfo();
Controller controller = MAPPING_HANDLER.getController(pathInfo);
String methodName = MAPPING_HANDLER.getMethod(pathInfo);
Method method = controller.getClass().getDeclaredMethod(methodName, HttpServletRequest.class);
method.setAccessible(true);
method.invoke(controller, req);
req.getRequestDispatcher("/results.jsp").forward(req, resp);
// ** Single controller **
// String methodName = "addCustomer";
// Method method = controller.getClass().getDeclaredMethod(methodName, HttpServletRequest.class);
//
// method.setAccessible(true);
// method.invoke(controller, req);
// req.getRequestDispatcher("/success.jsp").forward(req, resp);
} catch (SecurityException | IllegalArgumentException | NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
throw new RuntimeException(e);
}
}
}
MappingHandler.java:
package a1;
// imports
#Named("MappingHandler")
public class MappingHandler {
private static final Map<String, ControllerBundle> CONTROLLER_BUNDLE_MAP = new HashMap<>();
private static final String PACK = "a1.";
void generate() {
try {
Properties props = new Properties();
InputStream is1 = this.getClass().getClassLoader().getResourceAsStream("mappings_h6.properties");
props.load(is1);
Enumeration e = props.propertyNames();
while (e.hasMoreElements()) {
String left = (String) e.nextElement();
String right = props.getProperty(left);
// ControllerBundle: abstraction containing both the Controller and the name of the method
ControllerBundle controllerBundle = new ControllerBundle(right, PACK);
CONTROLLER_BUNDLE_MAP.put(left, controllerBundle);
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
Controller getController(String pathInfo) {
ControllerBundle controllerBundle = CONTROLLER_BUNDLE_MAP.get(pathInfo);
Controller controller = controllerBundle.getController();
return controller;
}
String getMethod(String pathInfo) {
ControllerBundle controllerEntity1 = CONTROLLER_BUNDLE_MAP.get(pathInfo);
String methodName = controllerEntity1.getMethodName();
return methodName;
}
}
ControllerBundle.java:
package a1;
// imports
public class ControllerBundle {
private Controller controller;
private String methodName;
private static final Map<String, Controller> CONTROLLER_MAP = new HashMap<>();
public ControllerBundle(String value, String pack) {
String[] valueSplit = value.split("#");
String controllerName = valueSplit[0];
Controller controller = findController(pack, controllerName);
String methodName = valueSplit[1];
this.controller = controller;
this.methodName = methodName;
}
// Keep only one copy of every controller
private static Controller findController(String pack, String controllerName) {
try {
Class currentControllerClass = Class.forName(pack + controllerName);
for (String s : CONTROLLER_MAP.keySet()) {
Class existingControllerClass = CONTROLLER_MAP.get(s).getClass();
if (currentControllerClass == existingControllerClass) {
return (Controller) existingControllerClass.newInstance();
}
}
Controller currentController = (Controller) currentControllerClass.newInstance();
CONTROLLER_MAP.put(controllerName, currentController);
return currentController;
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {
throw new RuntimeException(e);
}
}
Controller getController() {
return controller;
}
String getMethodName() {
return methodName;
}
}
mappings_h6.properties:
/customer/add=CustomerController#addCustomer
/customer/update=CustomerController#updateCustomer
/account/create=AccountController#createAccount
/account/freeze=AccountController#freezeAccount
beans.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
bean-discovery-mode="all">
</beans>

Answer 1

do you have a beans.xml in WEB-INF or WEB-INF/classes/META-INF? Otherwise on tomee 1.x CDI is not activated.