Framework

A lightweight Java MVC framework built from scratch, inspired by Spring MVC. Handles HTTP routing, annotation scanning, view rendering, and optional Spring container integration — without depending on Spring MVC itself.

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How it works

HTTP Request
    └── FrontControllerServlet
            └── looks up UrlKey(path, httpMethod) in urlList
            └── finds Mapping(className, methodName)
            └── instantiates the controller via reflection
            └── invokes the method (with or without ApplicationContext)
            └── renders the result (ModelAndView, String, or void)

The URL map is built once at startup by InitListener, which scans the classpath for @Controller classes and collects every @UrlMapping method into a Map<UrlKey, Mapping> stored in the ServletContext.

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Project structure

src/main/java/randy/framework/
├── annotation/
│   ├── Controller.java       — marks a class as a controller
│   └── UrlMapping.java       — maps a method to a URL + HTTP method(s)
├── listener/
│   └── InitListener.java     — scans packages at startup, builds urlList
├── model/
│   ├── Mapping.java          — holds className + methodName for a route
│   ├── ModelAndView.java     — holds view name + data model (Map<String, Object[]>)
│   └── UrlKey.java           — composite key (url + httpMethod) for the route map
├── servlet/
│   └── FrontControllerServlet.java  — single entry point for all requests
├── helper/
│   └── ViewRenderer.java     — interface for view rendering strategies
└── util/
    ├── HtmlViewRenderer.java — replaces {placeholder} tokens in .html files
    ├── JspViewRenderer.java  — forwards to .jsp files via RequestDispatcher
    └── Utilitaire.java       — classpath scanner using ClassGraph

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Annotations

@Controller

Marks a class as a controller. The scanner picks it up during startup.

@Controller
public class BookController { }

@UrlMapping

Maps a method to a URL path and one or more HTTP methods. Defaults to both GET and POST if method is omitted.

@UrlMapping(value = "/books", method = "GET")
public ModelAndView list(ApplicationContext ctx) { ... }

@UrlMapping(value = "/books", method = "POST")
public String save() { ... }

@UrlMapping("/")   // default → GET + POST
public void home() { ... }

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Controller method return types

Return type	What happens
ModelAndView	Sets model attributes on the request, renders the named view
String	Treated as the view name, rendered with no model data
void	Method executes, framework shows a debug confirmation page

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Spring container integration

If a controller method declares ApplicationContext as its only parameter, the framework fetches the Spring container from the ServletContext and passes it automatically:

@UrlMapping(value = "/books", method = "GET")
public ModelAndView list(ApplicationContext ctx) {
    BookService service = ctx.getBean(BookService.class);
    // ...
}

The framework instantiates controllers itself. Spring manages services and repositories only.

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View rendering

Views are resolved as prefix + viewName + suffix, configured in web.xml.

JSP — forwards via RequestDispatcher. Use JSTL EL expressions:

<c:forEach var="item" items="${myList}">
    <li>${item.title}</li>
</c:forEach>

HTML — replaces {placeholder} tokens with values from the model:

<p>{message}</p>

The renderer is selected automatically based on the configured suffix (.jsp, .html, .htm).

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web.xml configuration

<!-- package your @Controller classes live in -->
<init-param>
    <param-name>packageToScan</param-name>
    <param-value>com.example.controller</param-value>
</init-param>

<!-- view resolver -->
<context-param>
    <param-name>prefix</param-name>
    <param-value>/WEB-INF/views/</param-value>
</context-param>
<context-param>
    <param-name>suffix</param-name>
    <param-value>.jsp</param-value>
</context-param>

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Build and install

# From the Framework directory
mvn clean install
# Publishes randy.framework:framework:1.0 to your local ~/.m2 repository
# Run this every time you change the framework before rebuilding Code-Test