This project is a simple HTTP server built using Java NIO (Non-blocking I/O) and the FreeMarker templating engine. The server handles basic GET and POST requests using a custom MVC-style framework.
- Non-blocking I/O using Java NIO (
SocketChannel,Selector) to handle multiple connections simultaneously. - Custom MVC Framework with annotations like
@GETContentand@PostContentto map HTTP routes to controller methods. - Dynamic HTML rendering with FreeMarker templating engine.
- Custom routing: Routes are dynamically extracted based on annotations.
- Request parsing: HTTP requests are parsed to extract method, headers, and query parameters.
src
└── org
└── Server
├── Main.java # The main server class with NIO event loop
├── MvcExample.java # Example MVC controller with routes
├── configs # Configuration-related classes
├── markerEngine # FreeMarker template integration
└── Utils # Utility classes (Response, Modle, etc.)
@MvcController: Defines a controller class and specifies the port.@MvcMapping: Maps a base URL to a controller class.@GETContent: Maps a method to a specific GET route.@PostContent: Maps a method to a specific POST route.@ParseHtmlFille: Marks methods that return HTML files using FreeMarker templates.
- Java 11 or higher
- Maven (or another build tool if you prefer)
-
Clone the Repository
git clone https://github.com/your-username/custom-nio-server.git cd custom-nio-server -
Build the Project You can use Maven to build the project (or any IDE like IntelliJ IDEA).
mvn clean install
-
Run the Server Run the
Main.javaclass which is the entry point of the server:java -cp target/custom-nio-server.jar org.Server.Main
-
Server Output You should see:
Server Started At port 8081
Once the server is running, you can test the endpoints with tools like curl, Postman, or simply by using a browser.
-
GET /mvc/hello
curl http://localhost:8081/mvc/hello?name=Ayan- This route invokes the
getContent2method inMvcExample.java. - It fetches a response from an external API (
https://jsonplaceholder.typicode.com/posts/1), then returns a FreeMarker-generated HTML page using theTest.ftltemplate.
- This route invokes the
-
POST /mvc/post
curl -X POST -d "name=example" http://localhost:8081/mvc/post- This route invokes the
getContentmethod inMvcExample.java, returning a simple string response based on the request.
- This route invokes the
-
GET /mvc/h
curl http://localhost:8081/mvc/h
- This route returns a simple HTML string.
-
Main Class (
Main.java)- Sets up a non-blocking server using
ServerSocketChannelandSelector. - Handles
OP_ACCEPTandOP_READevents, accepting connections and reading HTTP requests. - Based on the HTTP method (
GETorPOST), it routes requests to methods defined inMvcExampleusing reflection.
- Sets up a non-blocking server using
-
Routing
- Routes are mapped to methods using annotations like
@GETContentand@PostContent. - Methods in
MvcExample.javahandle different routes, and based on the annotation, the framework dynamically invokes the appropriate method.
- Routes are mapped to methods using annotations like
-
Request Parsing
- The
parseResponsemethod inMain.javaparses incoming HTTP requests, extracting headers, query parameters, and the request method (GET or POST).
- The
-
Dynamic HTML Rendering
- When methods annotated with
@ParseHtmlFilleare invoked, FreeMarker templates are used to render HTML pages with dynamic content.
- When methods annotated with
FreeMarker is used to render HTML pages dynamically. To add new templates, create .ftl files in your resources folder.
Example FreeMarker file: Test.ftl
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Hello Page</title>
</head>
<body>
<h1>Hello, ${name}!</h1>
<p>Here is the external API response: ${response}</p>
</body>
</html>Feel free to contribute to this project by creating pull requests, opening issues, or suggesting improvements.