🌤️ Java Weather Web Application

A full-stack Java web application built with Servlets, JSP, and the OpenWeatherMap API to deliver real-time weather forecasts.

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📖 Table of Contents

• Description
• Screenshots
• Features
• Architecture & Workflow
• Technologies Used
• Setup Instructions
• API Integration Details
• Author

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📝 Description

WeatherApp is a robust, dynamic Java-based web application that fetches and displays real-time weather data. It is developed using Java Servlets, JavaServer Pages (JSP), HTML, CSS, and JavaScript. By integrating seamlessly with the OpenWeatherMap API, the application dynamically updates based on the user's city input, returning essential meteorological data like temperature, humidity, wind speed, and visibility.

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📸 Screenshots

Home Page / Search	Weather Data Display	Detailed Metrics

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✨ Features

• Real-Time Data Fetching: Instantly retrieves live weather data based on the provided city name.
• Comprehensive Metrics: Displays detailed current weather conditions including:
  • 🌡️ Temperature
  • 💧 Humidity
  • 💨 Wind Speed
  • 👁️ Visibility
  • ☁️ Cloud Cover
• Dynamic UI: A clean, responsive front-end built with HTML, CSS, and JavaScript.
• MVC Pattern Structure: Separates business logic (Servlet) from the presentation layer (JSP).

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⚙️ Architecture & Workflow

1. Client Request: The user submits a city name via the HTML form on index.jsp.
2. Controller (Servlet): MyServlet.java handles the HTTP POST request.
3. API Integration: The Servlet constructs an API call to OpenWeatherMap using HttpURLConnection.
4. Data Parsing: The JSON response is parsed into Java objects using the Gson library.
5. Data Transfer: Weather attributes are mapped and set to HttpServletRequest attributes.
6. View (JSP): The request is forwarded to index.jsp, where Expression Language (EL) is used to render the data dynamically.

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💻 Technologies Used

Backend:

• Java Servlets (Controller & Business Logic)
• Gson Library (JSON Parsing)

Frontend:

• JavaServer Pages (JSP) (Dynamic Views & EL)
• HTML5 & CSS3 (Structure & Styling)
• JavaScript (Client-side interactivity)

Server & Tools:

• Apache Tomcat 10.x (Web Server / Servlet Container)
• Eclipse IDE / IntelliJ IDEA
• OpenWeatherMap REST API

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🛠️ Setup Instructions

Prerequisites

• Java Development Kit (JDK) 11 or higher
• Apache Tomcat 10.1.x
• Eclipse IDE for Enterprise Java (or IntelliJ IDEA Ultimate)
• OpenWeatherMap API Key

Installation Steps

1. Clone the Repository

   git clone https://github.com/naamsanamone/WeatherApp.git

2. Configure IDE & Server

   • Open Eclipse IDE.
   • Go to Window -> Preferences -> Server -> Runtime Environments.
   • Click Add, select Apache Tomcat v10.1.x, and point to your Tomcat installation directory.

3. Import Project

   • Go to File -> Import -> Existing Projects into Workspace.
   • Select the cloned WeatherApp directory.

4. Add Gson Dependency

   • Ensure gson-x.x.x.jar is present in src/main/webapp/WEB-INF/lib.
   • If missing, download it and manually add it to the project's Build Path.

5. Configure API Key

   • Sign up at OpenWeatherMap to get an API key.
   • Open src/main/java/MyPackage/MyServlet.java.
   • Replace the placeholder myApiKey with your actual API key:

     String apiKey = "YOUR_ACTUAL_API_KEY_HERE";

6. Run the Application

   • Right-click the project in Eclipse -> Run As -> Run on Server.
   • Select your configured Tomcat instance.
   • Access the app at: http://localhost:8080/WeatherApp

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🔌 API Integration Details

HTTP Request

• Utilizes java.net.HttpURLConnection to establish a GET request to the OpenWeatherMap API endpoint.
• Reads the response via InputStreamReader and Scanner.

JSON Processing

• The raw JSON string is parsed into a JsonObject using Google's Gson library.
• Extracts deeply nested fields (e.g., main.temp, wind.speed, weather[0].main).

Dispatching

• The parsed values are passed to the frontend using request.setAttribute().
• Uses RequestDispatcher.forward(request, response) to seamlessly render index.jsp without a redirect.

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👨‍💻 Author

Sai Venkat

• GitHub: @naamsanamone

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_{Developed with Java, Servlets, and the OpenWeather API.}