Java Web Scraper Project

Overview

This is a robust and flexible web scraping application designed to extract data from websites efficiently and reliably. The project provides a comprehensive set of tools for web scraping, including concurrent processing, rate limiting, error handling, and detailed statistics tracking.

Features

1. Concurrent Web Scraping

• Multi-threaded scraping with configurable thread count
• Efficient task management using ExecutorService
• Supports processing multiple URLs simultaneously

2. Advanced Data Processing

• Flexible DataProcessor for transforming and sanitizing scraped content
• Metadata extraction and storage
• Content filtering and sanitization options

3. Robust Error Handling

• Retry mechanism for failed scrapes
• Detailed error tracking and categorization
• Exponential backoff for retry attempts

4. Rate Limiting

• Prevents overwhelming target websites
• Configurable delay between requests
• Domain-based access tracking

5. Comprehensive Statistics

• Track successful and failed scrapes
• Monitor processing times
• Collect domain-specific statistics
• Generate detailed scraping reports

Key Components

WebScraper

• Main scraping engine
• Manages URL queue and concurrent processing
• Supports custom configuration via builder pattern

ScraperWorker

• Individual worker for scraping a single URL
• Handles retry logic
• Extracts metadata and content

DataProcessor

• Processes and transforms scraped data
• Applies content filters
• Supports listener pattern for custom processing

ScraperStats

• Tracks and analyzes scraping performance
• Generates detailed statistical reports
• Monitors error types, content types, and domain performance

ScrapeData

• Represents scraped data from a single URL
• Stores content, metadata, and processing information
• Supports builder pattern for flexible object creation

Example Usage

// Create a WebScraper with custom configuration
WebScraper scraper = WebScraper.builder()
    .threadCount(4)
    .timeout(15000)
    .delayBetweenRequests(1000)
    .build();

// Add URLs to scrape
scraper.addUrl("http://books.toscrape.com/");
scraper.start();

// Get scraping results
List<ScrapeData> results = scraper.getResults();

Installation Requirements

• Java 17+
• Maven or Gradle
• Dependencies:
  • Jsoup (HTML parsing)
  • SLF4J (Logging)
  • Lombok (Optional, for reducing boilerplate code)

Configuration Options

• Thread count
• Request timeout
• Delay between requests
• Content filtering
• Metadata extraction

Logging

The project uses SLF4J for logging, providing detailed insights into the scraping process.

Error Handling

• Automatic retry mechanism
• Detailed error categorization
• Configurable retry count and backoff strategy

Performance Considerations

• Concurrent processing
• Rate limiting to prevent IP blocking
• Efficient memory management
• Configurable thread pool

Security and Ethics

• Respect robots.txt
• Implement reasonable request delays
• Use appropriate user agents
• Obtain necessary permissions before scraping

Potential Improvements

• Add support for proxy rotation
• Implement more advanced content extraction
• Create more sophisticated rate limiting
• Add support for authentication
• Enhance error recovery mechanisms

Disclaimer

Web scraping may be subject to legal and ethical constraints. Always ensure you have the right to scrape a website and comply with the site's terms of service.