Tuesday, July 22, 2025

Java Download and Upload

# Java Network Speed Limiting and Unblocked Access

To control network speed (both download and upload) and ensure unblocked access in Java, you can use several approaches. Here are some methods:

## 1. Using Java's Network APIs with Rate Limiting

```java
import java.io.*;
import java.net.*;
import java.util.concurrent.*;

public class RateLimitedDownloader {
    private static final int DOWNLOAD_RATE_LIMIT = 1024 * 1024; // 1 MB/s
    private static final int UPLOAD_RATE_LIMIT = 512 * 1024;   // 512 KB/s
    
    public static void downloadWithLimit(String fileUrl, String localPath) throws IOException {
        URL url = new URL(fileUrl);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        
        try (InputStream in = new BufferedInputStream(connection.getInputStream());
             FileOutputStream out = new FileOutputStream(localPath)) {
            
            byte[] buffer = new byte[8192];
            long startTime = System.currentTimeMillis();
            int bytesRead;
            long totalBytesRead = 0;
            
            while ((bytesRead = in.read(buffer)) != -1) {
                out.write(buffer, 0, bytesRead);
                totalBytesRead += bytesRead;
                
                // Rate limiting
                long elapsedTime = System.currentTimeMillis() - startTime;
                long expectedTime = (totalBytesRead * 1000) / DOWNLOAD_RATE_LIMIT;
                
                if (elapsedTime < expectedTime) {
                    Thread.sleep(expectedTime - elapsedTime);
                }
            }
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }
}
```

## 2. Using Proxy Settings for Unblocked Access

```java
import java.net.*;

public class ProxyExample {
    public static void main(String[] args) {
        // Set proxy for unblocked access
        Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 8080));
        
        try {
            URL url = new URL("http://example.com");
            HttpURLConnection conn = (HttpURLConnection) url.openConnection(proxy);
            
            // Set authentication if needed
            // String auth = "username:password";
            // String encodedAuth = Base64.getEncoder().encodeToString(auth.getBytes());
            // conn.setRequestProperty("Proxy-Authorization", "Basic " + encodedAuth);
            
            // Read response
            BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                System.out.println(inputLine);
            }
            in.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
```

## 3. Using Java's Traffic Shaping (for advanced control)

For more precise network control, you can use libraries like Netty which provide traffic shaping:

```java
import io.netty.channel.*;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.traffic.*;

public class TrafficShapingInitializer extends ChannelInitializer<SocketChannel> {
    private static final long WRITE_LIMIT = 512 * 1024; // 512 KB/s upload
    private static final long READ_LIMIT = 1024 * 1024; // 1 MB/s download
    
    @Override
    protected void initChannel(SocketChannel ch) {
        ChannelPipeline pipeline = ch.pipeline();
        
        // Add traffic shaping handlers
        pipeline.addLast("trafficShapper", 
            new ChannelTrafficShapingHandler(WRITE_LIMIT, READ_LIMIT, 1000));
        
        // Add your other handlers...
    }
}
```

## 4. Using Java's NetworkInterface for Low-Level Control

```java
import java.net.*;
import java.util.Enumeration;

public class NetworkInterfaceExample {
    public static void main(String[] args) throws SocketException {
        Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
        
        while (interfaces.hasMoreElements()) {
            NetworkInterface ni = interfaces.nextElement();
            System.out.println("Interface: " + ni.getName());
            System.out.println("  Display name: " + ni.getDisplayName());
            System.out.println("  MTU: " + ni.getMTU());
            System.out.println("  Is up: " + ni.isUp());
            System.out.println("  Is loopback: " + ni.isLoopback());
        }
    }
}
```

## Important Notes:

1. **Rate Limiting**: The first approach shows a simple rate limiting technique, but for production use, consider more sophisticated algorithms like token bucket or leaky bucket.

2. **Proxy Settings**: For unblocked access, you might need to configure proxy settings properly, including authentication if required.

3. **Permissions**: On Android, you'll need appropriate permissions in your manifest:
```xml
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
```

4. **Advanced Control**: For more precise network control, consider using lower-level networking APIs or specialized libraries.

Would you like me to explain any of these approaches in more detail or focus on a specific aspect of network speed control in Java?

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