Java java.net.ProxySelector用法及代碼示例

// Java Program to illustrate ProxySelector Class 
// of java.net package 
// only creating methods here 
  
// Importing standard input output classes 
import java.io.IOException; 
// Importing classes from java.net package 
import java.net.InetSocketAddress; 
import java.net.Proxy; 
import java.net.ProxySelector; 
import java.net.SocketAddress; 
import java.net.URI; 
// Importing List and ArrayList as utility classes from 
// java.util package 
import java.util.ArrayList; 
import java.util.List; 
  
// Class 1 
// Helper class extending ProxySelector class 
public class PrivateDataProxy extends ProxySelector { 
  
    // According to API we need to return List<Proxy> 
    // even if we return only one element, so 
  
    // Creating List class object of Proxy type 
    private final List<Proxy> noProxy = new ArrayList<>(); 
    private final List<Proxy> proxies = new ArrayList<>(); 
  
    // Constructor of this class 
    public PrivateDataProxy() 
    { 
  
        // If no proxy required to access resource 
        // use Proxy.NO_PROXY 
        noProxy.add(Proxy.NO_PROXY); 
  
        // Creating  InetSocketAddress, and 
        // secure.connection.com doesn't exist 443 is an 
        // https port 
        InetSocketAddress inetSocketAddress 
            = new InetSocketAddress("secure.connection.com", 
                                    443); 
  
        // Now creating http proxy 
        Proxy proxy 
            = new Proxy(Proxy.Type.HTTP, inetSocketAddress); 
  
        // Finally adding proxy into proxy list 
        proxies.add(proxy); 
    } 
  
    // Method 1 of this class 
    //@Override 
    public List<Proxy> select(URI uri) 
    { 
        if (uri.getPath().startsWith("/confidential")) { 
            // If URI path starts with '/confidential' then 
            // use proxy server 
            return proxies; 
        } 
  
        // If url don't start with '/confidential' then 
        //  no need in proxy 
        return noProxy; 
    } 
  
    // Method 2 of this class 
    // @Override 
    public void connectFailed(URI arg0, SocketAddress arg1, 
                              IOException arg2) 
    { 
        // Properly handle connection failing 
    } 
}

// Java Program to illustrate ProxySelector Class 
// of java.net package 
// Using custom ProxySelector 
  
// Importing required classes from respective packages 
import java.io.IOException; 
import java.net.Proxy; 
import java.net.ProxySelector; 
import java.net.URISyntaxException; 
import java.net.URL; 
import java.util.List; 
  
// Main class 
public class ProxySelectorDemo { 
  
    // Main driver method 
    public static void main(String[] args) 
        throws URISyntaxException, IOException 
    { 
  
        // Passing the string uri 
        PrivateDataProxy privateDataProxy 
            = new PrivateDataProxy(); 
  
        // The setting the system-wide proxy selector 
        ProxySelector.setDefault(privateDataProxy); 
  
        // Print the default value 
        // using getDefault() method 
        System.out.println("Default value: "
                           + ProxySelector.getDefault()); 
  
        // Display message only 
        System.out.println( 
            "Getting proxy for /confidential"); 
  
        // Passing the string URL 
        String confidentialUrl 
            = "https://www.download.com/confidential"; 
  
        // Now, calling the constructor of the URL class 
        URL confidential = new URL(confidentialUrl); 
  
        // Requiring an proxy for url 
        List<Proxy> confidentialProxies 
            = privateDataProxy.select(confidential.toURI()); 
  
        // Show the proxy that was selected 
        System.out.println("Proxy to use : "
                           + confidentialProxies.get(0)); 
  
        // Display message only 
        System.out.println( 
            "Getting proxy for /non-confidential"); 
  
        // passing the string URL 
        // Custom URL as input 
        String nonConfidentialURL 
            = "https://www.download.com/non-confidential"; 
  
        // Now, calling the constructor of the URL class 
        URL nonConfidential = new URL(nonConfidentialURL); 
  
        // Requiring an proxy for URL 
        List<Proxy> nonConfidentialProxies 
            = privateDataProxy.select( 
                nonConfidential.toURI()); 
  
        // Display the proxy that was selected 
        System.out.println("Proxy to use : "
                           + nonConfidentialProxies.get(0)); 
    } 
}