ProxySelector determines which resource has to be requested via proxy as a result return List<Proxy>
Methods of ProxySelector class :
| Method | Description |
|---|---|
| connectFailed() | This method is invoked when failed to establish a connection |
| getDefault() | This method is used for retrieving the system-wide ProxySelector |
| select() | This method returns Proxy to access resource |
| setDefault() | This method is used to set or unset the system-wide ProxySelector |
Illustration: Sample Code for logic
Java
// Java Program to illustrate ProxySelector Class// of java.net package// only creating methods here // Importing standard input output classesimport java.io.IOException;// Importing classes from java.net packageimport 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 packageimport java.util.ArrayList;import java.util.List; // Class 1// Helper class extending ProxySelector classpublic 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 }} |
Implementation: Using custom ProxySelector
Java
// Java Program to illustrate ProxySelector Class// of java.net package// Using custom ProxySelector // Importing required classes from respective packagesimport java.io.IOException;import java.net.Proxy;import java.net.ProxySelector;import java.net.URISyntaxException;import java.net.URL;import java.util.List; // Main classpublic 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 // 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 // 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)); }} |
Output:
Default value: entity.PrivateDataProxy@5cad8086 Getting proxy for /confidential Proxy to use : HTTP @ secure.connection.com:443 Getting proxy for /non-confidential Proxy to use : DIRECT
