使用不同的代理连接到特定地址

Question

我正在开发一个 Java Web 服务应用程序（使用 JAX-WS），它必须使用两个不同的代理来建立与互联网和 Intranet 的独立连接。作为解决方案，我尝试编写自己的 java.net.ProxySelector ，它为互联网或 Intranet 返回一个 java.net.Proxy 实例（HTTP 类型）。

在一个小测试应用程序中，我尝试通过 URL.openConnection() 下载网页，然后用我自己的代理选择器替换默认的代理选择器。但这会导致异常：

java.net.SocketException：未知的代理类型：HTTP 在 java.net.SocksSocketImpl.connect(SocksSocketImpl.java:370) 在 java.net.Socket.connect(Socket.java:519) 在 java.net.Socket.connect(Socket.java:469) 在 sun.net.NetworkClient.doConnect(NetworkClient.java:163) 在 sun.net.www.http.HttpClient.openServer(HttpClient.java:394) 在 sun.net.www.http.HttpClient.openServer(HttpClient.java:529) 在 sun.net.www.http.HttpClient.(HttpClient.java:233) 在 sun.net.www.http.HttpClient.New(HttpClient.java:306) 在 sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:844) 在 sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:792) 在 sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:703) 在 sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1026) 在 java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:373) 在norman.test.ProxyTest.conntectToRmViaProxy（ProxyTest.java：42） 在norman.test.ProxyTest.main(ProxyTest.java:65)

1. 问题：“如果我的 ProxySelector 仅返回 HTTP 代理，为什么尝试应用程序通过 SOCKS 建立连接？”

2 问题：“是否有其他选择，为每个连接定义不同的代理？”

这是我的 ProxySelector：

public class OwnProxySelector extends ProxySelector {
private Proxy intranetProxy;
private Proxy extranetProxy;
private Proxy directConnection = Proxy.NO_PROXY;
private URI intranetAddress;
private URI extranetAddress;

/* (non-Javadoc)
 * @see java.net.ProxySelector#connectFailed(java.net.URI, java.net.SocketAddress, java.io.IOException)
 */
public void connectFailed(URI uri, SocketAddress sa, IOException ioe) {
    // Nothing to do
}

/* (non-Javadoc)
 * @see java.net.ProxySelector#select(java.net.URI)
 */
public List select(URI uri) {
    ArrayList<Proxy> result = new ArrayList<Proxy>();

    if(intranetAddress.getHost().equals(uri.getHost()) && intranetAddress.getPort()==uri.getPort()){
        result.add(intranetProxy);
        System.out.println("Adding intranet Proxy!");
    }
    else if(extranetAddress.getHost().equals(uri.getHost()) && extranetAddress.getPort()==uri.getPort()){
        result.add(extranetProxy);
        System.out.println("Adding extranet Proxy!");
    }
    else{
        result.add(directConnection);
        System.out.println("Adding direct connection!");
    }

    return result;
}

public void setIntranetProxy(String proxyAddress, int proxyPort){
    if(proxyAddress==null || proxyAddress.isEmpty()){
        intranetProxy = Proxy.NO_PROXY;
    }
    else{
        SocketAddress address = new InetSocketAddress(proxyAddress, proxyPort);
        intranetProxy = new Proxy(Proxy.Type.HTTP, address);
    }
}

public void setExtranetProxy(String proxyAddress, int proxyPort){
    if(proxyAddress==null || proxyAddress.isEmpty()){
        extranetProxy = Proxy.NO_PROXY;
    }
    else{
        SocketAddress address = new InetSocketAddress(proxyAddress, proxyPort);
        extranetProxy = new Proxy(Proxy.Type.HTTP, address);
    }
}

public void clearIntranetProxy(){
    intranetProxy = Proxy.NO_PROXY;
}

public void clearExtranetProxy(){
    extranetProxy = Proxy.NO_PROXY;
}

public void setIntranetAddress(String address) throws URISyntaxException{
    intranetAddress = new URI(address);
}

public void setExtranetAddress(String address) throws URISyntaxException{
    extranetAddress = new URI(address);
}
}

这是测试类：

public class ProxyTest {
OwnProxySelector ownSelector = new OwnProxySelector();

public ProxyTest(){
    ownSelector.setIntranetProxy("intranet.proxy", 8123);
    try {
        ownSelector.setIntranetAddress("http://intranet:80");
    } catch (URISyntaxException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    ownSelector.setExtranetProxy("", 0);
    try {
        ownSelector.setExtranetAddress("http://www.example.com:80");
    } catch (URISyntaxException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }


    ProxySelector.setDefault(ownSelector);
}

public void conntectToRmViaProxy(boolean internal, String connectAddress){
    try {
        URL url = new URL(connectAddress);

        HttpURLConnection conn = (HttpURLConnection)url.openConnection();

        conn.setRequestMethod("GET");
          if (conn.getResponseCode() != HttpURLConnection.HTTP_OK) {
            System.out.println(conn.getResponseMessage());
          }
          else{
              BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
              int tmp = reader.read();
              while(tmp != -1){
                  System.out.print((char)tmp);
                  tmp = reader.read();
              }
          }

    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public static void main(String[] args){
    ProxyTest proxyText = new ProxyTest();
    proxyText.conntectToRmViaProxy(true, "http://intranet:80");
}
}

Answer 1

好的，我已经找到问题了。

如果请求的 URL 不包含端口，则 HttpURLConnection 会执行 OwnProxySelector.select() 两次。

首先，HttpURLConnection 使用 URI 调用 select()，Scheme 为“http”但没有端口。 select() 检查主机地址和端口是否与 IntranetAddress 或 ExtranetAddress 相同。这不匹配，因为未给出端口。因此选择返回一个用于直接连接的代理。

第二次 HttpURLConnection 使用 URI、“socket”方案和端口 80 调用 select()。因此，因为 select() 检查主机地址和端口，但不检查方案，所以它返回一个 HTTP 代理。

现在这是我修正后的 OwnProxySelector 版本。它检查方案并设置 HTTP 或 HTTPS 的默认端口（如果 URI 未给出端口）。如果没有给出 HTTP 或 HTTPS 方案，它还会询问 Java 标准 ProxySelector。

public class OwnProxySelector extends ProxySelector {
private ProxySelector defaultProxySelector;
private Proxy intranetProxy;
private Proxy extranetProxy;
private Proxy directConnection = Proxy.NO_PROXY;
private URI intranetAddress;
private URI extranetAddress;


public OwnProxySelector(ProxySelector defaultProxySelector){
    this.defaultProxySelector = defaultProxySelector;
}

/* (non-Javadoc)
 * @see java.net.ProxySelector#connectFailed(java.net.URI, java.net.SocketAddress, java.io.IOException)
 */
public void connectFailed(URI uri, SocketAddress sa, IOException ioe) {
    // Nothing to do
}

/* (non-Javadoc)
 * @see java.net.ProxySelector#select(java.net.URI)
 */
public List select(URI uri) {
    ArrayList<Proxy> result = new ArrayList<Proxy>();
    
    if(uri.getScheme().equalsIgnoreCase("http") || uri.getScheme().equalsIgnoreCase("https")){
        int uriPort = uri.getPort();
        
        // set default http and https ports if port is not given in URI
        if(uriPort<1){
            if(uri.getScheme().equalsIgnoreCase("http")){
                uriPort = 80;
            }
            else if(uri.getScheme().equalsIgnoreCase("https")){
                uriPort = 443;
            }
        }
        
        if(intranetAddress.getHost().equals(uri.getHost()) && intranetAddress.getPort()==uriPort){
            result.add(intranetProxy);
            System.out.println("Adding intranet Proxy!");
        }
        else if(extranetAddress.getHost().equals(uri.getHost()) && extranetAddress.getPort()==uriPort){
            result.add(extranetProxy);
            System.out.println("Adding extranet Proxy!");
        }
    }
    
    if(result.isEmpty()){
        List<Proxy> defaultResult = defaultProxySelector.select(uri);
        if(defaultResult!=null && !defaultResult.isEmpty()){
            result.addAll(defaultResult);
            System.out.println("Adding Proxis from default selector.");
        }
        else{
            result.add(directConnection);
            System.out.println("Adding direct connection, because requested URI does not match any Proxy");
        }
    }
    
    return result;
}

public void setIntranetProxy(String proxyAddress, int proxyPort){
    if(proxyAddress==null || proxyAddress.isEmpty()){
        intranetProxy = Proxy.NO_PROXY;
    }
    else{
        SocketAddress address = new InetSocketAddress(proxyAddress, proxyPort);
        intranetProxy = new Proxy(Proxy.Type.HTTP, address);
    }
}

public void setExtranetProxy(String proxyAddress, int proxyPort){
    if(proxyAddress==null || proxyAddress.isEmpty()){
        extranetProxy = Proxy.NO_PROXY;
    }
    else{
        SocketAddress address = new InetSocketAddress(proxyAddress, proxyPort);
        extranetProxy = new Proxy(Proxy.Type.HTTP, address);
    }
}

public void clearIntranetProxy(){
    intranetProxy = Proxy.NO_PROXY;
}

public void clearExtranetProxy(){
    extranetProxy = Proxy.NO_PROXY;
}

public void setIntranetAddress(String address) throws URISyntaxException{
    intranetAddress = new URI(address);
}

public void setExtranetAddress(String address) throws URISyntaxException{
    extranetAddress = new URI(address);
}

但

令我好奇的是，当 HttpURLConnection 从第一次调用获得直接连接代理时，它第二次调用了 select()。