java - 用不同的代理连接到特定的地址

我正在开发Java Web服务应用程序(使用JAX-WS)，该应用程序必须使用两个不同的代理来建立与Internet和Intranet的单独连接。作为解决方案，我尝试编写自己的java.net.ProxySelector，以返回Internet或Intranet的java.net.Proxy实例(类型为HTTP)。

在一个小的测试应用程序中，我尝试通过URL.openConnection()下载网页，然后再用我自己的默认ProxySelector进行替换。但这会导致异常:

问题:“如果我的ProxySelector只返回一个HTTP代理，为什么要尝试通过SOCKS建立连接？”

2问题:“是否有替代方法，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");
}
}

最佳答案

好的，我发现了问题。
如果请求的URL不包含端口，则HttpURLConnection会对OwnProxySelector.select()进行两次。
首先，HttpURLConnection用URI调用select()，其方案为“http”，但没有端口。 select()检查主机地址和端口是否与intranetAddress或ExtranetAddress等效。这不匹配，因为未提供端口。因此，选择返回直接连接的代理。
在第二个HttpURLConnection上，使用URI以及方案“socket”和端口80调用带有URI的select()。因此，由于select()检查主机地址和端口，而不是方案，所以它返回了HTTP代理。
现在，这是我的OwnProxySelector的更正版本。如果该端口未由URI给出，它将检查该方案并为HTTP或HTTPS设置默认端口。如果没有给出HTTP或HTTPS方案，它还会询问Java标准的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);
}

}
但是令我感到奇怪的是，当它从第一次调用获得直接连接Proxy时，HttpURLConnection进行了select()的第二次调用。