如何在java.net.URLConnection上指定本地地址？

Question

我的Tomcat實例正在偵聽多個IP地址，但我想控制打開URLConnection時使用的是哪個源IP地址。

我該如何指定？

Answer 1

這應該做的伎倆：

URL url = new URL(yourUrlHere); 
Proxy proxy = new Proxy(Proxy.Type.DIRECT, 
    new InetSocketAddress( 
     InetAddress.getByAddress(
      new byte[]{your, ip, interface, here}), yourTcpPortHere)); 
URLConnection conn = url.openConnection(proxy); 

和你做。 不要忘記處理例外很好，當然，改變價值觀，以適應你的情況。

啊，我省略了import語句

Answer 2

顯而易見的便攜方式是在URL.openConnection中設置代理。代理可以在本地主機中，然後您可以編寫一個非常簡單的代理來綁定客戶端套接字的本地地址。

如果無法修改URL所連接的源，則可以在調用URL構造函數或全局URL.setURLStreamHandlerFactory時替換URLStreamHandler。然後，URLStreamHandler可以委託給默認的http/https處理程序，修改openConnection調用。

更極端的方法是完全替換處理程序（可能會擴展JRE中的實現）。或者，可選擇（開源）http客戶端。

Answer 3

使用Apache Commons的HttpClient我還發現了以下工作（除去試/爲了清晰捕捉）：

HostConfiguration hostConfiguration = new HostConfiguration(); 
byte b[] = new byte[4]; 
b[0] = new Integer(192).byteValue(); 
b[1] = new Integer(168).byteValue(); 
b[2] = new Integer(1).byteValue(); 
b[3] = new Integer(11).byteValue(); 

hostConfiguration.setLocalAddress(InetAddress.getByAddress(b)); 

HttpClient client = new HttpClient(); 
client.setHostConfiguration(hostConfiguration); 
GetMethod method = new GetMethod("http://remoteserver/"); 
method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, 
    new DefaultHttpMethodRetryHandler(3, false)); 
int statusCode = client.executeMethod(method); 

if (statusCode != HttpStatus.SC_OK) { 
    System.err.println("Method failed: " + method.getStatusLine()); 
} 

byte[] responseBody = method.getResponseBody(); 
System.out.println(new String(responseBody));"); 

但是，我仍然不知道什麼如果IP的網關關閉（在這種情況下爲192.168.1.11），就會發生。下一個網關會被嘗試還是會失敗？

Answer 4

手動設定插座做工精細...

private HttpsURLConnection openConnection(URL src, URL dest, SSLContext sslContext) 
     throws IOException, ProtocolException { 
    HttpsURLConnection connection = (HttpsURLConnection) dest.openConnection(); 
    HttpsHostNameVerifier httpsHostNameVerifier = new HttpsHostNameVerifier(); 
    connection.setHostnameVerifier(httpsHostNameVerifier); 
    connection.setConnectTimeout(CONNECT_TIMEOUT); 
    connection.setReadTimeout(READ_TIMEOUT); 
    connection.setRequestMethod(POST_METHOD); 
    connection.setRequestProperty(CONTENT_TYPE, SoapConstants.CONTENT_TYPE_HEADER); 
    connection.setDoOutput(true); 
    connection.setDoInput(true); 
    connection.setSSLSocketFactory(sslContext.getSocketFactory()); 
    if (src!=null) { 
     InetAddress inetAddress = InetAddress.getByName(src.getHost()); 
     int destPort = dest.getPort(); 
     if (destPort <=0) 
      destPort=SERVER_HTTPS_PORT; 
     int srcPort = src.getPort(); 
     if (srcPort <=0) 
      srcPort=CLIENT_HTTPS_PORT; 
     connectionSocket = connection.getSSLSocketFactory().createSocket(dest.getHost(), destPort, inetAddress, srcPort); 
    } 
    connection.connect(); 
    return connection; 
}