将Java应用程序绑定到接口

Question

我通过两个接口拥有对GNU/Linux服务器的root访问权限。我正在使用Jericho和HtmlUnit来抓取一些网页。我想指定哪个接口应该用于HTTP连接。有没有办法在命令行或Java中做到这一点？

Answer 1

HTTP我想指定哪个接口应该用于

连接。

每个网络接口都有自己的唯一IP地址。您可以通过连接到接口的IP地址上的端口来绑定到接口。

我不能访问套接字。我给了HtmlUnit一个网址。

无论您是使用套接字(通过Socket / InetAddress)还是HTTP连接(通过URL)，都使用相同的方法-绑定到IP地址+端口。

确定哪个接口具有哪个地址的

• 使用Linux命令：

ip a ip link show /sbin/ifconfig -a lshw -class network

• Use Java (java.net.NetworkInterface类)：

导入java.io.*；导入java.net.*；导入java.util.*；导入静态java.lang.System.out；公共类ListNIFs { public static void main(String args[])抛出SocketException {枚举网络= NetworkInterface.getNetworkInterfaces()；for (NetworkInterface netIf : Collections.list( nets )) {out.printf(“显示名称：%s\n"，netIf.getDisplayName())；Out.printf(“名称：%s\n"，netIf.getName())；枚举inetAddresses = netIf.getInetAddresses()；for (InetAddress add : Collections.list(inetAddresses)) { out.printf("Address：%s\n"，add.getName().getAddress().getHostAddress())；} displaySubInterfaces(netIf)；out.printf("\n")；}}静态无效displaySubInterfaces(NetworkInterface netIf)抛出SocketException {枚举subIfs = netIf.getSubInterfaces()；for (NetworkInterface subIf : Collections.list(subIfs)) { out.printf("\tSub接口显示名称：%s\n"，subIf.getDisplayName())；out.printf("\tSub接口名称：%s\n"，subIf.getName())；枚举inetAddresses = subIf.getInetAddresses()；for (InetAddress add : Collections.list(inetAddresses)) {out.printf(“\t子接口地址：%s\n"，add.getName().getAddress().getHostAddress())；}

HTML单元:指定IP地址和端口

如果您正在调用HTMLUnit的WebClient，例如：

com.gargoylesoftware.htmlunit.WebClient webClient = new WebClient();
com.gargoylesoftware.htmlunit.html.HtmlPage page = 
    webClient.getPage("http://mycompany.org/mypage");

然后，您可以执行以下任一操作：

com.gargoylesoftware.htmlunit.html.HtmlPage page = 
    webClient.getPage("http://255.255.255.0:80/mypage");

java.net.URL url = new java.net.URL("http://255.255.255.0:80/mypage");
page = webClient.getPage(url);

com.gargoylesoftware.htmlunit.WebRequest req = 
    new com.gargoylesoftware.htmlunit.WebRequest(url, com.gargoylesoftware.htmlunit.HttpMethod.GET);
page = webClient.getPage(req);

您还可以使用HTMLUnit HttpWebConnection

com.gargoylesoftware.htmlunit.HttpWebConnection conn = 
    new com.gargoylesoftware.htmlunit.HttpWebConnection(webClient);
java.net.URL url = new java.net.URL("http://255.255.255.0/mypage");
com.gargoylesoftware.htmlunit.WebRequest req = 
    new com.gargoylesoftware.htmlunit.WebRequest(url, com.gargoylesoftware.htmlunit.HttpMethod.POST);
com.gargoylesoftware.htmlunit.WebRequest resp = conn.getResponse(req);

HTTP :为连接指定URL的选项

创建URL以连接到资源(文件、网页等)。您可以使用主机字符串(自动DNS查找)或IP地址指定URL。您可以选择添加端口：

    // does not encode URL for you (manually include %20, etc)
    java.net.URL url = 
        new URL("http://255.255.255.20:80/docs/books/tutorial/index.html?name=networking#DOWNLOADING");
    java.net.URL url2 = new URL("http", "255.255.255.20", 80, 
                                "/docs/books/tutorial/index.html?name=networking#DOWNLOADING");
    java.net.URL url3 = new java.net.URL("https://maps.google.com/maps?q=sydney");
    java.net.URL url4 = new java.net.URL("https", "maps.google.com", 80, "/maps?q=sydney");

    // does encoding of URL string for you 
    java.net.URI uri5 = new URI("http", "example.com", "/hello world/", "");
    java.net.URL url5 = uri2.toURL();

    // Can then pass URL to HTMLUnit, or invoke yourself 
    // (see Java Network Tutorial for details):

    java.net.URLConnection conn = url.openConnection();
    java.net.HttpConnection httpConn = (HttpConnection)conn;
    // preconnection: call setAllowUserInteraction/setDoInput/setDoOutput/    
    //                     setIfModifiedSince/setUseCaches/setRequestProperty
    httpConn.connect();  // or getInputStream/getOutputStream/getContent/getHeaderField
    // postconnection: call getContentEncoding/getContentLength/getContentType
    //                      getDate/getExpiration/getLastModifed

核心Java:指定InetAddress (用于套接字连接)的选项

使用IP地址

    // 4 bytes:
    byte[] ip4Address = {101,119,11,106};  
    java.net.InetAddress addressObj = java.net.InetAddress.getByAddress(ip4Address); 

    // or use ip6Address, 16 bytes (2001:0db8:85a3:0000:0000:8a2e:0370:7334):
    // Any hex value above 0x7f must be cast to byte, because byte is signed (-128 to 127)
    byte[] ip6Address = {0x20,0x01,0x0d,(byte)0xb8,(byte)0x85,(byte)0xa3,0x00,0x00,0x00,0x00,(byte)0x8a,0x2e,0x03,0x70,0x73,0x34}; 

使用URL字符串(DNS查找)

    java.net.InetAddress addressObj = java.net.InetAddress.getByName("www.google.com");

Answer 2

在Java中，您必须将套接字绑定到要使用的NIC的本地IP地址。如果您使用的是0.0.0.0，它将绑定到所有。指定它只使用你想要的那一个。

Answer 3

有两种方法可以做到这一点。

1. 在Java中，关键点是在调用HTTPConnection#open()方法之前指定要使用的源地址：

InetAddress favourateAddr = InetAddress(byte[] {1,2,3,4})；// 1.2.3.4是您要使用的网卡的ip地址

yourHTTPConnObj.setLocalAddress(favourateAddr)；

//然后打开http connection yourHTTPConnObj.open();

• In Linux，选择网卡的路由由三层utils决定。因此，您需要使用目标地址自定义路由表，强制您的连接从哪个网卡开始。它非常简单，只有一个路由命令。请参阅this link.