Java Socket-02 Java Socket地址

package com.iteye.xuj.socket;

import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.Enumeration;

public class InetAddressExample {
	public static void main(String[] args) {
		try {
			//静态方法getNetworkInterfaces()获取主机的网络接口列表
			Enumeration<NetworkInterface> interfaceList = NetworkInterface.getNetworkInterfaces();
			if (interfaceList == null) {
				System.out.println("--No interfaces found--");
			} else {
				//获取并打印出列表中每个接口的地址
				while (interfaceList.hasMoreElements()) {
					NetworkInterface iface = interfaceList.nextElement();
					//getName()方法为接口返回一个本地名称
					System.out.println("Interface " + iface.getName() + ":");
					//getInetAddresses()方法获取与接口相关联的地址
					Enumeration<InetAddress> addrList = iface.getInetAddresses();
					if (!addrList.hasMoreElements()) {
						System.out.println("\t(No addresses for this interface)");
					}
					while (addrList.hasMoreElements()) {
						InetAddress address = addrList.nextElement();
						System.out.print("\tAddress "
								+ ((address instanceof Inet4Address ? "(v4)" : (address instanceof Inet6Address ? "(v6)" : "(?)"))));
						//getHostAddress()方法返回一个字符串来代表主机的数字型地址
						System.out.println(": " + address.getHostAddress());
					}
				}
			}
		} catch (SocketException se) {
			System.out.println("Error getting network  interfaces:" + se.getMessage());
		}

		//获取从命令行输入的每个参数所对应的主机名和地址
		for (String host : args) {
			try {
				System.out.println(host + ":");
				InetAddress[] addressList = InetAddress.getAllByName(host);
				for (InetAddress address : addressList) {
					System.out.println("\t" + address.getHostName() + "/" + address.getHostAddress());
				}
			} catch (UnknownHostException e) {
				System.out.println("\tUnable to find address for " + host);
			}
		}
	}
}

运行时参数：127.0.0.1 localhost

输出结果：

Interface lo:
	Address (v6): 0:0:0:0:0:0:0:1
	Address (v4): 127.0.0.1
Interface net0:
	(No addresses for this interface)
Interface net1:
	(No addresses for this interface)
Interface net2:
	(No addresses for this interface)
Interface ppp0:
	(No addresses for this interface)
Interface eth0:
	(No addresses for this interface)
Interface eth1:
	(No addresses for this interface)
Interface eth2:
	(No addresses for this interface)
Interface ppp1:
	(No addresses for this interface)
Interface net3:
	(No addresses for this interface)
Interface eth3:
	Address (v6): fe80:0:0:0:d801:2a2c:c88:70ef%11
	Address (v4): 172.16.15.199
Interface net4:
	Address (v6): fe80:0:0:0:0:5efe:ac10:fc7%12
Interface net5:
	Address (v6): 2001:0:5ef5:79fd:1000:1d40:53ef:f038
	Address (v6): fe80:0:0:0:1000:1d40:53ef:f038%13
Interface eth4:
	(No addresses for this interface)
Interface eth5:
	(No addresses for this interface)
Interface eth6:
	(No addresses for this interface)
Interface eth7:
	(No addresses for this interface)
Interface eth8:
	(No addresses for this interface)
127.0.0.1:
	127.0.0.1/127.0.0.1
localhost:
	localhost/127.0.0.1
	localhost/0:0:0:0:0:0:0:1

InetAddress: 创建和访问

//  getAllByName()    方法用于返回一组与给定主机名相关联的所有地址的实例
static InetAddress[ ] getAllByName(String host) 
//  getAddress()    方法返回一个适当长度的字节数组，代表地址的二进制的形式
static InetAddress getByName(String host) 
static InetAddress getLocalHost() byte[] getAddress()

InetAddress: 字符串表示

String toString() 
String getHostAddress() 
String getHostName() 
String getCanonicalHostName()

InetAddress: 检测属性

boolean isAnyLocalAddress() 
boolean isLinkLocalAddress() 
boolean isLoopbackAddress() 
boolean isMulticastAddress() 
boolean isMCGlobal() 
boolean isMCLinkLocal() 
boolean isMCNodeLocal() 
boolean isMCOrgLocal() 
boolean isMCSiteLocal() 
boolean isReachable(int timeout) 
boolean isReachable(NetworkInterface netif, int ttl, int timeout)

上述前三个方法分别检查地址实例是否属于 " 任意 " 本地地址，本地链接地址，以及回环地址

（匹配 127.*.*.* 或 ::1 的形式）。第 4 个方法检查其是否为一个多播地址，而 isMC...() 形式的方法检测多播地址的各种范围（ scopes ）。最后两个方法检查是否真能与 InetAddress 地址确定的主机进行数据报文交换。

NetworkInterface: 创建，获取信息

static Enumeration<NetworkInterface> getNetworkInterfaces() 
static NetworkInterface getByInetAddress(InetAddress addr) 
static NetworkInterface getByName(String name) 
Enumeration<InetAddress> getInetAddresses() 
String getName()

String getDisplayName()

上面第一个方法非常有用，使用它可以很容易获取到运行程序的主机的 IP 地址：通过 getNetworkInterfaces() 方法可以获取一个接口列表，再使用实例的 getInetAddresses() 方法就可以获取每个接口的所有地址。注意：这个列表包含了主机的所有接口，包括不能够向网络中的其他主机发送或接收消息的虚拟回环接口。同样，列表中可能还包括外部不可达的本地链接地址。由于这些列表都是无序的，所以你不能简单地认为，列表中第一个接口的第一个地址一定能够通过互联网访问，而是要通过前面提到的 InetAddress 类的属性检查方法，来判断一个地址不是回环地址，不是本地链接地址等等。

getName() 方法返回一个接口（ interface ）的名字（不是主机名）。

Java Socket-02 Java Socket地址

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