在Java中获取当前计算机主机名的最方便的方法如下:

import java.net.InetAddress;
import java.net.UnknownHostException;

public class getHostName {

    public static void main(String[] args) throws UnknownHostException {
        InetAddress iAddress = InetAddress.getLocalHost();
        String hostName = iAddress.getHostName();
        //To get  the Canonical host name
        String canonicalHostName = iAddress.getCanonicalHostName();

        System.out.println("HostName:" + hostName);
        System.out.println("Canonical Host Name:" + canonicalHostName);
    }
}

只有一句话……跨平台(Windows-Linux-Unix-Mac(Unix))[始终工作，不需要DNS]:

String hostname = new BufferedReader(
    new InputStreamReader(Runtime.getRuntime().exec("hostname").getInputStream()))
   .readLine();

你完蛋了!!

正如其他人所指出的，根据DNS解析获取主机名是不可靠的。

不幸的是，由于这个问题在2018年仍然相关，我想与大家分享我的网络独立解决方案，并在不同的系统上进行一些测试。

下面的代码尝试执行以下操作:

在Windows上 通过System.getenv()读取环境变量COMPUTERNAME。 执行hostname.exe并读取响应 在Linux上 通过System.getenv()读取HOSTNAME环境变量 执行主机名并读取响应 读取/etc/hostname(要做到这一点，我执行cat，因为代码段已经包含要执行和读取的代码。不过，简单地阅读文件会更好)。

代码:

public static void main(String[] args) throws IOException {
    String os = System.getProperty("os.name").toLowerCase();

    if (os.contains("win")) {
        System.out.println("Windows computer name through env:\"" + System.getenv("COMPUTERNAME") + "\"");
        System.out.println("Windows computer name through exec:\"" + execReadToString("hostname") + "\"");
    } else if (os.contains("nix") || os.contains("nux") || os.contains("mac os x")) {
        System.out.println("Unix-like computer name through env:\"" + System.getenv("HOSTNAME") + "\"");
        System.out.println("Unix-like computer name through exec:\"" + execReadToString("hostname") + "\"");
        System.out.println("Unix-like computer name through /etc/hostname:\"" + execReadToString("cat /etc/hostname") + "\"");
    }
}

public static String execReadToString(String execCommand) throws IOException {
    try (Scanner s = new Scanner(Runtime.getRuntime().exec(execCommand).getInputStream()).useDelimiter("\\A")) {
        return s.hasNext() ? s.next() : "";
    }
}

不同操作系统的结果:

macOS 10 .13.2

Unix-like computer name through env:"null"
Unix-like computer name through exec:"machinename
"
Unix-like computer name through /etc/hostname:""

OpenSuse 13.1

Unix-like computer name through env:"machinename"
Unix-like computer name through exec:"machinename
"
Unix-like computer name through /etc/hostname:""

Ubuntu 14.04 LTS 这个有点奇怪，因为echo $HOSTNAME返回正确的主机名，但是System.getenv("HOSTNAME")没有:

Unix-like computer name through env:"null"
Unix-like computer name through exec:"machinename
"
Unix-like computer name through /etc/hostname:"machinename
"

编辑:根据legolas108, System.getenv("HOSTNAME")在Ubuntu 14.04上工作，如果你在执行Java代码之前运行export HOSTNAME。

Windows 7

Windows computer name through env:"MACHINENAME"
Windows computer name through exec:"machinename
"

Windows 10

Windows computer name through env:"MACHINENAME"
Windows computer name through exec:"machinename
"

机器名称已被替换，但我保留了大写和结构。注意在执行主机名时额外的换行符，在某些情况下可能必须考虑到它。

环境变量也可以提供有用的方法——Windows上的COMPUTERNAME，大多数现代Unix/Linux shell上的HOSTNAME。

参见:https://stackoverflow.com/a/17956000/768795

我使用这些作为InetAddress.getLocalHost(). gethostname()的“补充”方法，因为正如一些人指出的那样，该函数不能在所有环境中工作。

Runtime.getRuntime().exec("hostname")是另一个可能的补充。在这个阶段，我还没有用过它。

import java.net.InetAddress;
import java.net.UnknownHostException;

// try InetAddress.LocalHost first;
//      NOTE -- InetAddress.getLocalHost().getHostName() will not work in certain environments.
try {
    String result = InetAddress.getLocalHost().getHostName();
    if (StringUtils.isNotEmpty( result))
        return result;
} catch (UnknownHostException e) {
    // failed;  try alternate means.
}

// try environment properties.
//      
String host = System.getenv("COMPUTERNAME");
if (host != null)
    return host;
host = System.getenv("HOSTNAME");
if (host != null)
    return host;

// undetermined.
return null;

在Java中获取当前计算机主机名的最方便的方法如下:

import java.net.InetAddress;
import java.net.UnknownHostException;

public class getHostName {

    public static void main(String[] args) throws UnknownHostException {
        InetAddress iAddress = InetAddress.getLocalHost();
        String hostName = iAddress.getHostName();
        //To get  the Canonical host name
        String canonicalHostName = iAddress.getCanonicalHostName();

        System.out.println("HostName:" + hostName);
        System.out.println("Canonical Host Name:" + canonicalHostName);
    }
}

hostName == null;
Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
{
    while (interfaces.hasMoreElements()) {
        NetworkInterface nic = interfaces.nextElement();
        Enumeration<InetAddress> addresses = nic.getInetAddresses();
        while (hostName == null && addresses.hasMoreElements()) {
            InetAddress address = addresses.nextElement();
            if (!address.isLoopbackAddress()) {
                hostName = address.getHostName();
            }
        }
    }
}