blocks|key|2951863|text|如果您的IP地址是127.0.0.1，那么您可能需要定位您的操作系统特定主机文件，并在其中添加一个映射到您的主机名。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2951864|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

If you are getting 127.0.0.1 as the IP address then you may need to locate your Operating System specific hosts file and add a mapping to your hostname in it.

blocks|key|1396328|text|这是个小问题。但是您可以从Java启动一个新进程并运行hostname命令。读取子进程的输出流将给出本地主机的名称。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1396329|entityMap^0|R|8|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

This is a bit of a hack. But you could launch a new Process from Java and run the <code>hostname</code> command. Reading the outputstream of the child process would give you the name of the localhost.

blocks|key|2593651|text|是的，在Java中应该有一种获得主机名的方法，而无需使用命名服务查找，但不幸的是，没有。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2593652|但是，您可以这样做：|2593653|if+(System.getProperty("os.name").startsWith("Windows"))+{
++++//+Windows+will+always+set+the+'COMPUTERNAME'+variable
++++return+System.getenv("COMPUTERNAME");
}+else+{
++++//+If+it+is+not+Windows+then+it+is+most+likely+a+Unix-like+operating+system
++++//+such+as+Solaris,+AIX,+HP-UX,+Linux+or+MacOS.

++++//+Most+modern+shells+(such+as+Bash+or+derivatives)+sets+the+
++++//+HOSTNAME+variable+so+lets+try+that+first.
++++String+hostname+=+System.getenv("HOSTNAME");
++++if+(hostname+!=+null)+{
+++++++return+hostname;
++++}+else+{

+++++++//+If+the+above+returns+null+*and*+the+OS+is+Unix-like
+++++++//+then+you+can+try+an+exec()+and+read+the+output+from+the+
+++++++//+'hostname'+command+which+exist+on+all+types+of+Unix/Linux.

+++++++//+If+you+are+an+OS+other+than+Unix/Linux+then+you+would+have+
+++++++//+to+do+something+else.+For+example+on+OpenVMS+you+would+find+
+++++++//+it+like+this+from+the+shell:++F$GETSYI("NODENAME")+
+++++++//+which+you+would+probably+also+have+to+find+from+within+Java+
+++++++//+via+an+exec()+call.

+++++++//+If+you+are+on+zOS+then+who+knows+??

+++++++//+etc,+etc
++++}
}|code-block|syntax|javascript|2593654|在传统的Sun平台(Windows、Solaris、Linux)上，这将给您带来100%25的需求，但是如果操作系统更外接(从Java的角度来看)，就会变得不那么容易了。请参阅代码示例中的注释。|2593655|我希望有更好的方法。|2593656|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Yes, there should be a way in Java to get the hostname without resorting to name service lookups but unfortunately there isn't.

However, you can do something like this:

<pre><code>if (System.getProperty("os.name").startsWith("Windows")) {
 // Windows will always set the 'COMPUTERNAME' variable
 return System.getenv("COMPUTERNAME");
} else {
 // If it is not Windows then it is most likely a Unix-like operating system
 // such as Solaris, AIX, HP-UX, Linux or MacOS.

 // Most modern shells (such as Bash or derivatives) sets the 
 // HOSTNAME variable so lets try that first.
 String hostname = System.getenv("HOSTNAME");
 if (hostname != null) {
 return hostname;
 } else {

 // If the above returns null *and* the OS is Unix-like
 // then you can try an exec() and read the output from the 
 // 'hostname' command which exist on all types of Unix/Linux.

 // If you are an OS other than Unix/Linux then you would have 
 // to do something else. For example on OpenVMS you would find 
 // it like this from the shell: F$GETSYI("NODENAME") 
 // which you would probably also have to find from within Java 
 // via an exec() call.

 // If you are on zOS then who knows ??

 // etc, etc
 }
}
</code></pre>

and that will get you 100% what you want on the traditional Sun JDK platforms (Windows, Solaris, Linux) but becomes less easy if your OS is more excotic (from a Java perspective). See the comments in the code example.

I wish there was a better way.

blocks|key|1396380|text|如果没有配置DNS，Java将读取/etc/host文件，或者更确切地说，读取相应的C函数。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1396381|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Java will read the /etc/hosts file if there is no DNS configured, or rather the corresponding C functions will.

blocks|key|1396421|text|这个问题由来已久，但不幸的是，仍然与此相关，因为在Java中获取机器的主机名仍然不是件容易的事。下面是我在不同系统上运行一些测试的解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1396422|public+static+void+main(String[]+args)+throws+IOException+{
++++++++String+OS+=+System.getProperty("os.name").toLowerCase();

++++++++if+(OS.indexOf("win")+>=+0)+{
++++++++++++System.out.println("Windows+computer+name+throguh+env:\""+%2B+System.getenv("COMPUTERNAME")+%2B+"\"");
++++++++++++System.out.println("Windows+computer+name+through+exec:\""+%2B+execReadToString("hostname")+%2B+"\"");
++++++++}+else+{
++++++++++++if+(OS.indexOf("nix")+>=+0+%7C%7C+OS.indexOf("nux")+>=+0)+{
++++++++++++++++System.out.println("Linux+computer+name+throguh+env:\""+%2B+System.getenv("HOSTNAME")+%2B+"\"");
++++++++++++++++System.out.println("Linux+computer+name+through+exec:\""+%2B+execReadToString("hostname")+%2B+"\"");
++++++++++++++++System.out.println("Linux+computer+name+through+/etc/hostname:\""+%2B+execReadToString("cat+/etc/hostname")+%2B+"\"");
++++++++++++}
++++++++}
++++}

++++public+static+String+execReadToString(String+execCommand)+throws+IOException+{
++++++++Process+proc+=+Runtime.getRuntime().exec(execCommand);
++++++++try+(InputStream+stream+=+proc.getInputStream())+{
++++++++++++try+(Scanner+s+=+new+Scanner(stream).useDelimiter("\\A"))+{
++++++++++++++++return+s.hasNext()+?+s.next()+:+"";
++++++++++++}
++++++++}
++++}|code-block|syntax|javascript|1396423|不同操作系统的结果：|1396424|OpenSuse+13.1|offset|length|style|BOLD|1396425|Linux+computer+name+throguh+env:"machinename"
Linux+computer+name+through+exec:"machinename
"
Linux+computer+name+through+/etc/hostname:""|1396426|Ubuntu14.04LTS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(不过，这可能只是我的环境中的一个问题)：|CODE|1396427|Linux+computer+name+throguh+env:"null"
Linux+computer+name+through+exec:"machinename
"
Linux+computer+name+through+/etc/hostname:"machinename
"|1396428|Windows+7|1396429|Windows+computer+name+throguh+env:"MACHINENAME"
Windows+computer+name+through+exec:"machinename
"|1396430|机器名称已被替换为(一些)匿名化，但我保留了大写和结构。注意，在执行hostname时需要额外的换行符，在某些情况下可能需要考虑到它。|1396431|entityMap^0|0|0|0|0|D|0|0|0|E|N|E|1C|P|0|0|0|9|0|0|Y|8|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|14|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|15|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|16|8|@$K|17|L|18|M|N]]|9|@]|A|$]]|$1|O|3|P|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|1A|8|@$K|1B|L|1C|M|N]|$K|1D|L|1E|M|S]|$K|1F|L|1G|M|S]]|9|@]|A|$]]|$1|T|3|U|5|D|7|1H|8|@]|9|@]|A|$E|F]]|$1|V|3|W|5|6|7|1I|8|@$K|1J|L|1K|M|N]]|9|@]|A|$]]|$1|X|3|Y|5|D|7|1L|8|@]|9|@]|A|$E|F]]|$1|Z|3|10|5|6|7|1M|8|@$K|1N|L|1O|M|S]]|9|@]|A|$]]|$1|11|3|-4|5|6|7|1P|8|@]|9|@]|A|$]]]|12|$]]

This question is old, but unfortunately still relevant since it's still not trivial to get a machine's host name in Java. Here's my solution with some test runs on different systems:

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

 if (OS.indexOf("win") &gt;= 0) {
 System.out.println("Windows computer name throguh env:\"" + System.getenv("COMPUTERNAME") + "\"");
 System.out.println("Windows computer name through exec:\"" + execReadToString("hostname") + "\"");
 } else {
 if (OS.indexOf("nix") &gt;= 0 || OS.indexOf("nux") &gt;= 0) {
 System.out.println("Linux computer name throguh env:\"" + System.getenv("HOSTNAME") + "\"");
 System.out.println("Linux computer name through exec:\"" + execReadToString("hostname") + "\"");
 System.out.println("Linux computer name through /etc/hostname:\"" + execReadToString("cat /etc/hostname") + "\"");
 }
 }
 }

 public static String execReadToString(String execCommand) throws IOException {
 Process proc = Runtime.getRuntime().exec(execCommand);
 try (InputStream stream = proc.getInputStream()) {
 try (Scanner s = new Scanner(stream).useDelimiter("\\A")) {
 return s.hasNext() ? s.next() : "";
 }
 }
 }
</code></pre>

Results for different operating systems:

OpenSuse 13.1

<pre><code>Linux computer name throguh env:"machinename"
Linux computer name through exec:"machinename
"
Linux computer name through /etc/hostname:""
</code></pre>

Ubuntu 14.04 LTS 
This one is kinda strange since <code>echo $HOSTNAME</code> returns the correct hostname, but <code>System.getenv("HOSTNAME")</code> does not (this however might be an issue with my environment only):

<pre><code>Linux computer name throguh env:"null"
Linux computer name through exec:"machinename
"
Linux computer name through /etc/hostname:"machinename
"
</code></pre>

Windows 7

<pre><code>Windows computer name throguh env:"MACHINENAME"
Windows computer name through exec:"machinename
"
</code></pre>

The machine names have been replaced for (some) anonymization, but I've kept the capitalization and structure. Note the extra newline when executing <code>hostname</code>, you might have to take it into account in some cases.

blocks|key|1396454|text|或者，使用南国防军调用unixes上的gethostname函数，避免反向DNS查找。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1396455|注意:在Linux上，我相信gethostname只是调用uname并解析输出。在OS上，情况更复杂，因为主机名可能会受到DNS的影响，但除了这些副作用之外，这肯定是我从hostname得到的。|1396456|import+com.sun.jna.LastErrorException
import+com.sun.jna.Library
import+com.sun.jna.Native

...

private+static+final+C+c+=+(C)+Native.loadLibrary("c",+C.class);

private+static+interface+C+extends+Library+{
++++public+int+gethostname(byte[]+name,+int+size_t)+throws+LastErrorException;
}

public+String+getHostName()+{
++++byte[]+hostname+=+new+byte[256];
++++c.gethostname(hostname,+hostname.length)
++++return+Native.toString(hostname)
}|code-block|syntax|javascript|1396457|jna-platform.jar包含Win32函数，因此它就像对Kernel32Util.getComputerName()的调用一样简单。|1396458|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/twall/jna/^0|J|B|5|4|0|0|E|B|T|5|2D|8|0|0|0|G|W|U|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|F|3|G|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]|$9|17|A|18|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|19|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1A|8|@$9|1B|A|1C|B|C]|$9|1D|A|1E|B|C]]|D|@]|E|$]]|$1|O|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

Alternatively, use <a href="https://github.com/twall/jna/" rel="nofollow">JNA</a> to call the <code>gethostname</code> function on unixes, avoiding the reverse DNS lookup.

Some notes: on Linux, I believe <code>gethostname</code> simply calls <code>uname</code> and parses the output. On OS X the situation is more complex, as your hostname can be affected by DNS, but those side-effects aside, it's definitely what I get from <code>hostname</code>.

<pre><code>import com.sun.jna.LastErrorException
import com.sun.jna.Library
import com.sun.jna.Native

...

private static final C c = (C) Native.loadLibrary("c", C.class);

private static interface C extends Library {
 public int gethostname(byte[] name, int size_t) throws LastErrorException;
}

public String getHostName() {
 byte[] hostname = new byte[256];
 c.gethostname(hostname, hostname.length)
 return Native.toString(hostname)
}
</code></pre>

<code>jna-platform.jar</code> includes Win32 functions, so there it's as simple as a call to <code>Kernel32Util.getComputerName()</code>.

blocks|key|2593778|text|在Linux上读|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2593779|/proc/sys/kernel/hostname|code-block|syntax|javascript|2593780|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

on Linux read 

<pre><code>/proc/sys/kernel/hostname
</code></pre>

blocks|key|2593808|text|如果您不反对使用来自maven中心的外部依赖，我编写了gethostname4j来解决这个问题。它只使用JNA调用libc的gethostname函数(或在Windows上获取ComputerName+)并将其作为字符串返回给您。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2593809|https://github.com/mattsheppard/gethostname4j|offset|length|2593810|(我认为这几乎正是丹尼-托马斯提议的，但如果你已经在使用Maven，也许会更方便。)|2593811|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|19|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@$D|Q|E|R|1|S]]|A|$]]|$1|F|3|G|5|6|7|T|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|C]]]]

If you're not against using an external dependency from maven central, I wrote gethostname4j to solve this problem for myself. It just uses JNA to call libc's gethostname function (or gets the ComputerName on Windows) and returns it to you as a string.

<a href="https://github.com/mattsheppard/gethostname4j" rel="nofollow noreferrer">https://github.com/mattsheppard/gethostname4j</a>

(I think it's almost exactly what @danny-thomas proposed, but maybe more convenient if you're already using Maven ;)

This sounds like something that should have been asked before, and it has sort of, but I'm looking to get the local hostname and IP addresses of a machine even when it is not resolvable through DNS (in Java). 

I can get the local IP addresses without resolution by iterating through <code>NetworkInterfaces.getNetworkInterfaces()</code>. 

Any answers to this question I've found indicate to use getLocalHost() 

<pre><code>InetAddress localhost = java.net.InetAddress.getLocalHost();
hostName = localhost.getHostName();
</code></pre>

but this throws an <code>UnknownHostException</code> if the hostname isn't resolvable through DNS. 

Is there no way to get the local hostname without a DNS lookup happening behind the scenes?

edit: the IP address retrieved is 10.4.168.23
The exception is <code>java.net.UnknownHostException: cms1.companyname.com: cms1.companyname.com</code> (hostname changed for pseudo-anonymity), and the hosts file does not contain the hostname. But it does know its hostname, so I'm not sure why I can't get it without an exception being thrown.

How do I get the local hostname if unresolvable through DNS in Java?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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这听起来像是以前应该问过的问题，但我希望获得机器的本地主机名和IP地址，即使它无法通过DNS (在Java中)解析。我可以通过迭代NetworkInterfaces.getNetworkInterfaces()获得本地IP地址，而不需要解析。我发现的对这个问题的任何回答都表明使用getLocalHost()InetAd...

问如果无法通过Java中的DNS解析，如何获得本地主机名？
EN

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问如果无法通过Java中的DNS解析，如何获得本地主机名？EN

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问如果无法通过Java中的DNS解析，如何获得本地主机名？
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