Ubuntu64 9.04机器上的Java应用程序中的域名解析不起作用。所有其他软件都能正确解析DNS [英] Domain name resolution not working in Java Applications on Ubuntu64 9.04 machine. All other software resolves DNS correctly
问题描述
更新：
我确定我家或办公室没有代理服务器。 - 我感谢你们帮助我在这里我真的想使用Linux而不是Windows，现在我正在进行Java开发。
jgreenwood @ jeg-ubuntu64：〜 $ cat /etc/resolv.conf
＃由NetworkManager生成
domain hsd1.in.comcast.net。
搜索hsd1.in.comcast.net。
nameserver 192.168.0.1
jgreenwood @ jeg-ubuntu64：〜$ env | grep -i proxy
jgreenwood @ jeg-ubuntu64：〜$ dig google.com
; <<>> DiG 9.5.1-P2< google.com
;;全局选项：printcmd
;;得到答案：
;; - >> HEADER< - opcode：QUERY，status：NOERROR，id：56845
;;国旗：qr rd ra; QUERY：1，ANSWER：3，AUTHORITY：0，ADDITIONAL：0
;;问题部分：
; google.com。 IN A
;;答案部分：
google.com。 58 IN A 74.125.53.100
google.com。 58 IN A 74.125.45.100
google.com。 58 IN A 74.125.67.100
;;查询时间：35毫秒
;;服务器：192.168.0.1＃53（192.168.0.1）
;; WHEN：Thu Oct 22 13:37:26 2009
;; MSG SIZE rcvd：76
更新：
我在RAD中写了这个java程序：
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.io.PrintWriter;
import java.io.StringWriter;
public class DomainResolutionTest {
public static void main（String [] args）{
if（args.length == 0）args = new String [] {www.google.com};
try {
InetAddress ip = InetAddress.getByName（args [0]）;
System.out.println（ip.toString（））;
} catch（UnknownHostException uhx）{
System.out.println（ERROR：+ uhx.getMessage（）+\\\
+ getStackTrace（uhx））;
Throwable cause = uhx.getCause（）;
if（cause！= null）System.out.println（CAUSE：+ cause.getMessage（））;
}
}
public static String getStackTrace（Throwable t）
{
StringWriter sw = new StringWriter（）;
PrintWriter pw = new PrintWriter（sw，true）;
t.printStackTrace（pw）;
pw.flush（）;
sw.flush（）;
return sw.toString（）;
}
}
输出是：
错误：www.google.com
java.net.UnknownHostException：www.google.com
在java。 net.Inet6AddressImpl.lookupAllHostAddr（Native Method）
在java.net.InetAddress $ 1.lookupAllHostAddr（InetAddress.java:862）
在java.net.InetAddress.getAddressFromNameService（InetAddress.java:1213）
在java.net.InetAddress.getAllByName0（InetAddress.java:1166）
在java.net.InetAddress.getAllByName（InetAddress.java:1096）
在java.net.InetAddress.getAllByName（InetAddress .java：1032）
在java.net.InetAddress.getByName（InetAddress.java:982）
在DomainResolutionTest.main（DomainResolutionTest.java:12）
从命令行：（相同结果）
jgreenwood @ jeg-ubuntu64：〜$ javac DomainResolutionTest.java/ pre>
jgreenwood @ jeg-ubuntu64：〜$ java DomainResolutionTest
错误：www.google.com
java.net.UnknownHostException：www.google.com
在java.net.Inet6AddressImpl.lookupAllHostAddr（本机方法）
在java.net.InetAddress $ 1.lookupAllHostAddr（InetAddress.java:849 ）
在java.net.InetAddress.getAddressFromNameService（InetAddress.java:1200）
在java.net.InetAddress.getAllByName0（InetAddress.java:1153）
在java.net.InetAddress。 getAllByName（InetAddress.java:1083）
在java.net.InetAddress.getAllByName（InetAddress.java:1019）
在java.net.InetAddress.getByName（InetAddress.java:969）
在DomainResolutionTest.main（DomainResolutionTest.java:12）
jgreenwood @ jeg-ubuntu64：〜$ java -version
java版本1.6.0_16
Java（TM）SE运行时环境1.6.0_16-b01）
Java HotSpot（TM）服务器虚拟机（build 14.2-b01，混合模式）
jgreenwood @ jeg-ubuntu64：〜$
解决方案再次，由于这里的人的指导，我找到了一个答案。以下Java程序在执行以下操作时：
java -Djava.net.preferIPv4Stack = true DomainResolutionTest
详细信息：
jgreenwood @ jeg-ubuntu64：〜$ java -Djava.net.preferIPv4Stack = true DomainResolutionTest
www.google.com/209.85.225.106
jgreenwood @ jeg- ubuntu64：〜$ java DomainResolutionTest错误：www.google.com
java.net.UnknownHostException：www.google.com
在java.net.Inet6AddressImpl.lookupAllHostAddr（本地方法）
在java .net.InetAddress $ 1.lookupAllHostAddr（InetAddress.java:849）
在java.net.InetAddress.getAddressFromNameService（InetAddress.java:1200）
在java.net.InetAddress.getAllByName0（InetAddress.java： 1153）
在java.net.InetAddress.getAllByName（InetAddress.java:1083）
在java.net.InetAddress.getAllByName（InetAddress.java:1019）
在java.net.InetAddress .getByName（InetAddress.java:969）
在DomainReso lutionTest.main（DomainResolutionTest.java:12）
事实证明，IPv6中有一个错误叠加。有几个帖子让我得出这样的结论：
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=477211
https://answers.launchpad.net/ubuntu/+问题/ 23024
我确实希望在每次运行Java应用程序时都不必添加IPv4垃圾邮件。最终的解决方案可能在第二个链接 - 一个丢失的包。我们将看到。
Debian错误报告日志 - ＃477211
ia32-sun-java6-bin：需要依赖于
lib32nss-mdns
...
无法解析域名。在系统的其余部分解决
罚款，
未与其他JDK进行测试。
从包装中安装并设置
update-java-alternatives。
DNS适用于我的
系统上的其他一切。在Debian上运行
2.6.23-AMD64。尝试过Lenny包和Sid包。作为
与sun-java6-bin的预期，$ ia32-sun-java6-bin
失败。精氨酸。 ...如果
你用strace打java，你会看到
它试图使用
libnss_mdns4_minimal.so.2，这是
可用的包
lib32nss-mdns。你应该添加一个
依赖来修复错误。
同样的事情发生在sun-java6-bin -
libnss-mdns被使用
我的机器上确实没有包裹：
jgreenwood @ jeg-ubuntu64：〜$ dpkg -L lib32nss-mdns
未安装lib32nss-mdns包。
使用dpkg --info（= dpkg-deb --info）来检查存档文件
和dpkg --contents（= dpkg-deb --contents）来列出其内容。
无论哪种方式，我希望这篇文章能帮助别人，因为这是一个主要的PITA。
I have an number of Java applications installed on an Ubuntu64 9.04 PC, and none of them can resolve domain names (there are multiple JRE's too - some of them are IBM products). If I put the domain name in the hosts file with it's associated IP address, then the Java apps work for those domains only. Every other non Java program - like ping, firefox, etc - work just fine with domain resolution. I've tried to disable DNS caching in the java.security file - for all of my JREs - but that didn't work either. I would appreciate some help in figuring this one out. Thanks!
UPDATE: I am sure there isn't a proxy server in my home or office. - I appreciate you guys helping me here. I REALLY want to use Linux instead of windows now that I'm doing Java development again.
jgreenwood@jeg-ubuntu64:~$ cat /etc/resolv.conf # Generated by NetworkManager domain hsd1.in.comcast.net. search hsd1.in.comcast.net. nameserver 192.168.0.1 jgreenwood@jeg-ubuntu64:~$ env | grep -i proxy jgreenwood@jeg-ubuntu64:~$ dig google.com ; <<>> DiG 9.5.1-P2 <<>> google.com ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56845 ;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;google.com. IN A ;; ANSWER SECTION: google.com. 58 IN A 74.125.53.100 google.com. 58 IN A 74.125.45.100 google.com. 58 IN A 74.125.67.100 ;; Query time: 35 msec ;; SERVER: 192.168.0.1#53(192.168.0.1) ;; WHEN: Thu Oct 22 13:37:26 2009 ;; MSG SIZE rcvd: 76
UPDATE: I wrote this java program in RAD:
import java.net.InetAddress; import java.net.UnknownHostException; import java.io.PrintWriter; import java.io.StringWriter; public class DomainResolutionTest { public static void main(String[] args) { if (args.length == 0) args = new String[] { "www.google.com" }; try { InetAddress ip = InetAddress.getByName(args[0]); System.out.println(ip.toString()); }catch (UnknownHostException uhx) { System.out.println("ERROR: " + uhx.getMessage() + "\n" + getStackTrace(uhx)); Throwable cause = uhx.getCause(); if (cause != null) System.out.println("CAUSE: " + cause.getMessage()); } } public static String getStackTrace(Throwable t) { StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw, true); t.printStackTrace(pw); pw.flush(); sw.flush(); return sw.toString(); } }The output is:
ERROR: www.google.com java.net.UnknownHostException: www.google.com at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method) at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:862) at java.net.InetAddress.getAddressFromNameService(InetAddress.java:1213) at java.net.InetAddress.getAllByName0(InetAddress.java:1166) at java.net.InetAddress.getAllByName(InetAddress.java:1096) at java.net.InetAddress.getAllByName(InetAddress.java:1032) at java.net.InetAddress.getByName(InetAddress.java:982) at DomainResolutionTest.main(DomainResolutionTest.java:12)
From the command line: (same result)
jgreenwood@jeg-ubuntu64:~$ javac DomainResolutionTest.java jgreenwood@jeg-ubuntu64:~$ java DomainResolutionTest ERROR: www.google.com java.net.UnknownHostException: www.google.com at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method) at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:849) at java.net.InetAddress.getAddressFromNameService(InetAddress.java:1200) at java.net.InetAddress.getAllByName0(InetAddress.java:1153) at java.net.InetAddress.getAllByName(InetAddress.java:1083) at java.net.InetAddress.getAllByName(InetAddress.java:1019) at java.net.InetAddress.getByName(InetAddress.java:969) at DomainResolutionTest.main(DomainResolutionTest.java:12) jgreenwood@jeg-ubuntu64:~$ java -version java version "1.6.0_16" Java(TM) SE Runtime Environment (build 1.6.0_16-b01) Java HotSpot(TM) Server VM (build 14.2-b01, mixed mode) jgreenwood@jeg-ubuntu64:~$
解决方案Once again, thanks to the guidance of the people here, I've found an answer. The Java program above works when I do the following:
java -Djava.net.preferIPv4Stack=true DomainResolutionTest
Details:
jgreenwood@jeg-ubuntu64:~$ java -Djava.net.preferIPv4Stack=true DomainResolutionTest www.google.com/209.85.225.106 jgreenwood@jeg-ubuntu64:~$ java DomainResolutionTest ERROR: www.google.com java.net.UnknownHostException: www.google.com at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method) at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:849) at java.net.InetAddress.getAddressFromNameService(InetAddress.java:1200) at java.net.InetAddress.getAllByName0(InetAddress.java:1153) at java.net.InetAddress.getAllByName(InetAddress.java:1083) at java.net.InetAddress.getAllByName(InetAddress.java:1019) at java.net.InetAddress.getByName(InetAddress.java:969) at DomainResolutionTest.main(DomainResolutionTest.java:12)It turns out that there is a bug in the IPv6 stack. There are a couple of posts that led me to this conclusion:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=477211
https://answers.launchpad.net/ubuntu/+question/23024
I sure hope I don't have to add the IPv4 crap in every time I run a Java app. The final solution may be in the second link - a missing package. We shall see.
Debian Bug report logs - #477211 ia32-sun-java6-bin: Needs to depend on lib32nss-mdns ... Cannot resolve domain names. Resolve fine on the rest of the system, have not tested with other JDK's. Installed from package and set with update-java-alternatives.
DNS works for everything else on my system. Running on Debian 2.6.23-AMD64. Have tried both Lenny packages and Sid packages. Works as expected with sun-java6-bin, fails with ia32-sun-java6-bin. Arg. ... If you hit java with strace you'll see that it is trying to use libnss_mdns4_minimal.so.2, which is available in the package lib32nss-mdns. You should add a dependency on that to fix the bug.
Same thing happens for sun-java6-bin - libnss-mdns is used here.
The package is indeed missing on my machine:
jgreenwood@jeg-ubuntu64:~$ dpkg -L lib32nss-mdns Package `lib32nss-mdns' is not installed. Use dpkg --info (= dpkg-deb --info) to examine archive files, and dpkg --contents (= dpkg-deb --contents) to list their contents.Either way, I hope this post helps someone else, because this was a major PITA to figure out.
这篇关于Ubuntu64 9.04机器上的Java应用程序中的域名解析不起作用。所有其他软件都能正确解析DNS的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
