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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head><meta http-equiv="content-type" content="text/html; charset=UTF-8" /><title>DNSJavaUtil xref</title><link type="text/css" rel="stylesheet" href="../../../stylesheet.css" /></head><body><div id="overview"><a href="../../../../apidocs/org/archive/util/DNSJavaUtil.html">View Javadoc</a></div><pre><a name="1" href="#1">1</a> <em class="comment">/*<em class="comment"> DNSJavaUtil</em></em><a name="2" href="#2">2</a> <em class="comment"> * </em><a name="3" href="#3">3</a> <em class="comment"> * Created on Oct 8, 2004</em><a name="4" href="#4">4</a> <em class="comment"> *</em><a name="5" href="#5">5</a> <em class="comment"> * Copyright (C) 2004 Internet Archive.</em><a name="6" href="#6">6</a> <em class="comment"> * </em><a name="7" href="#7">7</a> <em class="comment"> * This file is part of the Heritrix web crawler (crawler.archive.org).</em><a name="8" href="#8">8</a> <em class="comment"> * </em><a name="9" href="#9">9</a> <em class="comment"> * Heritrix is free software; you can redistribute it and/or modify</em><a name="10" href="#10">10</a> <em class="comment"> * it under the terms of the GNU Lesser Public License as published by</em><a name="11" href="#11">11</a> <em class="comment"> * the Free Software Foundation; either version 2.1 of the License, or</em><a name="12" href="#12">12</a> <em class="comment"> * any later version.</em><a name="13" href="#13">13</a> <em class="comment"> * </em><a name="14" href="#14">14</a> <em class="comment"> * Heritrix is distributed in the hope that it will be useful, </em><a name="15" href="#15">15</a> <em class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</em><a name="16" href="#16">16</a> <em class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</em><a name="17" href="#17">17</a> <em class="comment"> * GNU Lesser Public License for more details.</em><a name="18" href="#18">18</a> <em class="comment"> * </em><a name="19" href="#19">19</a> <em class="comment"> * You should have received a copy of the GNU Lesser Public License</em><a name="20" href="#20">20</a> <em class="comment"> * along with Heritrix; if not, write to the Free Software</em><a name="21" href="#21">21</a> <em class="comment"> * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA</em><a name="22" href="#22">22</a> <em class="comment"> */</em><a name="23" href="#23">23</a> <strong>package</strong> <a href="../../../org/archive/util/package-summary.html">org.archive.util</a>;<a name="24" href="#24">24</a> <a name="25" href="#25">25</a> <strong>import</strong> java.net.InetAddress;<a name="26" href="#26">26</a> <a name="27" href="#27">27</a> <strong>import</strong> org.xbill.DNS.ARecord;<a name="28" href="#28">28</a> <strong>import</strong> org.xbill.DNS.DClass;<a name="29" href="#29">29</a> <strong>import</strong> org.xbill.DNS.Record;<a name="30" href="#30">30</a> <strong>import</strong> org.xbill.DNS.TextParseException;<a name="31" href="#31">31</a> <strong>import</strong> org.xbill.DNS.Type;<a name="32" href="#32">32</a> <strong>import</strong> org.xbill.DNS.Lookup;;<a name="33" href="#33">33</a> <a name="34" href="#34">34</a> <em>/**<em>*</em></em><a name="35" href="#35">35</a> <em> * Utility methods based on DNSJava.</em><a name="36" href="#36">36</a> <em> * Use these utilities to avoid having to use the native InetAddress lookup.</em><a name="37" href="#37">37</a> <em> * @author stack</em><a name="38" href="#38">38</a> <em> * @version $Date: 2007-01-06 05:17:35 +0000 (Sat, 06 Jan 2007) $, $Revision: 4837 $</em><a name="39" href="#39">39</a> <em> */</em><a name="40" href="#40">40</a> <strong>public</strong> <strong>class</strong> <a href="../../../org/archive/util/DNSJavaUtil.html">DNSJavaUtil</a> {<a name="41" href="#41">41</a> <strong>private</strong> <a href="../../../org/archive/util/DNSJavaUtil.html">DNSJavaUtil</a>() {<a name="42" href="#42">42</a> <strong>super</strong>();<a name="43" href="#43">43</a> }<a name="44" href="#44">44</a> <a name="45" href="#45">45</a> <em>/**<em>*</em></em><a name="46" href="#46">46</a> <em> * Return an InetAddress for passed <code>host</code>.</em><a name="47" href="#47">47</a> <em> * </em><a name="48" href="#48">48</a> <em> * If passed host is an IPv4 address, we'll not do a DNSJava</em><a name="49" href="#49">49</a> <em> * lookup.</em><a name="50" href="#50">50</a> <em> * </em><a name="51" href="#51">51</a> <em> * @param host Host to lookup in dnsjava.</em><a name="52" href="#52">52</a> <em> * @return A host address or null if not found.</em><a name="53" href="#53">53</a> <em> */</em><a name="54" href="#54">54</a> <strong>public</strong> <strong>static</strong> InetAddress getHostAddress(String host) {<a name="55" href="#55">55</a> InetAddress hostAddress = InetAddressUtil.getIPHostAddress(host);<a name="56" href="#56">56</a> <strong>if</strong> (hostAddress != <strong>null</strong>) {<a name="57" href="#57">57</a> <strong>return</strong> hostAddress;<a name="58" href="#58">58</a> }<a name="59" href="#59">59</a> <a name="60" href="#60">60</a> <em class="comment">// Ask dnsjava for the inetaddress. Should be in its cache.</em><a name="61" href="#61">61</a> Record[] rrecordSet;<a name="62" href="#62">62</a> <strong>try</strong> {<a name="63" href="#63">63</a> rrecordSet = (<strong>new</strong> Lookup(host, Type.A, DClass.IN)).run();<a name="64" href="#64">64</a> } <strong>catch</strong> (TextParseException e) {<a name="65" href="#65">65</a> rrecordSet = <strong>null</strong>;<a name="66" href="#66">66</a> }<a name="67" href="#67">67</a> <strong>if</strong> (rrecordSet != <strong>null</strong>) {<a name="68" href="#68">68</a> <em class="comment">// Get TTL and IP info from the first A record (there may be</em><a name="69" href="#69">69</a> <em class="comment">// multiple, e.g. www.washington.edu).</em><a name="70" href="#70">70</a> <strong>for</strong> (<strong>int</strong> i = 0; i < rrecordSet.length; i++) {<a name="71" href="#71">71</a> <strong>if</strong> (rrecordSet[i].getType() != Type.A) {<a name="72" href="#72">72</a> <strong>continue</strong>;<a name="73" href="#73">73</a> }<a name="74" href="#74">74</a> hostAddress = ((ARecord)rrecordSet[i]).getAddress();<a name="75" href="#75">75</a> <strong>break</strong>;<a name="76" href="#76">76</a> }<a name="77" href="#77">77</a> }<a name="78" href="#78">78</a> <strong>return</strong> hostAddress;<a name="79" href="#79">79</a> }<a name="80" href="#80">80</a> }</pre></html>?? 快捷鍵說明
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