【发布时间】：2009-09-04 09:45:41
【问题描述】：
我已经阅读了关于How to download and save a file from internet using Java 的精彩讨论。但是，如果我执行下一个代码，我会得到一个损坏的 PDF。知道为什么吗？
import java.io.*;
import java.net.*;
public class PDFDownload {
public static String URL = "http://www.nbc.com/Heroes/novels/downloads/";
public static String FOLDER = "C:/Users/sdelamo/workspace/SandBox/HeroesNovel/";
public static void main(String[] args) {
String filename = "Heroes_novel_001.pdf";
try {
saveUrl(FOLDER + filename, URL + filename);
} catch (MalformedURLException e) {
System.out.println("MalformedURLException");
} catch (IOException e) {
System.out.println("IOException");
}
}
public static void saveUrl(String filename, String urlString) throws MalformedURLException, IOException {
BufferedInputStream in = null;
FileOutputStream fout = null;
try {
URL url = new URL(urlString);
in = new BufferedInputStream(url.openStream());
fout = new FileOutputStream(filename);
byte data[] = new byte[1024];
int count;
while ((count = in.read(data, 0, 1024)) != -1) {
fout.write(data, 0, count);
}
} finally {
if (in != null)
in.close();
if (fout != null)
fout.close();
}
}
}
以上代码下载的是 html 而不是 PDF。这是输出：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.1//EN"
"http://www.w3.org/TR/xhtml-basic/xhtml-basic11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta name="viewport" content="width=240, user-scalable=yes" />
<HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE">
<META HTTP-EQUIV="Expires" CONTENT="-1">
<meta http-equiv="Cache-control" content="no-cache">
<meta http-equiv="Cache-control" content="must-revalidate">
<meta http-equiv="Cache-control" content="max-age=0">
<meta http-equiv="refresh" content="200">
<title>NBC.com: Heroes</title>
<link rel="stylesheet" type="text/css" href="/style/default.css?sid=8a9212f822e1c675330ec418bc531169" />
<link rel="stylesheet" type="text/css" href="/style/hro.css?sid=8a9212f822e1c675330ec418bc531169" />
</head>
<body>
<center><img src="http://oimg.nbcuni.com/b/ss/nbcunbcnetworkwapbu,nbcuwapsitebu/5/H.8--WAP/4aa0e4cb8b448?vid=8a9212f822e1c675330ec418bc531169&gn=NBC.com Front Door&c2=&c3=Miscellaneous&c4=&c6=m.nbc.com/show/hro&c8=TV Entertainment&c9=NBC Network&c10=&c11= | &c12= | &c25=offdeck&c27=internal&c29=&c44=D=User-Agent&r=" width="5" height="5" border="0" /></center>
<h1 id="fHeader">
<a href="/?sid=8a9212f822e1c675330ec418bc531169">
<img src="/images/nbc_logo.gif" alt="NBC : logo" border="0" />
</a>
</h1>
<h2>
<a href="/show/hro?sid=8a9212f822e1c675330ec418bc531169">
<img src="/images/shows/1221684699_Heroes_WAP_166x54.jpg" alt="Heroes : showheader" border="0" />
</a>
</h2>
<div id="tunein_nexton">
<span id="tunein">Mondays 9/8c</span>
</div><!--end #tunein_nexton-->
<div id="tunein_nexton">
<!--<span id="tunein">Mondays 8/7c</span>-->
<p id="nexton"><span class="sectiontitle"></span></p>
</div><!--end #tunein_nexton-->
<div id="featuredcontent">
<h3>FEATURED CONTENT</h3>
<table id="featuredItemsTable">
<tr>
<td><a href="/show/hro/videos.html?sid=8a9212f822e1c675330ec418bc531169"><img src="/images/hro/nbc_hro_pro_040X921HRO120FLYPSIDE_exp921_20090_543_large.jpg" alt="featured" /></a>
</td>
<td>
<span class="ftitle">Dreams</span>
<span class="fdesc">Heroes premieres Mon., Sept. 21s...</span>
</td>
</tr>
<tr>
<td><a href="/show/hro/recaps.html?sid=8a9212f822e1c675330ec418bc531169"><img src="http://origin-www.nbc.com/Heroes/images/episodes/season3/325/hro_325_01.jpg" alt="featured" height="45" width="80"/></a>
</td>
<td>
<span class="ftitle">Recap:</span>
<span class="fdesc">Season 3 Episode An Invisible Thread</span>
</td>
</tr>
<tr>
<td><a href="/show/hro/photos.html?sid=8a9212f822e1c675330ec418bc531169"><img src="http://origin-www.nbc.com/app2/img/200x200xS/scet/photos/51/3736/NUP_110031_0323.JPG" alt="featured" height="45" width="80"/></a>
</td>
<td class="finfo">
<span class="ftitle">Photo:</span>
<span class="fdesc">Heroes "Cast Photos"</span>
</td>
</tr>
</table>
</div><!--end #featuredcontent-->
<h3>HEROES</h3>
<table class="showNav">
<tr><td><a href="/show/hro/about.html?sid=8a9212f822e1c675330ec418bc531169" accesskey="1">About</a></td></tr>
<tr><td><a href="/show/hro/videos.html?sid=8a9212f822e1c675330ec418bc531169" accesskey="2">Videos</a></td></tr>
<tr><td><a href="/show/hro/recaps.html?sid=8a9212f822e1c675330ec418bc531169" accesskey="3">Episode Recaps</a></td></tr>
<tr><td><a href="/show/hro/photos.html?sid=8a9212f822e1c675330ec418bc531169" accesskey="4">Photos</a></td></tr>
<tr><td><a href="/show/hro/community.html?sid=8a9212f822e1c675330ec418bc531169" accesskey="5">Community</a></td></tr>
<tr><td><a href="/shows.shtml?sid=8a9212f822e1c675330ec418bc531169" accesskey="6">Shows List</a></td></tr>
</table>
<!-- <a href="http://www.insightexpress.com/ix/Survey.aspx?id=151580&accessCode=3161643404&sid=8a9212f822e1c675330ec418bc531169" ><img src="/images/mNBCcom_166x54.jpg" border="0"></a> -->
<div class="footer" align="center"><a href="http://m.nbc.com?sid=8a9212f822e1c675330ec418bc531169"><strong>NBC Mobile Main</strong></a> | <a href="/terms.shtml?sid=8a9212f822e1c675330ec418bc531169"><strong>Terms of Use</strong></a> | <a href="/privacy.shtml?sid=8a9212f822e1c675330ec418bc531169"><strong>Privacy</strong></a></div><div class="cpyrt" align="center">© NBC Universal, Inc.</div>
</body>
</html>
知道如何下载 PDF 吗？
解决方案
在连接前设置 User-Agent。
URL u = new URL(urlString);
HttpURLConnection huc = (HttpURLConnection) u.openConnection();
huc.setRequestMethod("GET");
huc.setRequestProperty("User-Agent", " Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)");
huc.connect();
in = new BufferedInputStream(huc.getInputStream());
【问题讨论】：