使用HttpClient和iText下载slideshare上的文档

1、使用HttpClient获取页面HTML
2、解析HTML获取最大页数和第一页的图像地址
3、分别抓取各页的图像
4、使用iText将所有页面的图像做成PDF

前提是需FQ(PacketiX VPN)

	private static final String SD_URL = "http://www.slideshare.net/ProphetsAgency/trends-in-interactive-design-2013";
	private static final String OUT_PUT_FOLDER = "C:\\sd\\";
	private static final String PDF_NAME = "trends-in-interactive-design-2013.pdf";

	public static void main(String[] args) throws Exception {
		// Get HTML
		HttpClient client = new DefaultHttpClient();
		HttpGet get = new HttpGet(SD_URL);
		HttpResponse res = client.execute(get);
		
		if (res.getEntity() != null) {
			String htmldata = EntityUtils.toString(res.getEntity());
			
			int maxpage = 0;
			String imgurl = "";
			List<String> fileNameList = new ArrayList<String>();
			
			// Get max page
			Pattern dataPattern = Pattern.compile("<span>/(.+)</span>", Pattern.CASE_INSENSITIVE);
			Matcher tagMatcher = dataPattern.matcher(htmldata);
			if (tagMatcher.find()) {
				maxpage  = Integer.parseInt(tagMatcher.group(1));
			}
			
			// Get the first page image's URL
			Pattern dataPattern2 = Pattern.compile("background-image:url\\(\\'(.+)\\?.+\\'\\)", Pattern.CASE_INSENSITIVE);
			Matcher tagMatcher2 = dataPattern2.matcher(htmldata);
			if (tagMatcher2.find()) {
				imgurl = tagMatcher2.group(1);
			}

			System.out.println("maxpage:" + maxpage);
			
			// Get all page images to local
			for (int i = 1; i <= maxpage; i++) {
				String[] uriArray = imgurl.split("/");
				
				String filename = uriArray[uriArray.length-1];
				String[] nameArray = filename.split("-");
				filename = nameArray[0] + "-" + i + "-" + nameArray[2];
				
				imgurl = imgurl.substring(0,imgurl.lastIndexOf("/")) + "/" + filename;
				
				getUrlImg(imgurl, OUT_PUT_FOLDER + filename);

				System.out.println("imgurl:" + imgurl);
				fileNameList.add(filename);
			}
			
			// Create PDF
			Rectangle rect = new Rectangle(PageSize.B5.rotate());
			Document document = new Document(rect);
			PdfWriter.getInstance(document, new FileOutputStream(OUT_PUT_FOLDER + PDF_NAME));
			document.open();
			for (int i = 0; i < fileNameList.size(); i++) {
				if (i != 0) {
					document.newPage();
				}
				Image img = Image.getInstance(OUT_PUT_FOLDER + fileNameList.get(i));
				img.setAlignment(Image.TOP);
	            document.add(img);
			}
			document.close();
			
		}
		EntityUtils.consume(res.getEntity());
		client.getConnectionManager().shutdown();
	}
	
	public static void getUrlImg(String URLName, String target) throws Exception {
		URL url = new URL(URLName);
		URLConnection urlconn = url.openConnection();
		HttpURLConnection httpconn = (HttpURLConnection) urlconn;		
		int HttpResult = httpconn.getResponseCode();		
		if (HttpResult != HttpURLConnection.HTTP_OK) {
			System.out.print("fail");
			return;
		}	
		BufferedInputStream bis = new BufferedInputStream(urlconn.getInputStream());
		BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(target));
		byte[] buffer = new byte[1024];
		int num = -1;
		while (true) {
			num = bis.read(buffer);
			if (num == -1) {
				bos.flush();
				break;
			}
			bos.flush();
			bos.write(buffer, 0, num);
		}
		bos.close();
		bis.close();
	}