java - jsoup 从 amazon.com 链接爬取图像宽度和高度

Question

以下是我尝试抓取图像的宽度和高度的示例亚马逊链接:

http://images.amazon.com/images/P/0099441365.01.SCLZZZZZZZ.jpg

我正在使用 jsoup，以下是我的代码:

import java.io.*;
import org.jsoup.*;
import org.jsoup.nodes.Document;
import org.jsoup.select.Elements;
public class Crawler_main {

/**
 * @param args
 */
public static void main(String[] args) {
    // TODO Auto-generated method stub
    String filepath = "C:/imagelinks.txt";
    try (BufferedReader br = new BufferedReader(new FileReader(filepath))) {
        String line;
        String width;
        //String height;
        while ((line = br.readLine()) != null) {
           // process the line.
            System.out.println(line);
            Document doc = Jsoup.connect(line).ignoreContentType(true).get();
            //System.out.println(doc.toString());
            Elements jpg = doc.getElementsByTag("img");
            width = jpg.attr("width");
            System.out.println(width);
            //String title = doc.title();
        }
    }
    catch (FileNotFoundException ex){
        System.out.println("File not found");
    }
    catch(IOException ex){
        System.out.println("Unable to read line");
    }
    catch (Exception ex){
        System.out.println("Exception occured");
    }
}

}

已获取 html，但当我提取宽度属性时，它返回 null。当我打印获取的html时，它包含垃圾字符(我猜测它是我称之为垃圾字符的实际图像信息。例如:

我什至无法将 document.toString() 结果粘贴到此编辑器中。救命!

Answer 1

问题是您正在获取 jpg 文件，而不是任何 HTML。对ignoreContentType(true)的调用提供了一条线索，因为它的documentation状态:

Ignore the document's Content-Type when parsing the response. By default this is false, an unrecognised content-type will cause an IOException to be thrown. (This is to prevent producing garbage by attempting to parse a JPEG binary image, for example.)

如果想获取实际jpg文件的宽度，this SO answer可能有用:

BufferedImage bimg = ImageIO.read(new File(filename));
int width          = bimg.getWidth();
int height         = bimg.getHeight();