ImageIO.read() 返回 403 错误

问题描述

我有以下代码:

public BufferedImage urlToImage(String imageUrl) throws MalformedURLException, IOException {
    URL url = new URL(imageUrl);
    BufferedImage image = ImageIO.read(url);
    return image;
}

这应该从给定的 URL 返回图像.

That is supposed to return an image from a given URL.

我用这两个随机选择的 URL 进行了测试:

I tested with these two randomly chosen URLs:

• https://www.google.co.ma/images/srpr/logo4w.png
• http://www.earthtimes.org/newsimage/osteoderms-storing-minerals-helped-huge-dinosaurs-survive_3011.jpg

第一个工作正常，但第二个给出了 403 错误:

The first one works fine, but the second gives a 403 error:

Caused by: java.io.IOException: Server returned HTTP response code: 403 for URL: http://www.earthtimes.org/newsimage/osteoderms-storing-minerals-helped-huge-dinosaurs-survive_3011.jpg
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1436)
at java.net.URL.openStream(URL.java:1010)
at javax.imageio.ImageIO.read(ImageIO.java:1367)

错误的原因可能是什么?谢谢.

What could be the cause of the error ? Thanks.

推荐答案

ImageIO.read(URL) 方法使用几乎所有默认设置打开 URL 连接，包括 User-Agent 属性(将设置为您正在运行的 JVM 版本).显然，您列出的站点需要更标准"的 UA.使用直接 telnet 连接进行测试:

The ImageIO.read(URL) method opens a URL connection with pretty much all default settings, including the User-Agent property (which will be set to the JVM version you are running on). Apparently, the site you listed expects a more 'standard' UA. Testing with a straight telnet connection:

ImageIO.read(url)发送的请求:

GET/newsimage/osteoderms-storing-minerals-helped-huge-dinosaurs-survive_3011.jpg HTTP/1.1
用户代理:Java/1.7.0_17
主持人:www.earthtimes.org
接受:文本/html、图像/gif、图像/jpeg、*；q=.2, /;q=.2
连接:保持连接

响应代码是 404(至少对我而言)，返回一个默认的 text/html 页面.

标准"浏览器发送的请求:

Request sent by 'standard' browser:

GET/newsimage/osteoderms-storing-minerals-helped-huge-dinosaurs-survive_3011.jpg HTTP/1.1
用户代理:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.65 Safari/537.31
主持人:www.earthtimes.org
接受:文本/html、图像/gif、图像/jpeg、*；q=.2, /;q=.2
连接:保持连接

响应代码是 200，带有图像数据.

以下简单的修复延长了您的代码，但通过设置更标准"的 UA 解决了问题:

The following simple fix lengthens your code, but gets around the problem, by setting a more 'standard' UA:

final String urlStr = "http://www.earthtimes.org/newsimage/osteoderms-storing-minerals-helped-huge-dinosaurs-survive_3011.jpg";
final URL url = new URL(urlStr);
final HttpURLConnection connection = (HttpURLConnection) url
        .openConnection();
connection.setRequestProperty(
    "User-Agent",
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.65 Safari/537.31");
final BufferedImage image = ImageIO.read(connection.getInputStream());

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