java - 从 URL 获取图像 (Java)

Question

我正在尝试阅读以下图片

但它显示 IIOException。

这是代码：

Image image = null;
URL url = new URL("http://bks6.books.google.ca/books?id=5VTBuvfZDyoC&printsec=frontcover&img=1& zoom=5&edge=curl&source=gbs_api");
image = ImageIO.read(url);
jXImageView1.setImage(image); 

Answer 1

这段代码对我来说很好。

 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URL;

public class SaveImageFromUrl {

public static void main(String[] args) throws Exception {
    String imageUrl = "http://www.avajava.com/images/avajavalogo.jpg";
    String destinationFile = "image.jpg";

    saveImage(imageUrl, destinationFile);
}

public static void saveImage(String imageUrl, String destinationFile) throws IOException {
    URL url = new URL(imageUrl);
    InputStream is = url.openStream();
    OutputStream os = new FileOutputStream(destinationFile);

    byte[] b = new byte[2048];
    int length;

    while ((length = is.read(b)) != -1) {
        os.write(b, 0, length);
    }

    is.close();
    os.close();
}

}

Answer 2

您收到HTTP 400（错误请求）错误，因为space您的 URL 中有一个。如果你修复它（在zoom参数之前），你会得到一个HTTP 401错误（未经授权）。也许您需要一些 HTTP 标头来将您的下载标识为可识别的浏览器（使用“User-Agent”标头）或其他身份验证参数。

对于 User-Agent 示例，然后使用ImageIO.read(InputStream)使用连接输入流：

URLConnection connection = url.openConnection();
connection.setRequestProperty("User-Agent", "xxxxxx");

使用任何需要的东西xxxxxx

Answer 3

试试这个：

//urlPath = address of your picture on internet
URL url = new URL("urlPath");
BufferedImage c = ImageIO.read(url);
ImageIcon image = new ImageIcon(c);
jXImageView1.setImage(image);

Answer 4

直接调用 URL 获取图像可能会涉及重大安全问题。您需要确保您有足够的权限来访问该资源。但是，您可以使用ByteOutputStream读取图像文件。这是一个示例（它只是一个示例，您需要根据您的要求进行必要的更改。）

ByteArrayOutputStream bis = new ByteArrayOutputStream();
InputStream is = null;
try {
  is = url.openStream ();
  byte[] bytebuff = new byte[4096]; 
  int n;

  while ( (n = is.read(bytebuff)) > 0 ) {
    bis.write(bytebuff, 0, n);
  }
}

Answer 5

尝试：

public class ImageComponent extends JComponent {
  private final BufferedImage img;

  public ImageComponent(URL url) throws IOException {
    img = ImageIO.read(url);
    setPreferredSize(new Dimension(img.getWidth(), img.getHeight()));

  }

  @Override
  protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    g.drawImage(img, 0, 0, img.getWidth(), img.getHeight(), this);
  }

  public static void main(String[] args) throws Exception {
    final URL kitten = new URL("https://placekitten.com/g/200/300");

    final ImageComponent image = new ImageComponent(kitten);

    JFrame frame = new JFrame("Test");
    frame.add(new JScrollPane(image));

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 300);
    frame.setVisible(true);
  }
}

Answer 6

您可以尝试使用此类来显示从 JFrame 中的 URL 读取的图像。

public class ShowImageFromURL {

    public static void show(String urlLocation) {
        Image image = null;
        try {
            URL url = new URL(urlLocation);
            URLConnection conn = url.openConnection();
            conn.setRequestProperty("User-Agent", "Mozilla/5.0");

            conn.connect();
            InputStream urlStream = conn.getInputStream();
            image = ImageIO.read(urlStream);

            JFrame frame = new JFrame();
            JLabel lblimage = new JLabel(new ImageIcon(image));
            frame.getContentPane().add(lblimage, BorderLayout.CENTER);
            frame.setSize(image.getWidth(null) + 50, image.getHeight(null) + 50);
            frame.setVisible(true);

        } catch (IOException e) {
            System.out.println("Something went wrong, sorry:" + e.toString());
            e.printStackTrace();
        }
    }
}

参考：https ://gist.github.com/aslamanver/92af3ac67406cfd116b7e4e177156926