数据URI - 如何在Java中创建它们？ [英] Data URI - how to create them in Java?
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问题描述
我刚被告知使用数据URI发送图像的缩略图。我一直在搜索它，但我发现它基本上是文件的文本表示，可以直接在HTML中使用。我无法真正找到如何在Java中创建数据URI。我有一个文件的输入流。有人可以对此有所了解并指出我的方法来产生这个吗？
I have just been told to send the thumbnail of an image using data URI. I have been searching it but all I found was that its basically a textual representation of a file and can be directly used in HTML. I could not really find how to make a data URI in Java. I have an input stream of a file. Can someone please shed some light on it and point me to a way to generate this?
推荐答案
E.G。对于图像：
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
ImageIO.write(image, "png", baos);
} catch (IOException e) {
e.printStackTrace();
}
String imageString = "data:image/png;base64," +
DatatypeConverter.printBase64Binary(baos.toByteArray());
示例
运行以下代码。如果FF是默认浏览器，您可能会看到如下内容：
Example
Run the code below. If FF is the default browser, you might see something like this:
import java.awt.*;
import java.awt.image.BufferedImage;
import javax.xml.bind.DatatypeConverter;
import javax.imageio.ImageIO;
import java.io.ByteArrayOutputStream;
import java.io.*;
public class DataUriConverter {
public static void main(String[] args) throws Exception {
int sz = 200;
BufferedImage image = new BufferedImage(
sz, sz, BufferedImage.TYPE_INT_ARGB);
// paint the image..
Graphics2D g = image.createGraphics();
g.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g.setColor(Color.BLUE);
for (int ii = 0; ii < sz; ii += 5) {
g.drawOval(ii, ii, sz - ii, sz - ii);
}
g.dispose();
// convert the image
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(image, "png", baos);
System.out.println("baos.toByteArray() " + baos.toByteArray());
System.out.println("baos.toByteArray().length " + baos.toByteArray().length);
String data = DatatypeConverter.printBase64Binary(baos.toByteArray());
String imageString = "data:image/png;base64," + data;
String html =
"<html><body><img src='" + imageString + "'></body></html>";
// write the HTML
File f = new File("image.html");
FileWriter fw = new FileWriter(f);
fw.write(html);
fw.flush();
fw.close();
// display the HTML
Desktop.getDesktop().open(f);
}
}
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