在java中将图像嵌入到HTML中？

Question

我有这个代码,我试图从Url读取图像:

   public class question_insert {
public static String latex(String tex) throws IOException {

    String urltext = "http://chart.apis.google.com/chart?cht=tx&chl="+tex;

    URL url = new URL(urltext);
    BufferedReader in = new BufferedReader(new InputStreamReader(url
            .openStream()));
    String inputLine;

    while ((inputLine = in.readLine()) != null) {
        // Process each line.
        System.out.println(inputLine.toString());

    }
    in.close();

    return inputLine;}

但我得到的是无法读取的代码.网址只提供一张图片试试这个:

http://chart.apis.google.com/chart?cht=tx&chl=2+2%20\frac{3}{4}

我该怎么做才能将图像嵌入到Html中？

Answer 1

首先,不清楚Html格式的图像是什么意思？您可以对Base64编码其二进制数据,但这是您真正想要的吗？

您希望如何将URL返回的PNG图片输出到文本控制台(即System.out)？

其次,即使你将它作为PNG文件存储在磁盘上,你检索图像的方式也不起作用,因为Reader及其衍生产品如BufferedReader用于读取字符数据.来自Reader API:

用于读取字符流的抽象类

您需要读取二进制(字节)数据,因此您需要坚持使用BufferedInputStream

经过一番思考后,我意识到将图像嵌入到HTML中是你真正想要的:

public static void main(String[] args) throws Exception {
    String urltext = "http://chart.apis.google.com/chart?cht=tx&chl=2+2%20\\frac{3}{4}";
    URL url = new URL(urltext);
    BufferedInputStream bis = new BufferedInputStream(url.openStream());
    byte[] imageBytes = new byte[0];
    for(byte[] ba = new byte[bis.available()];
        bis.read(ba) != -1;) {
        byte[] baTmp = new byte[imageBytes.length + ba.length];
        System.arraycopy(imageBytes, 0, baTmp, 0, imageBytes.length);
        System.arraycopy(ba, 0, baTmp, imageBytes.length, ba.length);
        imageBytes = baTmp;
    }
    System.out.println("<img src='data:image/png;base64," + DatatypeConverter.printBase64Binary(imageBytes) + "'>");
}

结果是:

<img src='data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABsAAAAhCAIAAACnV0fJAAAABmJLR0QA/wD/AP+gvaeTAAAC/klEQVRIiaWWv0vzQBjHr2ltsGDEyf+giAg5iIO4iiJC8cciQhaLk9IOGpcOii5ugj/qZoeWgqtFXJxrBSnUQTAianTJEJBcjeRCwr3D+caY1ijpd7rnc8lzz/PkuYdECCEgrDDGlmXF43GWZV0YC+0un8/f3993dXU9PT0JgpDL5T43SChdXV0JgnB5eUkIqVarPM+XSiW6xYQLkGEYlmVfXl4AAENDQwCAer3eUYyEENM06aJSqUAIq9UqNcN7JIQYhlGr1RYWFg4ODlwYMmuqer3++vra3d0ty7JlWZ1m7UrX9eHh4XQ67Y8RY9xsNh3H8QXSll9fX5fLZbrmOK6vr+/m5sYwDOD24+HhoaqqmqYpijI1NZXJZIL5xsaGqqqpVIrjOJpoJBL5ynpvb+/8/JzGTD/c/v5+ACeEZLPZ7e1tur67u+N5PpfLUTNimmYqlZqZmVleXqZnTExM2LZdqVTm5uZa+cXFRTQatSxra2vLMAyGYWRZhhBubm7G43EAANB1HUIIIdR1nR6STqd5nn9+fm7LXZMQYpomQshtTKoYx3Hr6+u0wDQWTdMSiUR/f39b7h0KLMt6zfbd8/j4KAhCNpv9I29VhHyfZouLi6qqnp6efhalHW82m/64/iuRSHybZsViESF0dHTkc+flCKGxsbGfPEqS9JX12dnZ0tISxtiXRStHP8u2beCWKZPJuK/t7Oy8v78H8AABQoiiKJIkaZpGz3l7exNFMYD/8mVs2xZFUZZlbzmSyWS5XG7LT05OWsuHMXbbKAYAmJ2d9T2RTCYDuE/FYrHRaOzu7n7av2YRLEVRRkdHvX3a0cQFABQKBd+16chjPp8fGRmJxb41dXiPDw8PCKHJyUkfD+nRcZzj4+O1tbXWrZAeS6XS9PS077JS+SfFX2QYxvz8/MDAADVrtVpvb+/g4KAoihDCkN3jvcvj4+MrKyv0UhNCQv5J9fT0eM1oNOqSjrqn0Wisrq7qun57eytJEsYYhKujK8dxPj4+XJOG+Q+Ygl+7nqaLKQAAAABJRU5ErkJggg=='>

那不是很好吗？什么都适合你!

Answer 2

好吧,我不知道这是不是你想要的,因为似乎没有人这样做.但是如果你想得到这个输出

<img style="-webkit-user-select: none" 
src="http://chart.apis.google.com/chart?cht=tx&chl=2+2%20\frac{3}{4}" />

你将不得不使用这个代码

public static String latex(String tex) {
    String url = "http://chart.apis.google.com/chart?cht=tx&chl=" + tex;
    return "<img style=\"-webkit-user-select: none\" src=\"" + url + "\"/>";
}

此外,您可能必须转义参数\中的某些字符tex.