在我的生产流程中,我需要从 HTML 生成几百个 PDF。对于这种情况,我首先将 HTML 转换为 XHTML。 比我将“清理过的”XHTML 和 uri 传递给渲染器。
由于 *.css 和 imageFiles 对于所有 XHTML 文件都是相同的,所以我不需要在处理文件时一直解析它们。 我成功地使用以下代码缓存图像。我如何缓存 .css 文件?我想避免将所有文件都放入我的类路径中。
ITextRenderer renderer = new ITextRenderer();
ResourceLoaderUserAgent callback = new ResourceLoaderUserAgent(renderer.getOutputDevice());
callback.setSharedContext(renderer.getSharedContext());
for (MyObject myObject : myObjectList) {
OutputStream os = new FileOutputStream(tempFile);
final DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
documentBuilderFactory.setValidating(false);
DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();
org.w3c.dom.Document document = builder.parse(myObject.getLocalPath); // full path to .xhtml
renderer.getSharedContext().setUserAgentCallback(callback);
renderer.setDocument(document, myObject.getUri());
renderer.layout();
renderer.createPDF(os);
os.flush();
os.close();
}
...
private static class ResourceLoaderUserAgent extends ITextUserAgent
{
public ResourceLoaderUserAgent(ITextOutputDevice outputDevice) {
super(outputDevice);
}
protected InputStream resolveAndOpenStream(String uri) {
InputStream is = super.resolveAndOpenStream(uri);
System.out.println("IN resolveAndOpenStream() " + uri);
return is;
}
}
最佳答案
如果有人在这里遇到同样的问题,我就是这样解决的。 由于我无法在我的 CustomUserAgent 中缓存 *.css 文件,我不得不寻找另一种方法。我的解决方案使用 Squid作为 http 代理来缓存所有常用资源。
在我的 CustomUserAgent 中,我只需要通过传递代理对象来访问这个代理。
public class ResourceLoaderUserAgent extends ITextUserAgent {
public ResourceLoaderUserAgent(ITextOutputDevice outputDevice) {
super(outputDevice);
}
protected InputStream resolveAndOpenStream(String uri) {
HttpURLConnection connection = null;
URL proxyUrl = null;
try {
Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("localhost", 3128));
proxyUrl = new URL(uri);
connection = (HttpURLConnection) proxyUrl.openConnection(proxy);
connection.connect();
} catch (Exception e) {
throw new RuntimeException(e);
}
java.io.InputStream is = null;
try {
is = connection.getInputStream();
} catch (java.net.MalformedURLException e) {
XRLog.exception("bad URL given: " + uri, e);
} catch (java.io.FileNotFoundException e) {
XRLog.exception("item at URI " + uri + " not found");
} catch (java.io.IOException e) {
XRLog.exception("IO problem for " + uri, e);
}
return is;
}
}
缓存:
resolving css took 74 ms
resolving images took 225 ms
未缓存:
resolving css took 15466 ms
resolving images took 11236 ms
如您所见,缓存资源和未缓存资源之间的差异非常显着
关于java - XHTML 到 PDF 使用 Flying Saucer 如何缓存 css,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/11633236/