在我的生产管道中,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’已清理’的XHTML和uri传递给渲染器.
比我将’已清理’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解决它们.
我成功使用以下代码缓存图像.如何缓存.css文件呢？我想避免将所有文件放入我的类路径中.
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;
}
}
解决方法
在这里遇到同样问题的人是我如何解决它.
由于我无法在我的CustomUserAgent中缓存* .css文件,我必须找到另一种方法.我的解决方案使用 Squid作为http-proxy来缓存所有常用资源.
由于我无法在我的CustomUserAgent中缓存* .css文件,我必须找到另一种方法.我的解决方案使用 Squid作为http-proxy来缓存所有常用资源.
在我的CustomUserAgent中,我只需要通过传递proxy-object来访问此代理.
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,缓存和未缓存资源之间的差异很大
