这有一个解决方案 - 在这里使用 servlet 是一个 servlet,它可以在任何 jsf 应用程序中工作
package com.dossier.web.handlers;
//~--- non-JDK imports --------------------------------------------------------
import com.dossier.backend.services.mongo.FileService;
import com.mongodb.gridfs.GridFSDBFile;
//~--- JDK imports ------------------------------------------------------------
import java.io.*;
import javax.faces.context.FacesContext;
import javax.servlet.ServletException;
import javax.servlet.SingleThreadModel;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.io.IOUtils;
/**
*
* @author Armen Arzumanyan
*/
@WebServlet(urlPatterns = { "/PreviewImage" })
public class PreviewImage extends HttpServlet implements SingleThreadModel {
private static final long serialVersionUID = -6624464650990859671L;
private FileService fileAction = new FileService();
@Override
public void init() throws ServletException {
super.init();
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPreviewImage(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {}
private void doPreviewImage(HttpServletRequest request, HttpServletResponse response) throws IOException {
FacesContext context = FacesContext.getCurrentInstance();
String fileIdStr = request.getParameter("fileId");
String widthStr = request.getParameter("w");
GridFSDBFile file = null;
int width = 0;
if ((widthStr != null) && (widthStr.length() > 0)) {
try {
width = Integer.parseInt(widthStr);
} catch (NumberFormatException e) {}
}
if (fileIdStr != null) {
if (fileAction != null) {
file = fileAction.getFile(fileIdStr.trim());
}
if (file != null) {
byte[] content = IOUtils.toByteArray(file.getInputStream());
if (content != null) {
String mimeType = file.getContentType();
response.addHeader("Pragma", "cache");
response.addHeader("Cache-Control", "max-age=3600, must-revalidate");
response.addDateHeader("Expires", System.currentTimeMillis() + 1000 * 3600 * 10);
response.setContentType(mimeType);
try {
if (((mimeType != null)
&& (mimeType.equalsIgnoreCase("image/gif") || mimeType.equalsIgnoreCase("image/x-png")
|| mimeType.equalsIgnoreCase("image/png") || mimeType.equalsIgnoreCase("image/jpg")
|| mimeType.equalsIgnoreCase("image/jpeg"))) || (width == 0)) {
response.getOutputStream().write(content);
} else {
// ByteArrayInputStream bi = new ByteArrayInputStream(content);
// InputStream thumbStream = scaleImageJPG(bi, width);
// byte[] thumbContent = new byte[thumbStream.available()];
// thumbStream.read(thumbContent);
response.getOutputStream().write(content);
}
} catch (IOException e) {
// log.error("file content send error");
e.printStackTrace();
} catch (Exception e) {
// log.error("file exception: " + e);
e.printStackTrace();
} finally {
content = null;
file = null;
}
return;
}
} else {
// TODO add page not found
response.addHeader("Pragma", "no-cache");
response.addDateHeader("Expires", System.currentTimeMillis() - 1000 * 3600);
try {
response.getWriter().println("file object is null");
} catch (Exception e) {}
return;
}
}
// TODO add page not found
response.addHeader("Pragma", "no-cache");
response.addDateHeader("Expires", System.currentTimeMillis() - 1000 * 3600);
try {
response.getWriter().println("file id is not set");
} catch (Exception e) {}
// log.debug("file ID parameter is not set or file is not found");
return;
}
// </editor-fold>
}
//~ Formatted by Jindent --- http://www.jindent.com
这是一个网页代码
<h:graphicImage id="primage" styleClass="img-rounded img-responsive"
url="/PreviewImage?w=250&fileId=#{updatePersonBean.person.imageId}"
width="250" rendered="#{updatePersonBean.person.imageId != null}"/>
<h:graphicImage id="primagenew" styleClass="img-rounded img-responsive"
url="/resources/img/userpic_simple.gif"
width="250" rendered="#{updatePersonBean.person.imageId == null}"/>
享受