I use the following Servlet to map images from a folder of the file-system.
public class ImageServlet extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
// Get the base path for graphics root folder
String basePath = System.getenv(Constants.ENV_VAR);
String specifier = req.getParameter(Constants.PARAMETER);
resp.setContentType(Constants.CONTENT_TYPE);
File file = new File(basePath+specifier+"."+Constants.IMG_TYPE);
resp.setContentLength((int)file.length());
FileInputStream in = new FileInputStream(file);
OutputStream out = resp.getOutputStream();
// Copy the contents of the file to the output stream
byte[] buf = new byte[Constants.INPUT_BUFFER_SIZE];
int count = 0;
while ((count = in.read(buf)) >= 0) {
out.write(buf, 0, count);
}
in.close();
out.close();
}
}
Then, I use GWT-RPC to get images, by using the following AppServiceImpl class:
public class AppServiceImpl extends RemoteServiceServlet implements AppService {
//Get the base path for graphics root folder
String basePath = System.getenv(Constants.ENV_VAR);
@Override
public ArrayList<String> getImageFiles(String folder) {
ArrayList<String> list = new ArrayList<String>();
File parent = new File(**basePath+folder**);
if (!parent.isDirectory()) {
return list;
}
File[] files = parent.listFiles();
for (int i = 0; i < files.length; i++) {
if (files[i].isFile() && !files[i].isHidden()) {
// save image title
list.add(files[i].getName().substring(0, files[i].getName().indexOf(".")));
}
}
return list;
}
...
In order to get an image in GWT code, i use: final Image lgImg = new Image(Constants.URL_PREFIX + imgPath);
where:
URL_PREFIX = "http://localhost:8888/images?" + PARAMETER + "="
ENV_VAR = "APP_GFX_HOME"
PARAMETER = "path"
In development mode, all work good, but when i deploy to a tomcat server, images do not appear, and I need some help to figure out the problem.
p.s: Here is part of web.xml file
<!-- Services -->
<servlet>
<servlet-name>theImageServlet</servlet-name>
<servlet-class>com.app.server.ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>theImageServlet</servlet-name>
<url-pattern>/images</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>appService</servlet-name>
<servlet-class>com.app.server.AppServiceImpl</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>appService</servlet-name>
<url-pattern>/app/services</url-pattern>
</servlet-mapping>
