Based on the example mentioned in - https://gist.github.com/canthony/3655917 I have created a new Vaadin example to upload an Excel/CSV file.
Based on the comments mentioned, I even downloaded opencsv-3.0 from the http://opencsv.sourceforge.net and added them into the project.
Below is how I added them
Right Click on Vaadin project created --> Properties --> Java Build Path --> Add Library (Created new User Library) --> New User Library --> User Libraries --> New (In User Libraries page) --> Created New Library with name CSV --> Included the OpenCSV3.0-jar
Finally this is how my setup looks like:
No errors or warnings are present, but when I publish on tomcat I get below error. This error comes up when I Browse a file and click on Upload button. Can some one please help?
SEVERE:
java.lang.NoClassDefFoundError: au/com/bytecode/opencsv/CSVReader
at com.example.uploadexcel.UploadexcelUI.buildContainerFromCSV(UploadexcelUI.java:101)
at com.example.uploadexcel.UploadexcelUI$2.uploadFinished(UploadexcelUI.java:63)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:508)
at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:198)
at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:161)
at com.vaadin.server.AbstractClientConnector.fireEvent(AbstractClientConnector.java:979)
at com.vaadin.ui.Upload.fireUploadInterrupted(Upload.java:875)
at com.vaadin.ui.Upload$2.streamingFailed(Upload.java:1166)
at com.vaadin.server.communication.FileUploadHandler.streamToReceiver(FileUploadHandler.java:615)
at com.vaadin.server.communication.FileUploadHandler.handleFileUploadValidationAndData(FileUploadHandler.java:447)
at com.vaadin.server.communication.FileUploadHandler.doHandleSimpleMultipartFileUpload(FileUploadHandler.java:397)
at com.vaadin.server.communication.FileUploadHandler.handleRequest(FileUploadHandler.java:282)
at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1402)
at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:305)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
I don't understand why I get java.lang.NoClassDefFoundError when I have added the required jar into the Java build path.
Full code:
public class UploadexcelUI extends UI {
protected File tempFile;
protected Table table;
@WebServlet(value = "/*", asyncSupported = true)
@VaadinServletConfiguration(productionMode = false, ui = UploadexcelUI.class)
public static class Servlet extends VaadinServlet {
}
@SuppressWarnings("deprecation")
@Override
protected void init(VaadinRequest request) {
Upload upload = new Upload("Upload CSV File", new Upload.Receiver() {
@Override
public OutputStream receiveUpload(String filename, String mimeType) {
try {
/* Here, we'll stored the uploaded file as a temporary file. No doubt there's
a way to use a ByteArrayOutputStream, a reader around it, use ProgressListener (and
a progress bar) and a separate reader thread to populate a container *during*
the update.
This is quick and easy example, though.
*/
tempFile = File.createTempFile("temp", ".csv");
return new FileOutputStream(tempFile);
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
});
upload.addListener(new Upload.FinishedListener() {
@Override
public void uploadFinished(Upload.FinishedEvent finishedEvent) {
try {
/* Let's build a container from the CSV File */
FileReader reader = new FileReader(tempFile);
IndexedContainer indexedContainer = buildContainerFromCSV(reader);
reader.close();
tempFile.delete();
/* Finally, let's update the table with the container */
table.setCaption(finishedEvent.getFilename());
table.setContainerDataSource(indexedContainer);
table.setVisible(true);
} catch (IOException e) {
e.printStackTrace();
}
}
});
/* Table to show the contents of the file */
table = new Table();
table.setVisible(false);
/* Main layout */
VerticalLayout layout = new VerticalLayout();
layout.setMargin(true);
layout.setSpacing(true);
layout.addComponent(table);
layout.addComponent(upload);
setContent(layout);
}
/**
* Uses http://opencsv.sourceforge.net/ to read the entire contents of a CSV
* file, and creates an IndexedContainer from it
*
* @param reader
* @return
* @throws IOException
*/
@SuppressWarnings("resource")
protected IndexedContainer buildContainerFromCSV(Reader reader) throws IOException {
IndexedContainer container = new IndexedContainer();
CSVReader csvReader = new CSVReader(reader);
String[] columnHeaders = null;
String[] record;
while ((record = csvReader.readNext()) != null) {
if (columnHeaders == null) {
columnHeaders = record;
addItemProperties(container, columnHeaders);
} else {
addItem(container, columnHeaders, record);
}
}
return container;
}
/**
* Set's up the item property ids for the container. Each is a String (of course,
* you can create whatever data type you like, but I guess you need to parse the whole file
* to work it out)
*
* @param container The container to set
* @param columnHeaders The column headers, i.e. the first row from the CSV file
*/
private static void addItemProperties(IndexedContainer container, String[] columnHeaders) {
for (String propertyName : columnHeaders) {
container.addContainerProperty(propertyName, String.class, null);
}
}
/**
* Adds an item to the given container, assuming each field maps to it's corresponding property id.
* Again, note that I am assuming that the field is a string.
*
* @param container
* @param propertyIds
* @param fields
*/
@SuppressWarnings("unchecked")
private static void addItem(IndexedContainer container, String[] propertyIds, String[] fields) {
if (propertyIds.length != fields.length) {
throw new IllegalArgumentException("Hmmm - Different number of columns to fields in the record");
}
Object itemId = container.addItem();
Item item = container.getItem(itemId);
for (int i = 0; i < fields.length; i++) {
String propertyId = propertyIds[i];
String field = fields[i];
item.getItemProperty(propertyId).setValue(field);
}
}
}
