download files from server and compress it in zip format [duplicate]

Question

im trying to implement a download all functionality, my requirement is file should be compressed in .zip, heres the UI

<p:toolbar>
    <f:facet name="right">
         <p:commandButton value="Download all photos" ajax="false" actionListener="#{ManageActivities.getAllParticipantPhoto}" onclick="PrimeFaces.monitorDownload(start, stop);" icon="ui-icon-image">
            <p:fileDownload value="#{ManageActivities.file}" /> 
      </p:commandButton>
  </f:facet></p:toolbar>

and here is the managedbean code

private StreamedContent file;

public void getAllParticipantPhoto() {   
    ByteArrayInputStream bis = new ByteArrayInputStream(zipBytes());
    InputStream stream = bis;
    file = new DefaultStreamedContent(stream, "zip", "photos.zip"); 

}

private byte[] zipBytes () {   
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    ZipOutputStream zos = new ZipOutputStream(baos);

    try{
        for(Participants p : partcpnts){
            if(p.getPhoto() != null){
                ZipEntry entry = new ZipEntry(p.getFirstName()+".jpg");
                zos.putNextEntry(entry);
                zos.write(p.getPhoto());
               }                
            }
    }catch(Exception e){
        e.printStackTrace();
    }

    return baos.toByteArray();
}

i can download file as ZIP successfully but i am unable to extract it, windows is prompting the'cannot open file as archive' error

Answer 1

changing

file = new DefaultStreamedContent(stream, "zip", "photos.zip"); 

to

file = new DefaultStreamedContent(stream, "application/zip", "photos.zip",  Charsets.UTF_8.name());

fixed it