<zk>
	<window apply="org.zkoss.bind.BindComposer"
		viewModel="@id('vm') @init('foo.FiledownloadVM')">
		<textbox value="@bind(vm.dynamicContent)"/>
		
		<button  label="download" onClick="@command('download')" />
	</window>
</zk>

import org.zkoss.bind.annotation.Command;
import org.zkoss.cht.system.DownloadFilter;
import org.zkoss.util.media.AMedia;
import org.zkoss.zk.ui.Executions;
import org.zkoss.zk.ui.util.Clients;

public class FiledownloadVM {

	private String dynamicContent = "downloadContent";
	
	
	@Command
	public void download() {
		InputStream is = new ByteArrayInputStream(dynamicContent.getBytes(Charset.forName("utf-8")));
		
		AMedia media = new AMedia("file", "txt", "text/plain", is);
		
		String url = Executions.getCurrent().getDesktop().getDownloadMediaURI(media, "report");
		Clients.evalJavaScript("window.open('"+url+"')");
	}


	public String getDynamicContent() {
		return dynamicContent;
	}
	
	public void setDynamicContent(String dynamicContent) {
		this.dynamicContent = dynamicContent;
	}

}