Revision as of 08:57, 30 July 2013

Overview

In this section, we will demonstrate how to make DOM elements interact with Spreadsheet in a JSP by AJAX request. We suppose you know some basics about JQuery.

The example application is a simple page to request for leave. A user fills the required field in cells and click "OK" button to submit his request for leave. Or he can clicks "Reset" button to reset what he inputs to default value. The screenshot below shows a request of a user "John":

Interaction between JSP and Spreadsheet

The sequence diagram displays the overall handling process of a AJAX request when a user clicks a button in leave.jsp.

The leave.jsp is the page that contains spreadsheet. The ForLeaveServlet is a servlet we implement for the application to handle AJAX requests from leave.jsp. JsonUpdateBridge is a utility class that provides access to ZK desktop and starts an execution in foreign AJAX channel. We should access components like spreadsheet in its process() method and it will generate corresponding AU response for us.

Firstly, leave.jsp sends AJAX request with required parameter such as desktop ID, spreadsheet UUID, and application related data to ForLeaveServlet. The servlet extracts necessary parameters to create JsonUpdateBridge object and call its process() handle AJAX request. Then response the JSON object which contains ZK AU response to the client. Then we use a Javascript utility object zssjsp provided by Spreadsheet to process ZK AU response and write some codes to process other data of the JSON response according to our business logic.

Using Spreadsheet Tag

<%@page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@taglib prefix="zssjsp" uri="http://www.zkoss.org/jsp/zss"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
		<title>Application for Leave</title>
		<zssjsp:head/>
	</head>
<body>
	<button id="resetBtn">Reset</button>
	<button id="checkBtn">OK</button>
	<div>
		<zssjsp:spreadsheet id="myzss" 
			bookProvider="org.zkoss.zss.jspdemo.DemoBookProvider"
			width="800px" height="600px" 
			maxrows="100" maxcolumns="20"
			showToolbar="true" showFormulabar="true" showContextMenu="true" showSheetbar="true"/>
	</div>
	...
</body>

Book Provider

public class DemoBookProvider implements BookProvider{

	public Book loadBook(ServletContext servletContext, HttpServletRequest request, HttpServletResponse res) {
		
		Book book;
		try {
			URL bookUrl = servletContext.getResource("/WEB-INF/books/application_for_leave.xlsx");
			book = Importers.getImporter().imports(bookUrl, "app4leave");
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}

		//initialize the book model
		...
	}
}

Send AJAX Request

<body>
	<button id="resetBtn">Reset</button>
	<button id="checkBtn">OK</button>
	<div>
		<zssjsp:spreadsheet id="myzss" 
			bookProvider="org.zkoss.zss.jspdemo.DemoBookProvider"
			width="800px" height="600px" 
			maxrows="100" maxcolumns="20"
			showToolbar="true" showFormulabar="true" showContextMenu="true" showSheetbar="true"/>
	</div>
	<script type="text/javascript">
	//jq is jquery name in zk, which version is 1.6.4 in sparedsheet 3.0.0 (zk 6.5.3 and later) 
	jq(document).ready(function(){
		//register client event on button by jquery api 
		jq("#checkBtn").click(function(){
			postAjax("check");
		});
		jq("#resetBtn").click(function(){
			postAjax("reset");
		});
	});
	
	function postAjax(action){
		//get the necessary zk ids form zssjsp[component_id] 
		//'myzss' is the sparedhseet id that you gaved in sparedsheet tag 
		var desktopId = zssjsp['myzss'].desktopId; 
		var zssUuid = zssjsp['myzss'].uuid;
		
		
		//use jquery api to post ajax to your servlet (in this demo, it is AjaxBookServlet),
		//provide desktop id and spreadsheet uuid to access zk component data in your servlet 
		jq.ajax({url:"app4l",//the servlet url to handle ajax request 
			data:{desktopId:desktopId,zssUuid:zssUuid,action:action},
			type:'POST',dataType:'json'}).done(handleAjaxResult);
	}
...

zssjsp

Handle AJAX Request and Response

public class ForLeaveServlet extends HttpServlet{

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		//set encoding
		req.setCharacterEncoding("UTF-8");
		resp.setCharacterEncoding("UTF-8");
		//json content type
		resp.setContentType("application/json");
		
		//parameter from ajax request, you have to pass it in AJAX request
		//necessary parameter to get ZK server side desktop
		final String desktopId = req.getParameter("desktopId");
		//necessary parameter to get ZK server side spreadsheet
		final String zssUuid = req.getParameter("zssUuid");
		
		final String action = req.getParameter("action");
		
		// prepare a json result object, it can contain your ajax result and
		// also the necessary zk component update result
		final JSONObject result = new JSONObject();
		// set back for client to check action result, it depends on your logic.
		result.put("action", action);
		
		// use utility class to wrap zk in servlet request and
		// get access and response result
		JsonUpdateBridge bridge = new JsonUpdateBridge(getServletContext(), req, resp,
				desktopId) {
			@Override
			protected void process(Desktop desktop) {
				Spreadsheet ss = (Spreadsheet)desktop.getComponentByUuidIfAny(zssUuid);
				Book book = ss.getBook();
				Sheet sheet = book.getSheetAt(0);
				
				if("reset".equals(action)){
					handleReset(sheet,result);
				}else if("check".equals(action)){
					handleCheck(sheet,result);
				}
			}
		};
		
		/*
		 * Generate ZK update result in given JSON object. An AJAX response
		 * handler at client side, zssjsp, will 'eval' this result to update ZK
		 * components.
		 */
		bridge.process(result);

		Writer w = resp.getWriter();
		w.append(result.toJSONString());	
	}
...
}

Reset Cells

public class ForLeaveServlet extends HttpServlet{
...
	//reset cells to default value
	private void handleReset(Sheet sheet, JSONObject result) {
		final String dateFormat =  "yyyy/MM/dd";
		//you can use a cell reference to get a range
		Range from = Ranges.range(sheet,"E5");//Ranges.range(sheet,"From");
		//or you can use a name to get a range (the named range has to be set in Excel);
		from.setCellEditText(DateUtil.tomorrow(0,dateFormat));
		
		//set other cells...
	}

Check Cells

public class ForLeaveServlet extends HttpServlet{
...
	//validate cell data of user input and return a JSONObject
	private void handleCheck(Sheet sheet, JSONObject result) {
		Date from = Ranges.rangeByName(sheet,"From").getCellData().getDateValue();
		Date to = Ranges.rangeByName(sheet,"To").getCellData().getDateValue();
		String reason = Ranges.rangeByName(sheet,"Reason").getCellData().getStringValue();
		Double total = Ranges.rangeByName(sheet,"Total").getCellData().getDoubleValue();
		String applicant = Ranges.rangeByName(sheet,"Applicant").getCellData().getStringValue();
		Date requestDate = Ranges.rangeByName(sheet,"RequestDate").getCellData().getDateValue();
		
		if(from == null){
			result.put("message", "FROM is empty");
		}else if(to == null){
			result.put("message", "TO is empty");
		}else if(total==null || total.intValue()<0){
			result.put("message", "TOTAL small than 1");
		}else if(reason == null){
			result.put("message", "REASON is empty");
		}else if(applicant == null){
			result.put("message", "APPLICANT is empty");
		}else if(requestDate == null){
			result.put("message", "REQUEST DATE is empty");
		}else{
			//Option 1:
			//You can handle your business logic here and return a final result for user directly
			
			
			
			//Or option 2: return necessary form data, 
			//so client can process it by submitting that can be handled by Spring MVC or Struts
			result.put("valid", true);
			JSONObject form = new JSONObject();
			result.put("form", form);

			form.put("from", from.getTime());//can't pass as data, use long for time
			form.put("to", to.getTime());//can't pass as data, use long for time
			form.put("reason", reason);
			form.put("total", total.intValue());//we just need int
			form.put("applicant", applicant);
			form.put("requestDate", requestDate.getTime());
			
			//You can also store the book, and load it back later by export it to a file
			Exporter exporter = Exporters.getExporter();
			FileOutputStream fos = null;
			try {
				File temp = File.createTempFile("app4leave_", ".xlsx");
				fos = new FileOutputStream(temp); 
				exporter.export(sheet.getBook(), fos);
				System.out.println("file save at "+temp.getAbsolutePath());
				form.put("archive", temp.getName());
			} catch (IOException e) {
				e.printStackTrace();
			} finally{
				if(fos!=null)
					try {
						fos.close();
					} catch (IOException e) {
						//handle the exception
					}
			}
		}
	}
...
}

Process AJAX Response

leave.jsp

	//the method to handle ajax result from your servlet 
	function handleAjaxResult(result){
		//process the json result that contains zk client update information 
		zssjsp.processJson(result);
		
		//use your way to hanlde you ajax message or error 
		if(result.message){
			alert(result.message);
		};
		
		//use your way handle your ajax action result 
		if(result.action == "check" && result.valid){
			if(result.form){
				//create a form dynamically to submit the form data 
				var field,form = jq("<form action='submitted.jsp' method='post'/>").appendTo('body');
				for(var nm in result.form){
					field = jq("<input type='hidden' name='"+nm+"' />").appendTo(form);
					field.val(result.form[nm]);
				}
				form.submit();
			}
		};
	}

@@ Line 19: / Line 19: @@
 In this section, we will demonstrate how to make DOM elements interact with Spreadsheet in a JSP by AJAX request. We suppose you know some basics about [http://jquery.com JQuery].
-The example application is a simple page to request for leave. A user fills the required field in cells and click "OK" button to submit his request for leave. The screenshot below shows a request of a user "John":
+The example application is a simple page to request for leave. A user fills the required field in cells and click "OK" button to submit his request for leave. Or he can clicks "Reset" button to reset what he inputs to default value. The screenshot below shows a request of a user "John":
 [[File:essentials-jsp-app.png | center]]
@@ Line 25: / Line 25: @@
 == Interaction between JSP and Spreadsheet ==
+The sequence diagram displays the overall handling process of a AJAX request when a user clicks a button in leave.jsp.
 [[File:essentials-jsp-interaction.png | center]]
+The leave.jsp is the page that contains spreadsheet. The <tt>ForLeaveServlet</tt> is a servlet we implement for the application to handle AJAX requests from <tt>leave.jsp</tt>. <javadoc>JsonUpdateBridge</javadoc> is a utility class that provides access to ZK desktop and starts an execution in foreign AJAX channel. We should access components like spreadsheet in its <tt>process()</tt> method and it will generate corresponding AU response for us.
+Firstly, <tt>leave.jsp</tt> sends AJAX request with required parameter such as desktop ID, spreadsheet UUID, and application related data to <tt>ForLeaveServlet</tt>. The servlet extracts necessary parameters to create <tt>JsonUpdateBridge</tt> object and call its <tt>process()</tt> handle AJAX request. Then response the JSON object which contains ZK AU response to the client. Then we use a Javascript utility object <tt>zssjsp</tt> provided by Spreadsheet to process ZK AU response and write some codes to process other data of the JSON response according to our business logic.
 = Using Spreadsheet Tag =

Anonymous

Using Spreadsheet JSP Tag"

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