JSP
Employment/Purpose
Basically there are two approaches to use ZK in JSP pages.
- Use
<jsp:include>to include a ZUL page. - Use ZK JSP Tags in a JSP page directly.
Here we discuss the general concepts applicable to both approaches. For information of ZK JSP Tags, please refer to ZK JSP Tags Essentials. It is also worth to take a look at the HTML Tags section.
Prerequisite
DOCTYPE
To use ZK components correctly, the JSP page must specify DOCTYPE as follows.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
...
BODY Style
By default, ZK will set the CSS style of the BODY tag to width:100%;height:100% If you prefer to have the browser to decide the height (i.e., the browser's default) for you, you could specify height:auto to the BODY tag (optional).
<body style="height:auto">
...
Browser Cache
Though optional, it is suggested to disable the browser to cache the result page. It can be done as follows.
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Pragma" content="no-cache" />
<meta http-equiv="Expires" content="-1" />
In addition, you could invoke the following statement in JSP to tell ZK to drop desktops once the user navigates to other URL. It is optional but it saves memory since the browser page is not cached and safe to remove if the user navigates away.
<%
request.setAttribute(org.zkoss.zk.ui.sys.Attributes.NO_CACHE, Boolean.TRUE);
%>
Notice that it has to be invoked before ZK JSP's zkhead tag, if ZK JSP is used, or before the first jsp:include that includes a ZUL page.
HTML Form
ZK input components (datebox, slider, listbox and so on) work seamlessly with HTML form. In addition to Ajax, you could process input in batch with Servlets.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<%@ taglib uri="http://www.zkoss.org/jsp/zul" prefix="z" %>
<html>
<body>
<z:page>
<form action="/foo/legacy">
<table>
<tr>
<td>When</td><td><z:datebox name="when"/></td>
</tr>
<tr>
<td>Which></td>
<td>
<z:listbox name="which">
<z:listitem label="choice 1"/>
<z:listitem label="choice 2"/>
</z:listbox>
</td>
</tr>
<tr>
<td><z:button type="submit" label="Submit"/></td>
<td><z:button type="reset" label="Reset"/></td>
</tr>
</form>
</z:page>
</body>
</html>
The name Property
If you want to submit the values of the ZK components, you have to place the component inside the form and then specify the name property. Thus, when the form is submitted, the value of, say, the datebox will be sent together with the name you specified. For example,
<window title="Submit" border="normal" xmlns:n="native">
<n:form action="/fooLegacy">
<grid>
<rows>
<row>
When
<datebox name="when" />
Name
<textbox name="name" />
</row>
<row>
Department
<combobox name="department">
<comboitem label="RD" />
<comboitem label="Manufactory" />
<comboitem label="Logistics" />
</combobox>
Type
<listbox name="type">
<listitem label="New" value="new"/>
<listitem label="Average" value="avarage"/>
</listbox>
</row>
<row>
<button type="submit" label="Submit"/>
</row>
</rows>
</grid>
</n:form>
</window>
Once users press the submit button, a request is posted to the /fooLegacy servlet with the query string as follows.
?when=Nov+10%2C+2010&name=Mark+Gates&department=Manufactory&type=new
Thus, as long as you maintain the proper associations between name and value, your servlet could work as usual without any modification.
Components that Support the name Property
All input-types components support the name property, such as textbox, datebox, decimalbox, intbox, combobox,bandbox, slider and calendar.
In addition, the list boxes and tree controls also support the name property. If the multiple property is true and users select multiple items, then multiple name/value pairs are posted.
<listbox name="who" multiple="true" width="200px">
<listhead>
<listheader label="name"/>
<listheader label="gender"/>
</listhead>
<listitem value="mary">
<listcell label="Mary"/>
<listcell label="FEMALE"/>
</listitem>
<listitem value="john">
<listcell label="John"/>
<listcell label="MALE"/>
</listitem>
<listitem value="jane">
<listcell label="Jane"/>
<listcell label="FEMALE"/>
</listitem>
<listitem value="henry">
<listcell label="Henry"/>
<listcell label="MALE"/>
</listitem>
</listbox>
If both John and Henry are selected, then the query string will contain:
who=john&who=henry
Notice that, to use the list boxes and tree controls with the name property, you have to specify the value property for listitem and treeitem, respectively. They are the values being posted to the servlets.
Rich User Interfaces
Because a form component could contain any kind of components, the rich user interfaces could be implemented independently of the existent servlets. For example, you could listen to the onOpen event and fulfill a tab panel as illustrated in the previous sections. Yet another example, you could dynamically add more rows to a grid control, where each row might control input boxes with the name property. Once user submits the form, the most updated content will be posted to the servlet.
Communication with zul
Pass Data to zul
Query String
If the data you pass can be visible to users, you can just pass it through a query string.
Just put a hyperlink on a page: <a href="mypage.zul?myparam=myvalue"/>
or
call HttpServletResponse.sendRedirect(req.getContextPath() + "/redirected.zul?myparam=myvalue") in a Servlet.
In ZK, you get the passed data with Executions.getCurrent().getParameter("mykey")
Session Attributes
HttpServletRequest.getSession().setAttribute("myKey", "myValue")
Pass Data to JSP
Query String
Just put a hyperlink on a page: <a href="mypage.zul?myparam=myvalue"/>
or
call Executions.getCurrent().sendRedirect("/redirected.zul?myparam=myvalue") in a ZK Controller.
Session Attributes
Sessions.getCurrent().setAttribute("myKey", "myValue")