DWR实现级联

来源：互联网发布：数据可视化原理编辑：程序博客网时间：2024/05/17 08:06

DWR实现级联

关键字: ajax-dwr

dwr2.0 web.xml配置：

<servlet>
<servlet-name>dwr-invoker</servlet-name>
<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
<init-param >
<param-name>classes</param-name>
<param-value>java.lang.Object</param-value>
</init-param>
<load-on-startup>100</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>

操作类
public class DwrTest
{
@SuppressWarnings("unchecked")
public Map getClassList() {
Map map = new LinkedHashMap();
map.put("0", "请选择");
map.put("1", "班级一");
map.put("2", "班级二");
map.put("3", "班级三");
return map;
}

@SuppressWarnings("unchecked")
public Map getUserList(String id) {
Map map = new LinkedHashMap();
if(id.equals("1")) {
map.put("1", "同学一");
map.put("2", "同学二");
map.put("3", "同学三");
} else if(id.equals("2")) {
map.put("4", "同学四");
map.put("5", "同学五");
map.put("6", "同学六");
} else if(id.equals("3")) {
map.put("7", "同学七");
map.put("8", "同学八");
map.put("9", "同学九");
} else {
map.put("", "请选择");
}
return map;
}
}

在与web.xml同目录下建一个dwr.xml：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://www.getahead.ltd.uk/dwr/dwr20.dtd">
<dwr>
<allow>
<create creator="new" javascript="opt">
<param name="class" value="cn.ffcs.hr.pm.base.test.DwrTest"></param>
</create>
</allow>

</dwr>

页面：

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ page language="java" pageEncoding="UTF-8"%>
<html>
<head>
<title>dwrTest</title>

<script type='text/javascript' src='<c:url value="/dwr/engine.js"/>'></script>
<script type='text/javascript' src='<c:url value="/dwr/util.js"/>'></script>
<script type='text/javascript' src='<c:url value="/dwr/interface/opt.js"/>'></script>

<script type="text/javascript">
//获得班级列表
function updateClass() {
opt.getClassList(createClass);
}
function createClass(data) {
DWRUtil.removeAllOptions("classid");
DWRUtil.addOptions("classid", data);
}
//获得人员列表
function updateUser() {
opt.getUserList(DWRUtil.getValue("classid"),createUser);
}
function createUser(data) {
DWRUtil.removeAllOptions("userid");
DWRUtil.addOptions("userid", data);
}

</script>
</head>

<body onload="updateClass()">
<br/><br/>

<table align="center" width="200" border="1">
<tr>
<td>
Class:
<select name="classid" id="classid" onchange="javascript:updateUser();">
</select>
</td>

<td>
User:<select name="userid" id="userid"></select>
</td>
</tr>
</table>

</body>