纯JSP+DWR实现三级联动下拉选择菜单实现技巧
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2023-11-20 21:06:22
网上看到一些例子，对于一个简单的三级联动，都加上什么struts, hibernate诸如此类的框架。这个ajax联动殊不知和这些框架有什么关系，一个小demo干嘛整得那么...
网上看到一些例子，对于一个简单的三级联动，都加上什么struts, hibernate诸如此类的框架。这个ajax联动殊不知和这些框架有什么关系，一个小demo干嘛整得那么大。
今天我做了一个dwr+jsp做的例子。
web.xml:
<?xml version="1.0" encoding="utf-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"
xsi:schemalocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<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>
</servlet>
<servlet>
<servlet-name>selectservlet</servlet-name>
<servlet-class>com.action.selectservlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectservlet</servlet-name>
<url-pattern>/select</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
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>
<!-- 没有它dwr什么也做不了 -->
<allow>
<create creator="new" javascript="menu">
<param name="class" value="com.dao.countrydao" />
</create>
<!-- 要转换的bean -->
<convert converter="bean" match="com.vo.country" />
<convert converter="bean" match="com.vo.province" />
<convert converter="bean" match="com.vo.city" />
</allow>
</dwr>
test.jsp:
<%@ page language="java" import="java.util.*,com.vo.*"
pageencoding="gbk"%>
<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c"%>
<html>
<head>
<title>dwr三级联动</title>
<script type='text/javascript'
src='/mutiplymenu/dwr/interface/menu.js'></script>
<script type='text/javascript' src='/mutiplymenu/dwr/engine.js'></script>
<script type='text/javascript' src='/mutiplymenu/dwr/util.js'></script>
</head>
<body>
<script type="text/javascript">
//根据国家id查询所属省或州
function queryprovince()
{
var countryid = $("country").value;
//默认为不选择
if(countryid == 0)
{
${"province"}.options.length=0;
${"city"}.options.length=0;
}
else
{
menu.queryprovincebyid(countryid,provincecallback);
}
}
//根据国家id查询所属省或州的回调函数
function provincecallback(provinces)
{
${"province"}.options.length=0;
//每次获得新的数据的时候先把每二个下拉框架的长度清0
for(var i=0;i< provinces.length;i ++){
var value = provinces[i].id;
var text = provinces[i].provincename;
var option = new option(text, value);
//根据每组value和text标记的值创建一个option对象
try{
$("province").add(option);//将option对象添加到第二个下拉框中
}catch(e){
}
}
//同时关联第三级
var provinceid = ${"province"}.value;
menu.querycitybyid(provinceid,citycallback);
}
//查询所属城市
function querycity()
{
var provinceid = $("province").value;
menu.querycitybyid(provinceid,citycallback);
}
//查询所属城市回调函数
function citycallback(citys)
{
//每次获得新的数据的时候先把每三个下拉框架的长度清0
${"city"}.options.length=0;
for(var i=0;i< citys.length;i ++){
var value = citys[i].id;
var text = citys[i].cityname;
var option = new option(text, value);
//根据每组value和text标记的值创建一个option对象
try{
$("city").add(option);//将option对象添加到第三个下拉框中
}catch(e){
}
}
}
function change1()
{
queryprovince();
}
function change2()
{
querycity();
}
</script>
<div align="center">
<h3>
<br>
</h3>
<h3>
dwr三级联动演示
</h3>
<!-- 我都奇怪了，我的<c>标签在这里不能用 -->
<select id="country" onchange="change1();">
<option selected="selected" value="0">
请选择
</option>
<%
@suppresswarnings("unchecked")
list list = (list) request.getattribute("countrys");
for (int i = 0; i < list.size(); i++)
{
country temp = (country) list.get(i);
%>
<option value="<%=temp.getid()%>"><%=temp.getcountryname()%></option>
<%
}
%>
</select>
<select id="province" onchange="change2();">
</select>
<select id="city">
</select>
</div>
</body>
</html>
servlet,dao就不帖了，想了解的可以去下载源码
今天我做了一个dwr+jsp做的例子。
web.xml:
复制代码 代码如下:
<?xml version="1.0" encoding="utf-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"
xsi:schemalocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<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>
</servlet>
<servlet>
<servlet-name>selectservlet</servlet-name>
<servlet-class>com.action.selectservlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectservlet</servlet-name>
<url-pattern>/select</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
dwr.xml:
复制代码 代码如下:
<?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>
<!-- 没有它dwr什么也做不了 -->
<allow>
<create creator="new" javascript="menu">
<param name="class" value="com.dao.countrydao" />
</create>
<!-- 要转换的bean -->
<convert converter="bean" match="com.vo.country" />
<convert converter="bean" match="com.vo.province" />
<convert converter="bean" match="com.vo.city" />
</allow>
</dwr>
test.jsp:
复制代码 代码如下:
<%@ page language="java" import="java.util.*,com.vo.*"
pageencoding="gbk"%>
<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c"%>
<html>
<head>
<title>dwr三级联动</title>
<script type='text/javascript'
src='/mutiplymenu/dwr/interface/menu.js'></script>
<script type='text/javascript' src='/mutiplymenu/dwr/engine.js'></script>
<script type='text/javascript' src='/mutiplymenu/dwr/util.js'></script>
</head>
<body>
<script type="text/javascript">
//根据国家id查询所属省或州
function queryprovince()
{
var countryid = $("country").value;
//默认为不选择
if(countryid == 0)
{
${"province"}.options.length=0;
${"city"}.options.length=0;
}
else
{
menu.queryprovincebyid(countryid,provincecallback);
}
}
//根据国家id查询所属省或州的回调函数
function provincecallback(provinces)
{
${"province"}.options.length=0;
//每次获得新的数据的时候先把每二个下拉框架的长度清0
for(var i=0;i< provinces.length;i ++){
var value = provinces[i].id;
var text = provinces[i].provincename;
var option = new option(text, value);
//根据每组value和text标记的值创建一个option对象
try{
$("province").add(option);//将option对象添加到第二个下拉框中
}catch(e){
}
}
//同时关联第三级
var provinceid = ${"province"}.value;
menu.querycitybyid(provinceid,citycallback);
}
//查询所属城市
function querycity()
{
var provinceid = $("province").value;
menu.querycitybyid(provinceid,citycallback);
}
//查询所属城市回调函数
function citycallback(citys)
{
//每次获得新的数据的时候先把每三个下拉框架的长度清0
${"city"}.options.length=0;
for(var i=0;i< citys.length;i ++){
var value = citys[i].id;
var text = citys[i].cityname;
var option = new option(text, value);
//根据每组value和text标记的值创建一个option对象
try{
$("city").add(option);//将option对象添加到第三个下拉框中
}catch(e){
}
}
}
function change1()
{
queryprovince();
}
function change2()
{
querycity();
}
</script>
<div align="center">
<h3>
<br>
</h3>
<h3>
dwr三级联动演示
</h3>
<!-- 我都奇怪了，我的<c>标签在这里不能用 -->
<select id="country" onchange="change1();">
<option selected="selected" value="0">
请选择
</option>
<%
@suppresswarnings("unchecked")
list list = (list) request.getattribute("countrys");
for (int i = 0; i < list.size(); i++)
{
country temp = (country) list.get(i);
%>
<option value="<%=temp.getid()%>"><%=temp.getcountryname()%></option>
<%
}
%>
</select>
<select id="province" onchange="change2();">
</select>
<select id="city">
</select>
</div>
</body>
</html>
servlet,dao就不帖了，想了解的可以去下载源码