struts2doubleselect示例

struts2  doubleselect示例

doubleselect算是Struts2中稍微复杂点的表单标签, 尤其官方示例比较简单, 没有太大的实用价值.

 

<s:doubleselect label="doubleselect test2" name="menu" list="#{'fruit':'Nice Fruits', 'other':'Other Dishes'}" doubleName="dishes" doubleList="top == 'fruit' ? {'apple', 'orange'} : {'monkey', 'chicken'}" />

 

从这个官方示例中可以看到基本用法, list开头的代表的是第一级下拉框的属性, doubleList开头的则是第二级下拉框. 与select标签的属性基本是对应的.

 

在实际应用中, 我们比较关注的就是list和doubleList这两个属性了, list是存放的第一级下拉框的数据集合, 比如List<FatherBean>, 而doubleList就可以用Map<String, List<SonBean>>来存储, 其中map的键名String与第一级下拉框相关联.

 

现在来展示一个我写的示例：

先写两个javaBean，一般情况下是跟数据库的表相关联的：

package com.student.bean;

public class Province {  int id;  String name;//set和get方法

}

package com.student.bean;

public class City { int id; String name; int provinceId;//set和get方法}

再来写Action，用来往web页面发送数据：

package com.student.action;

import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import com.opensymphony.xwork2.ActionSupport;import com.student.bean.Province;import com.student.bean.City;

public class DoubleSelectAction extends ActionSupport {    private List<Province> provinceList;    private Map<Integer, List<City>> cityMap;    public List<Province> getProvinceList() {  return provinceList; }

 public void setProvinceList(List<Province> provinceList) {  this.provinceList = provinceList; }

 public Map<Integer, List<City>> getCityMap() {  return cityMap; }

 public void setCityMap(Map<Integer, List<City>> cityMap) {  this.cityMap = cityMap; }

 public String execute() throws Exception {      provinceList= new ArrayList<Province>();

            Province province;            province = new Province();            province.setId(1);            province.setName("山西省");            provinceList.add(province);

            province = new Province();            province.setId(2);            province.setName("陕西省");            provinceList.add(province);

            province = new Province();            province.setId(3);            province.setName("河南省");            provinceList.add(province);

            cityMap = new HashMap<Integer, List<City>>();

            List<City> cityList = new ArrayList<City>();            City city;            city = new City();            city.setId(1);            city.setName("太原市");            city.setProvinceId(1);            cityList.add(city);

            city= new City();            city.setId(2);            city.setName("大同市");            city.setProvinceId(1);            cityList.add(city);                       city= new City();            city.setId(3);            city.setName("长治市");            city.setProvinceId(1);            cityList.add(city);

            cityMap.put(1, cityList);

            cityList = new ArrayList<City>();            city= new City();            city.setId(4);            city.setName("西安市");            city.setProvinceId(2);            cityList.add(city);

            city= new City();            city.setId(5);            city.setName("汉中市");            city.setProvinceId(2);            cityList.add(city);                       city= new City();            city.setId(6);            city.setName("咸阳市");            city.setProvinceId(2);            cityList.add(city);

            cityMap.put(2, cityList);                       cityList = new ArrayList<City>();            city= new City();            city.setId(7);            city.setName("郑州市");            city.setProvinceId(3);            cityList.add(city);

            city= new City();            city.setId(8);            city.setName("开封市");            city.setProvinceId(3);            cityList.add(city);                       city= new City();            city.setId(8);            city.setName("洛阳市");            city.setProvinceId(3);            cityList.add(city);

            cityMap.put(3, cityList);

            return SUCCESS;

 }}

现在写配置文件：

<action name="doubleSelect" class="com.student.action.DoubleSelectAction">           <result name="success">/tagsDoubleSelect.jsp</result></action>

 

最后写显示级联下拉菜单的web页面：

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><!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>struts2级联下拉菜单示例</title> </head> <body>

  <s:form name="f1">   <s:doubleselect list="provinceList" listKey="id" listValue="name"    doubleName="cityId"    doubleList="cityMap.get(top.id)" doubleListKey="id" doubleListValue="name"/>  </s:form> </body></html>

 

此处要注意的是top的用法，top代表的就是list当前选中的对象, 所以top.id对应的就是当前选中的Province对象中的ID, cityMap.get(top.id)即根据当前选中的Province对象中的ID来取出第二级下拉框的数据集合

转自：http://blog.sina.com.cn/s/blog_6145ed810100ebo6.html