Struts2 <s:doubleselect>示例

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在Struts2,<s:doubleselect>标签用于创建两个HTML下拉框,第一个下拉列表中…

在Struts2,<s:doubleselect>标签用于创建两个HTML下拉框,第一个下拉列表中选择后,第二个下拉列表将根据第一个选择发生相应的变化。一个非常典型的例子是“国家”,“国家”下拉选项,不同的“状态”列表是根据所选择的“国家”。

这里创建一个Web工程:strut2sdoubleselect,来演示在多个复选框如何设置的默认值,整个项目的结构如下图所示:

Struts2 <s:doubleselect>示例

 <s:doubleselect> 标签示例

<s:doubleselect label="Fruits (OGNL) "   name="fruit1" list="{'fruit','meat'}"   doubleName="fruit2"   doubleList="top == 'fruit' ? {'apple', 'orange','banana'} : {'chicken', 'pig'}" />

产生下面的HTML代码…

<tr>   <td class="tdLabel">    <label for="resultAction_fruit1" class="label">       Fruits (OGNL) :    </label>  </td>   <td>   <select name="fruit1" id="resultAction_fruit1"       onchange="resultAction_fruit1Redirect(this.options.selectedIndex)">       <option value="fruit">fruit</option>       <option value="meat">meat</option>   </select>   <br />   <select name="fruit2" id="resultAction_fruit2">   </select>   <script type="text/javascript">       var resultAction_fruit1Group = new Array(2 + 0);      for (i = 0; i < (2 + 0); i++)      resultAction_fruit1Group[i] = new Array();         resultAction_fruit1Group[0][0] = new Option("apple", "apple");         resultAction_fruit1Group[0][1] = new Option("orange", "orange");         resultAction_fruit1Group[0][2] = new Option("banana", "banana");         resultAction_fruit1Group[1][0] = new Option("chicken", "chicken");         resultAction_fruit1Group[1][1] = new Option("pig", "pig");            var resultAction_fruit1Temp = document.resultAction.resultAction_fruit2;      resultAction_fruit1Redirect(0);      function resultAction_fruit1Redirect(x) {      	var selected = false;          for (m = resultAction_fruit1Temp.options.length - 1; m >= 0; m--) {              resultAction_fruit1Temp.options[m] = null;          }             for (i = 0; i < resultAction_fruit1Group[x].length; i++) {              resultAction_fruit1Temp.options[i] =   	     new Option(                resultAction_fruit1Group[x][i].text, resultAction_fruit1Group[x][i].value               );           }             if ((resultAction_fruit1Temp.options.length > 0) && (! selected)) {             	resultAction_fruit1Temp.options[0].selected = true;          }      }  </script>     </td>   </tr>

好了,<s:doubleselect>标签是真正产生大量的代码。它会创建两个下拉列表, 很多JavaScript代码背后做魔术(第一选择,第二个变化),并且还附上了“onchange()”行为,以第一个下拉框。

看起来比较复杂,但简单!
这只是两个<s:select>标记结合在一个标签,看得很清楚了。

<s:doubleselect  name="" list=""   doubleName="" doubleList="" />

name”和“list”是指第一个下拉列表。“doubleName”和“doubleList”是指所述第二下拉列表。数据群和“”标签是一样的。 

Struts2 <s:doubleselect> 示例

在一个完整的例子,例如<S:doubleselect>标签,表示使用OGNL或Java列出数据来填充到下拉列表中。

1. Action

Action类来生成两个下拉列表。
DoubleSelectAction.java

package com.yiibai.common.action;    import java.util.ArrayList;  import java.util.Arrays;  import java.util.HashMap;  import java.util.Map;  import java.util.Set;    import com.opensymphony.xwork2.ActionSupport;    public class DoubleSelectAction extends ActionSupport{    	private String fruit1;  	private String fruit2;  	  	private String server1;  	private String server2;  	  	private String language1;  	private String language2;  	  	Map languageMap;    	public String getFruit1() {  		return fruit1;  	}    	public void setFruit1(String fruit1) {  		this.fruit1 = fruit1;  	}    	public String getFruit2() {  		return fruit2;  	}    	public void setFruit2(String fruit2) {  		this.fruit2 = fruit2;  	}    	public String getServer1() {  		return server1;  	}    	public void setServer1(String server1) {  		this.server1 = server1;  	}    	public String getServer2() {  		return server2;  	}    	public void setServer2(String server2) {  		this.server2 = server2;  	}    	public String getLanguage1() {  		return language1;  	}    	public void setLanguage1(String language1) {  		this.language1 = language1;  	}    	public String getLanguage2() {  		return language2;  	}    	public void setLanguage2(String language2) {  		this.language2 = language2;  	}    	public Map getLanguageMap() {  		return languageMap;  	}    	public void setLanguageMap(Map languageMap) {  		this.languageMap = languageMap;  	}    	public DoubleSelectAction(){  	  languageMap =new HashMap();		  		            languageMap.put("Java",               new ArrayList<String>(Arrays.asList("Spring", "Hibernate", "Struts 2")));            languageMap.put(".Net", new ArrayList<String>(Arrays.asList("VB.Net", "C#")));            languageMap.put("JavaScript", new ArrayList<String>(Arrays.asList("jQuery")));  	}    	public String execute() {  		return SUCCESS;  	}  	  	public String display() {  		return NONE;  	}  	  }

2. 结果页面

渲染两个下拉下拉框,通过“<s:doubleselect>”标签,并通过Java列表,OGNL列表填充

doubleselect.jsp

<%@ taglib prefix="s" uri="/struts-tags" %>  <html>  <head>  </head>    <body>  <h1>Struts2 <s:doubleselect> 示例</h1>    <s:form action="resultAction" namespace="/">    <s:doubleselect label="Fruits (OGNL) "   name="fruit1" list="{'fruit','meat'}"   doubleName="fruit2"   doubleList="top == 'fruit' ? {'apple', 'orange','banana'} : {'chicken', 'pig'}" />    <s:set name="serverList"        value="#{           'AppServer': {'Apache', 'Tomcat', 'JBoss'},           'Database': {'Oracle', 'MySQL'}           }" />  <s:doubleselect label="Server (OGNL) "   name="server1" list="#serverList.keySet()"   doubleName="server2" doubleList="#serverList[top]" />    <s:doubleselect label="Language (Java List) "   name="language1" list="languageMap.keySet()"   doubleName="language2" doubleList="languageMap.get(top)" />    <s:submit value="submit" name="submit" />  	  </s:form>    </body>  </html>

result.jsp

<%@ taglib prefix="s" uri="/struts-tags" %>  <html>    <body>  <h1>Struts2 <s:doubleselect> 示例</h1>    <h2>    Test #1 : <s:property value="fruit1"/> , <s:property value="fruit2"/>  </h2>     <h2>    Test #2 : <s:property value="server1"/> , <s:property value="server2"/>  </h2>     <h2>    Test #2 : <s:property value="language1"/> , <s:property value="language2"/>  </h2>     </body>  </html>

3. struts.xml

<?xml version="1.0" encoding="UTF-8" ?>  <!DOCTYPE struts PUBLIC  "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"  "http://struts.apache.org/dtds/struts-2.0.dtd">     <struts>     <constant name="struts.devMode" value="true" />   	  <package name="default" namespace="/" extends="struts-default">  		     <action name="doubleSelectAction"            class="com.yiibai.common.action.DoubleSelectAction" method="display">  	<result name="none">/pages/doubleselect.jsp</result>     </action>  		     <action name="resultAction" class="com.yiibai.common.action.DoubleSelectAction">  	<result name="success">/pages/result.jsp</result>     </action>    </package>  	  </struts>

5. 示例

http://localhost:8080/strut2sdoubleselect/doubleSelectAction.action

Struts2 <s:doubleselect>示例

http://localhost:8080/strut2sdoubleselect/resultAction.action

Struts2 <s:doubleselect>示例

参考

代码下载:

  

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