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要在JSP中使用Struts 2.0标志，先要指明标志的引入。通过在JSP的代码的顶部加入以下代码可以做到这点。
<%@taglib prefix="s" uri="/struts-tags" %>
非UI标志
if、elseif和else
描述：
执行基本的条件流转。

参数：

名称必需默认类型描述备注
test 是 Boolean 决定标志里内容是否显示的表达式 else标志没有这个参数
id 否 Object/String 用来标识元素的id。在UI和表单中为HTML的id属性
例子：

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>Condition Flow</title>
    </head>
    <body>
        <h3>Condition Flow</h3>
        
        <s:set name="name" value="<%= "'" + request.getParameter("name") + "'" %>" />
        <s:if test="#name == 'Max'">
            Max's file here
        </s:if>
        <s:elseif test="#name == 'Scott'">
            Scott's file here
        </s:elseif>
        <s:else>
            Other's file here
        </s:else>
    </body>
</html>
例1 condition.jsp
iterator
描述：
用于遍历集合（java.util.Collection）或枚举值（java.util.Iterator）。

参数：

名称必需默认类型描述
status 否 String 如果设置此参数，一个IteratorStatus的实例将会压入每个遍历的堆栈
value 否 Object/String 要遍历的可枚举的（iteratable）数据源，或者将放入新列表（List）的对象
id 否 Object/String 用来标识元素的id。在UI和表单中为HTML的id属性
例子：

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ page import="java.util.List" %>
<%@ page import="java.util.ArrayList" %>
<%@ taglib prefix="s" uri="/struts-tags" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<%
    List list = new ArrayList();
    list.add("Max");
    list.add("Scott");
    list.add("Jeffry");
    list.add("Joe");
    list.add("Kelvin");
    request.setAttribute("names", list);
%>
<html>
    <head>
        <title>Iterator</title>
    </head>
    <body>
        <h3>Names: </h3>
        
        <ol>
            <s:iterator value="#request.names" status="stuts">
                <s:if test="#stuts.odd == true">
                    <li>White <s:property /></li>
                </s:if>
                <s:else>
                    <li style="background-color:gray"><s:property /></li>
                </s:else>
            </s:iterator>
        </ol>
    </body>
</html>
例2 iterator.jsp
i18n
描述：
加载资源包到值堆栈。它可以允许text标志访问任何资源包的信息，而不只当前action相关联的资源包。

参数：

名称必需默认类型描述
value 是 Object/String 资源包的类路径（如com.xxxx.resources.AppMsg）
id 否 Object/String 用来标识元素的id。在UI和表单中为HTML的id属性
例子：

HelloWorld=Hello Wrold!
例3 classes\ ApplicationMessages.properties

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>Internationization</title>
    </head>
    <body>
        <h3>
            <s:i18n name="ApplicationMessages">
                <s:text name="HelloWorld" />
            </s:i18n>
        </h3>
    </body>
</html>
例3 i18n.jsp
include
描述：
包含一个servlet的输出（servlet或jsp的页面）。

参数：

名称必需默认类型描述
value 是 String 要包含的jsp或servlet
id 否 Object/String 用来标识元素的id。在UI和表单中为HTML的id属性
例子：

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>Iterator</title>
    </head>
    <body>
        <h3>Interator Page</h3>
        <s:include value="/condition.jsp">
            <s:param name="name">Max</s:param>
        </s:include>
        <h3>i18n</h3>
        <s:include value="/i18n.jsp" />
    </body>
</html>
例4 include.jsp
param
描述：
为其他标签提供参数,比如include标签和bean标签. 参数的name属性是可选的,如果提供，会调用Component的方法addParameter(String, Object), 如果不提供，则外层嵌套标签必须实现UnnamedParametric接口(如TextTag)。

value的提供有两种方式,通过value属性或者标签中间的text,不同之处我们看一下例子:
<param name="color">blue</param>
<param name="color" value="blue"/>
(A)参数值会以String的格式放入statck.
(B)该值会以java.lang.Object的格式放入statck.
参数：

名称必需默认类型描述
name 否 String 参数名
value 否 String value表达式
id 否 Object/String 用来标识元素的id。在UI和表单中为HTML的id属性
例子：
请参考例4。

set
描述：
set标签赋予变量一个特定范围内的值。当希望给一个变量赋一个复杂的表达式,每次访问该变量而不是复杂的表达式时用到。其在两种情况下非常有用: 复杂的表达式很耗时 (性能提升) 或者很难理解 (代码可读性提高)。

参数：

名称必需默认类型描述
name 是 String 变量名字
scope 否 String 变量作用域,可以为application, session, request, page, 或action.
value 否 Object/String 将会赋给变量的值
id 否 Object/String 用来标识元素的id。在UI和表单中为HTML的id属性
例子：
请参考例1。

text
描述：
支持国际化信息的标签。国际化信息必须放在一个和当前action同名的resource bundle中,如果没有找到相应message,tag body将被当作默认message,如果没有tag body,message的name会被作为默认message。

参数：

名称必需默认类型描述
name 是 String 资源属性的名字
id 否 Object/String 用来标识元素的id。在UI和表单中为HTML的id属性
例子：
请参考例3。

url
描述：
该标签用于创建url,可以通过"param"标签提供request参数。

当includeParams的值时'all'或者'get', param标签中定义的参数将有优先权,也就是说其会覆盖其他同名参数的值。
参数：略

例子：

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>URL</title>
    </head>
    <body>
        <h3>URL</h3>
        <a href='<s:url value="/i18n.jsp" />'>i18n</a><br />
        <s:url id="url" value="/condition.jsp">
            <s:param name="name">Max</s:param>
        </s:url>
        <s:a href="%{url}">if\elseif\else</s:a>
    </body>
</html>
例5 url.jsp
property
描述：
得到'value'的属性,如果value没提供,默认为堆栈顶端的元素。

参数：

名称必需默认类型描述
default 否 String 如果属性是null则显示的default值
escape 否 true Booelean 是否escape HTML
value 否栈顶 Object 要显示的值
id 否 Object/String 用来标识元素的id。在UI和表单中为HTML的id属性
例子：
请参考例2。

UI标志
UI标志又可以分为表单UI和非表单UI两部分。表单UI部分基本与Struts 1.x相同，都是对HTML表单元素的包装。不过，Struts 2.0加了几个我们经常在项目中用到的控件如：datepicker、doubleselect、timepicker、optiontransferselect等。因为这些标志很多都经常用到，而且参数也很多，要在一篇文章详细说明并非易事。

需要深入了解这些标志的朋友，可以到以下查看以下网址：
http://wiki.javascud.org/display/ww2cndoc/Tags WebWork2文档中文化计划（中文）
http://cwiki.apache.org/WW/tag-reference.html Tag Developers Guide（英文）
本文有相当的内容也来自这两处。
在此，我虽然不能够详细讲述这些标志，但是可以与大家分享一个来Struts 2.0 Show Case一个例子。

/*
* $Id: UITagExample.java 420385 2006-07-10 00:57:05Z mrdon $
*
* Copyright 2006 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.struts2.showcase;

import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.Validateable;
import com.opensymphony.xwork2.util.OgnlValueStack;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.io.File;

/**
*/
public class UITagExample extends ActionSupport implements Validateable {

    private static final long serialVersionUID = -94044809860988047L;
    String name;
    Date birthday;
    String bio;
    String favoriteColor;
    List friends;
    boolean legalAge;
    String state;
    String region;
    File picture;
    String pictureContentType;
    String pictureFileName;
    String favouriteLanguage;
    String favouriteVehicalType = "MotorcycleKey";
    String favouriteVehicalSpecific = "YamahaKey";

    List leftSideCartoonCharacters;
    List rightSideCartoonCharacters;

    List favouriteLanguages = new ArrayList();
    List vehicalTypeList = new ArrayList();
    Map vehicalSpecificMap = new HashMap();

    String thoughts;

    public UITagExample() {
        favouriteLanguages.add(new Language("EnglishKey", "English Language"));
        favouriteLanguages.add(new Language("FrenchKey", "French Language"));
        favouriteLanguages.add(new Language("SpanishKey", "Spanish Language"));

        VehicalType car = new VehicalType("CarKey", "Car");
        VehicalType motorcycle = new VehicalType("MotorcycleKey", "Motorcycle");
        vehicalTypeList.add(car);
        vehicalTypeList.add(motorcycle);

        List cars = new ArrayList();
        cars.add(new VehicalSpecific("MercedesKey", "Mercedes"));
        cars.add(new VehicalSpecific("HondaKey", "Honda"));
        cars.add(new VehicalSpecific("FordKey", "Ford"));

        List motorcycles = new ArrayList();
        motorcycles.add(new VehicalSpecific("SuzukiKey", "Suzuki"));
        motorcycles.add(new VehicalSpecific("YamahaKey", "Yamaha"));

        vehicalSpecificMap.put(car, cars);
        vehicalSpecificMap.put(motorcycle, motorcycles);
    }

    public List getLeftSideCartoonCharacters() {
        return leftSideCartoonCharacters;
    }
    public void setLeftSideCartoonCharacters(List leftSideCartoonCharacters) {
        this.leftSideCartoonCharacters = leftSideCartoonCharacters;
    }

    public List getRightSideCartoonCharacters() {
        return rightSideCartoonCharacters;
    }
    public void setRightSideCartoonCharacters(List rightSideCartoonCharacters) {
        this.rightSideCartoonCharacters = rightSideCartoonCharacters;
    }

    public String getFavouriteVehicalType() {
        return favouriteVehicalType;
    }

    public void setFavouriteVehicalType(String favouriteVehicalType) {
        this.favouriteVehicalType = favouriteVehicalType;
    }

    public String getFavouriteVehicalSpecific() {
        return favouriteVehicalSpecific;
    }

    public void setFavouriteVehicalSpecific(String favouriteVehicalSpecific) {
        this.favouriteVehicalSpecific = favouriteVehicalSpecific;
    }

    public List getVehicalTypeList() {
        return vehicalTypeList;
    }

    public List getVehicalSpecificList() {
        OgnlValueStack stack = ServletActionContext.getValueStack(ServletActionContext.getRequest());
        Object vehicalType = stack.findValue("top");
        if (vehicalType != null && vehicalType instanceof VehicalType) {
            List l = (List) vehicalSpecificMap.get(vehicalType);
            return l;
        }
        return Collections.EMPTY_LIST;
    }

    public List getFavouriteLanguages() {
        return favouriteLanguages;
    }

    public String execute() throws Exception {
        return SUCCESS;
    }

    /* Getters and Setters */

    public String doSubmit() {
        return SUCCESS;
    }

    // === inner class
    public static class Language {
        String description;
        String key;

        public Language(String key, String description) {
            this.key = key;
            this.description = description;
        }

        public String getKey() {
            return key;
        }
        public String getDescription() {
            return description;
        }

    }

    public static class VehicalType {
        String key;
        String description;
        public VehicalType(String key, String description) {
            this.key = key;
            this.description = description;
        }

        public String getKey() { return this.key; }
        public String getDescription() { return this.description; }

        public boolean equals(Object obj) {
            if (! (obj instanceof VehicalType)) {
                return false;
            }
            else {
                return key.equals(((VehicalType)obj).getKey());
            }
        }

        public int hashCode() {
            return key.hashCode();
        }
    }

    public static class VehicalSpecific {
        String key;
        String description;
        public VehicalSpecific(String key, String description) {
            this.key = key;
            this.description = description;
        }

        public String getKey() { return this.key; }
        public String getDescription() { return this.description; }

        public boolean equals(Object obj) {
            if (! (obj instanceof VehicalSpecific)) {
                return false;
            }
            else {
                return key.equals(((VehicalSpecific)obj).getKey());
            }
        }

        public int hashCode() {
            return key.hashCode();
        }
    }
}
例6 org.apache.struts2.showcase.UITagExample.java

<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
    <title>UI Tags Example</title>
    <s:head/>
</head>
<body>

<s:actionerror/>
<s:actionmessage/>
<s:fielderror />

<s:form action="exampleSubmit" method="post" enctype="multipart/form-data" tooltipConfig="#{'jsTooltipEnabled':'true'}">
    <s:textfield
            label="Name"
            name="name"
            tooltip="Enter your Name here" />

    <s:datepicker
            tooltip="Select Your Birthday"
            label="Birthday"
            name="birthday" />

    <s:textarea
            tooltip="Enter your Biography"
            label="Biograph"
            name="bio"
            cols="20"
            rows="3"/>

    <s:select
            tooltip="Choose Your Favourite Color"
            label="Favorite Color"
            list="{'Red', 'Blue', 'Green'}"
            name="favoriteColor"
            emptyOption="true"
            headerKey="None"
            headerValue="None"/>

    <s:select
            tooltip="Choose Your Favourite Language"
            label="Favourite Language"
            list="favouriteLanguages"
            name="favouriteLanguage"
            listKey="key"
            listValue="description"
            emptyOption="true"
            headerKey="None"
            headerValue="None"/>

    <s:checkboxlist
            tooltip="Choose your Friends"
            label="Friends"
            list="{'Patrick', 'Jason', 'Jay', 'Toby', 'Rene'}"
            name="friends"/>

    <s:checkbox
            tooltip="Confirmed that your are Over 18"
            label="Age 18+"
            name="legalAge"/>

    <s:doubleselect
            tooltip="Choose Your State"
            label="State"
            name="region" list="{'North', 'South'}"
            value="'South'"
            doubleValue="'Florida'"
            doubleList="top == 'North' ? {'Oregon', 'Washington'} : {'Texas', 'Florida'}"
            doubleName="state"
            headerKey="-1"
            headerValue="---------- Please Select ----------"
            emptyOption="true" />

    <s:doubleselect
            tooltip="Choose your Vehical"
            label="Favourite Vehical"
            name="favouriteVehicalType"
            list="vehicalTypeList"
            listKey="key"
            listValue="description"
            value="'MotorcycleKey'"
            doubleValue="'YamahaKey'"
            doubleList="vehicalSpecificList"
            doubleListKey="key"
            doubleListValue="description"
            doubleName="favouriteVehicalSpecific" headerKey="-1"
            headerValue="---------- Please Select ----------"
            emptyOption="true" />

    <s:file
            tooltip="Upload Your Picture"
            label="Picture"
            name="picture" />

    <s:optiontransferselect
            tooltip="Select Your Favourite Cartoon Characters"
            label="Favourite Cartoons Characters"
            name="leftSideCartoonCharacters"
            leftTitle="Left Title"
            rightTitle="Right Title"
            list="{'Popeye', 'He-Man', 'Spiderman'}"
            multiple="true"
            headerKey="headerKey"
            headerValue="--- Please Select ---"
            emptyOption="true"
            doubleList="{'Superman', 'Mickey Mouse', 'Donald Duck'}"
            doubleName="rightSideCartoonCharacters"
            doubleHeaderKey="doubleHeaderKey"
            doubleHeaderValue="--- Please Select ---"
            doubleEmptyOption="true"
            doubleMultiple="true" />

    <s:textarea
            label="Your Thougths"
            name="thoughts"
            tooltip="Enter your thoughts here" />

    <s:submit onclick="alert('aaaa');" />
    <s:reset onclick="alert('bbbb');" />
</s:form>

</body>
</html>
例6 example.jsp

<action name="example" class="org.apache.struts2.showcase.UITagExample">
    <result>example.jsp</result>
    <result name="input">example.jsp</result>
</action>

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