struts2-21常用标签解说

property标签

property标签用于输出指定值：

<s:set name = "name" value = "yy"/>
<s:property value = "#name"/>

default : 可选属性，如果需要输出的属性值为null，则显示该属性指定的值。
escape：可选属性，指定是否格式html代码。
value：可选属性，指定需要输出的属性值，如果没有指定该属性，则默认输出ValueStack栈顶的值。
id：可选属性，指定该元素的标识。

iterator标签

iterator标签用于对集合进行迭代，这里的集合包含List、Set和数组。

<s:set name = "list" value = "{'zhangsan','xiaohong','xiaozhang'}"/>
<s:iterator value = "#list" status = "st">
    <font color = <s:if test = "#st.odd">red</s:if><s:else>blue</s:else>>
    <s:property /></font><br >
</s:iterator>

value :可选属性，指定被迭代的集合，如果没有设置该属性，则使用ValueStack栈顶的集合。
id：可选属性，指定集合里元素的id（已被标注为过时）。
status：可选属性，该属性指定迭代时的iteratorStatus实例。该实例包含如下几个方法：

int getCount(),返回当前迭代了几个元素。
int getIndex()，返回当前迭代元素的索引。
boolean isEven（），返回当前被迭代元素的索引是否是偶数
boolean isOdd（），返回当前被迭代元素的索引是否是奇数
boolean isFirst（），返回当前被迭代的元素是否是第一个元素。
boolean isLast（），返回当前被迭代元素是否是最后一个元素。

if/elseif/else标签

<s:set name = "age" value = "21"/>
<s:if test = "#age == 23">
23
</s:if>
<s:elseif test == "#age==21">
21
</s:elseif>
<s:else>
其他
</s:else>

url标签

<s:url action = "helloworld_add" namespace = "/test">
<s:param name = "persionid" value = "23" />
</s:url>

生成类型如下路径：
/struts/*test/helloworld_add.action*?personid=23
斜体部分为内容路径。

当标签的属性值作为字符串类型处理时，“%”符号的用途是计算OGNL表达式的值。

<s:set name = "myurl" value = "http://www.foshanshop.net"/>
<s:url value = "#myurl"/><br>
<s:url value = "%{#myurl}"/>

输出结果：
http://www.foshanshop.net

表单标签_checkboxlist复选框

如果集合为list

<s:checkboxlist name = "list" list = "{'java','.net','RoR','php'}" value = "{'java','.net'}"/>

生成如下html代码：

<input type = "checkbox" name ="list" value = "java" checked = "checked" /><lable>java</lable>
<input type = "checkbox" name ="list" value = ".net" checked = "checked" /><lable>.net</lable>
<input type = "checkbox" name ="list" value = "RoR"  /><lable>RoR</lable>
<input type = "checkbox" name ="list" value = "php"  /><lable>php</lable>

如果集合为Map

<s:checkboxlist name = "map" list = "#{1:'瑜伽用品',1:'瑜伽用品1',1:'瑜伽用品2',1:'瑜伽用品3'}" listKey = "key" listValue = "value" value = "{1,2,3}"/>

生成如下代码：

<input type = "checkbox" name = "map" value = "1" checked = "checked"/><lable>瑜伽用品1</lable>
<input type = "checkbox" name = "map" value = "2" checked = "checked"/><lable>瑜伽用品2</lable>
<input type = "checkbox" name = "map" value = "3"/><lable>瑜伽用品3</lable>
<input type = "checkbox" name = "map" value = "4"/><lable>瑜伽用品4</lable>

去掉生成集合时，自动生成的页面标签：
在struts中配置常量：

<!--默认的视图主题-->
<constant name = "struts.ui.theme" value = "simple"/>

去掉自动生成其他标签。

表单标签_radio单单选框

该标签的使用和checkboxlist复选框相同。
如果集合里存放的是javabean（personid和name为Person的属性）

<s:radio name = "beans" list = "#request.persons" listKey = "personid" listValue = "name"/>

生成如下html代码：

<input type = "radio" name = "beans" id = "beans1" value = "1"/><lable for = "map1">one</lable>
<input type = "radio" name = "beans" id = "beans1" value = "2"/><lable for = "map2">two</lable>

如果集合为map

<s:radio name = "map" list = "#{1:'瑜伽用品',1:'瑜伽用品1',1:'瑜伽用品2',1:'瑜伽用品3'}" listKey = "key" listValue = "value" value = "{1,2,3}"/>

生成如下代码：

<input type = "radio" name = "map" value = "1" checked = "checked"/><lable>瑜伽用品1</lable>
<input type = "radio" name = "map" value = "2" checked = "checked"/><lable>瑜伽用品1</lable>
<input type = "radio" name = "map" value = "3" checked = "checked"/><lable>瑜伽用品1</lable>
<input type = "radio" name = "map" value = "4"/><lable>瑜伽用品1</lable>

如果集合为list

<s:radio name = "list" list = "{'java','.net'}" value = "java"/>

生成如下代码：

<input type = "checkbox" name ="list" value = "java" checked = "checked" /><lable>java</lable>
<input type = "checkbox" name ="list" value = ".net"/><lable>.net</lable>

表单标签_select下拉选择框

<s:select name = "list" list = "{'java','.net'}" value = "java"/>

效果：

<select name = "list" id = "list">
    <option value = "java" selected = "selected">java</option>
    <option value = "java">.net</option>
</select>

<s:select name = "beans" list = "#request.persions" listKey = "persionid" listValue = "name"/>

效果：

<select name = "beans" id = "beans">
    <option value = "1">第一个</option>
    <option value = "2">第二个</option>
</select>

<s:select name = "map" list = "#{1:'瑜伽用品1'，2:'瑜伽用品2',3:'瑜伽用品3',4:'瑜伽用品4'}" listKey = "key" listValue = "value" value = "1"/>

效果：

<select name = "map" id = "map">
    <option value = "1" selected = "selected">瑜伽用品</option>
    <option value = "2">瑜伽用品2</option>
    <option value = "3">瑜伽用品3</option>
    <option value = "4">瑜伽用品4</option>
</select>