Struts logic标签

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<logic:present>：判断数据是否存在

<logic:notPresent>：判断数据是否不存在

标签属性：

cookie，header，name，parameter，user，property，scope

<body>    <%request.setAttribute("name", "xiaoming");%>    <logic:present name="name" scope="request">                     存在    </logic:present>    <logic:notPresent name="name" scope="request">                     不存在    </logic:notPresent>    </body>

<logic:empty>：判断数据是否为空

<logic:notEmpty>：判断数据是否不为空

<body>    <%        List<String> list = new ArrayList<String>();        request.setAttribute("list", list);    %>    <jsp:useBean id="testbean" class="com.bean.TestBean" scope="request"></jsp:useBean>      <jsp:setProperty name="testbean" property="name"  value="xiaot"></jsp:setProperty>      <logic:empty name="list" scope="request">          list为空    </logic:empty>    <logic:notEmpty name="testbean" property="name" scope="request">         TestBean中的name不为null    </logic:notEmpty>    </body>

关系运算标签：

<logic:equal>：判断是否相等

<logic:notEqual>：是否不等

<logic:greaterEqual>：是否大于等于

<logic:lessEqual>：是否小于等于

<logic:lessThan>：是否小于

<logic:greaterThan>：是否大于

<logic:iterate>

提供迭代输出功能

<body>    <%        String arr[] = {"element1","element2","element3"};   request.setAttribute("arr", arr);            List<String> list = new ArrayList<String>();        list.add("a");        list.add("b");        list.add("c");        request.setAttribute("list", list);                Map<String, String> map = new HashMap<String, String>();        map.put("map1","map1");        map.put("map2","map2");        map.put("map3","map3");        request.setAttribute("map", map);    %>    <h3>输出数组</h3>    <logic:iterate id="id" name="arr" scope="request">       <li>数组：${id}</li>    </logic:iterate>    <h3>输出集合</h3>    <logic:iterate id="id1" name="list" scope="request">        <li>集合：${id1}</li>    </logic:iterate>    <h3>输出map</h3>    <logic:iterate id="id2" name="map" scope="request">        <li>map：${id2.key}--${id2.value}</li>    </logic:iterate></body>

页面输出：

输出数组
数组：element1
数组：element2
数组：element3

输出集合
集合：a
集合：b
集合：c

输出map
map：map3--map3
map：map2--map2
map：map1--map1

<logic:redirect>

页面重定向操作

struts-config中注册：

    <global-forwards>        <forward name="success" path="/jsp/success.jsp"></forward>    </global-forwards>

JSP：

<body> <logic:redirect forward="success" /></body>