引入
<%@ taglib prefix="sys" tagdir="/WEB-INF/tags/sys" %>
这里注意/WEB-INF/tags/sys这里是一个目录，目录下有很多tag文件如下，调用sys:xxx，就会在当前目录下找xxx.tag的文件，必须有对应xxx.tag的文件与之对应
<%@ tag language="java" pageEncoding="UTF-8"%><%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%><%@ taglib prefix="fns" uri="/WEB-INF/tlds/fns.tld" %><%@ attribute name="typeCode" type="java.lang.String" required="true" description="字典code"%><%@ attribute name="defaultValue" type="java.lang.String" description="默认选中"%><%@ attribute name="style" type="java.lang.String" description="默认选中"%><%@ attribute name="cls" type="java.lang.String" description="默认选中"%><%@ attribute name="name" type="java.lang.String" description="默认选中"%><select style="${style}" class="${cls}" name="${name}" id="${name}" ><option value="" >请选择... </option><c:if test="${not empty typeCode}"><c:forEach items="${fns:getDictList(typeCode)}" var='dict'><option value='${dict.VALUE}' ${defaultValue==dict.VALUE?'selected':''}>${dict.TEXT}</option></c:forEach></c:if></select>attribute的属性介绍如下：
1. name ：这个attribute的名称.
2. required : true/false, 是否必须的.
3. rtexprvalue : true/false, 这个attribute可否使用EL表达式, 否则为纯文本.
4. type : 设定这个attribute的类型, jsp容器会把结果自动转换成这个类.
如此，jsp名就是标签名，例如这个jsp叫 select.jsp，那么它的用法就是
<sys:select cls="formselect" name="MODULE_TYPE" typeCode="HOME_MODULE_TYPE" defaultValue="${record.MODULE_TYPE }" />
附上一个实际例子
treeselect.tag
<%@ tag language="java" pageEncoding="UTF-8"%><%@ include file="/WEB-INF/views/include/taglib.jsp"%><%@ attribute name="id" type="java.lang.String" required="true" description="编号"%><%@ attribute name="name" type="java.lang.String" required="true" description="隐藏域名称（ID）"%><%@ attribute name="value" type="java.lang.String" required="true" description="隐藏域值（ID）"%><%@ attribute name="labelName" type="java.lang.String" required="true" description="输入框名称（Name）"%><%@ attribute name="labelValue" type="java.lang.String" required="true" description="输入框值（Name）"%><%@ attribute name="title" type="java.lang.String" required="true" description="选择框标题"%><%@ attribute name="url" type="java.lang.String" required="true" description="树结构数据地址"%><%@ attribute name="checked" type="java.lang.Boolean" required="false" description="是否显示复选框，如果不需要返回父节点，请设置notAllowSelectParent为true"%><%@ attribute name="extId" type="java.lang.String" required="false" description="排除掉的编号（不能选择的编号）"%><%@ attribute name="isAll" type="java.lang.Boolean" required="false" description="是否列出全部数据，设置true则不进行数据权限过滤（目前仅对Office有效）"%><%@ attribute name="notAllowSelectRoot" type="java.lang.Boolean" required="false" description="不允许选择根节点"%><%@ attribute name="notAllowSelectParent" type="java.lang.Boolean" required="false" description="不允许选择父节点"%><%@ attribute name="module" type="java.lang.String" required="false" description="过滤栏目模型（只显示指定模型，仅针对CMS的Category树）"%><%@ attribute name="selectScopeModule" type="java.lang.Boolean" required="false" description="选择范围内的模型（控制不能选择公共模型，不能选择本栏目外的模型）（仅针对CMS的Category树）"%><%@ attribute name="allowClear" type="java.lang.Boolean" required="false" description="是否允许清除"%><%@ attribute name="allowInput" type="java.lang.Boolean" required="false" description="文本框可填写"%><%@ attribute name="cssClass" type="java.lang.String" required="false" description="css样式"%><%@ attribute name="cssStyle" type="java.lang.String" required="false" description="css样式"%><%@ attribute name="smallBtn" type="java.lang.Boolean" required="false" description="缩小按钮显示"%><%@ attribute name="hideBtn" type="java.lang.Boolean" required="false" description="是否显示按钮"%><%@ attribute name="disabled" type="java.lang.String" required="false" description="是否限制选择，如果限制，设置为disabled"%><%@ attribute name="dataMsgRequired" type="java.lang.String" required="false" description=""%><div class="input-append"><input id="${id}Id" name="${name}" class="${cssClass}" type="hidden" value="${value}"/><input id="${id}Name" name="${labelName}" ${allowInput?'':'readonly="readonly"'} type="text" value="${labelValue}" data-msg-required="${dataMsgRequired}"class="${cssClass}" style="${cssStyle}"/><a id="${id}Button" href="javascript:" class="btn ${disabled} ${hideBtn ? 'hide' : ''}" style="${smallBtn?'padding:4px 2px;':''}"> <i class="icon-search"></i> </a> </div><script type="text/javascript">$("#${id}Button, #${id}Name").click(function(){// 是否限制选择，如果限制，设置为disabledif ($("#${id}Button").hasClass("disabled")){return true;}// 正常打开top.$.jBox.open("iframe:${ctx}/tag/treeselect?url="+encodeURIComponent("${url}")+"&module=${module}&checked=${checked}&extId=${extId}&isAll=${isAll}", "选择${title}", 300, 420, {ajaxData:{selectIds: $("#${id}Id").val()},buttons:{"确定":"ok", ${allowClear?"\"清除\":\"clear\", ":""}"关闭":true}, submit:function(v, h, f){if (v=="ok"){var tree = h.find("iframe")[0].contentWindow.tree;//h.find("iframe").contents();var ids = [], names = [], nodes = [];if ("${checked}" == "true"){nodes = tree.getCheckedNodes(true);}else{nodes = tree.getSelectedNodes();}for(var i=0; i<nodes.length; i++) {//<c:if test="${checked && notAllowSelectParent}">if (nodes[i].isParent){continue; // 如果为复选框选择，则过滤掉父节点}//</c:if><c:if test="${notAllowSelectRoot}">if (nodes[i].level == 0){top.$.jBox.tip("不能选择根节点（"+nodes[i].name+"）请重新选择。");return false;}//</c:if><c:if test="${notAllowSelectParent}">if (nodes[i].isParent){top.$.jBox.tip("不能选择父节点（"+nodes[i].name+"）请重新选择。");return false;}//</c:if><c:if test="${not empty module && selectScopeModule}">if (nodes[i].module == ""){top.$.jBox.tip("不能选择公共模型（"+nodes[i].name+"）请重新选择。");return false;}else if (nodes[i].module != "${module}"){top.$.jBox.tip("不能选择当前栏目以外的栏目模型，请重新选择。");return false;}//</c:if>ids.push(nodes[i].id);names.push(nodes[i].name);//<c:if test="${!checked}">break; // 如果为非复选框选择，则返回第一个选择 </c:if>}$("#${id}Id").val(ids.join(",").replace(/u_/ig,""));$("#${id}Name").val(names.join(","));}//<c:if test="${allowClear}">else if (v=="clear"){$("#${id}Id").val("");$("#${id}Name").val("");}//</c:if>if(typeof ${id}TreeselectCallBack == 'function'){${id}TreeselectCallBack(v, h, f);}}, loaded:function(h){$(".jbox-content", top.document).css("overflow-y","hidden");}});});</script>