JSTL标签库 #
JSTL主要有五大类标签库
- core标签库(核心标签库),包括通用标签(输出标签),流程控制和循环控制标签
- fmt标签库,包括格式化,国际格式化标签等
- fn标签库,函数标签库
- XML标签库,关于XML操作的标签库
- SQL标签库,操作数据库标签
core标签库用法 #
使用core标签前必须添加taglie指令
%@ taglib prefix=“c” uri=“http://java.sun.com/jsp/jstl/core" %>
- <c:set>在某个范围设定某个值
<c:set value=“表达式” var=“varname” [scope=“request|page|session|application”]></c:set>
<c:set value="${1+2 }" var="variable"></c:set>
${variable }
- <c:out>把表达式的结构输出到页面中
<c:out value=“表达式” [escapeXml=“true|false”]></c:out>
<c:set value="${1+2 }" var="variable"></c:set>
<c:out value="${variable }"></c:out>
- <c:if>条件判断
<c:if test=“判断条件” [var=“varname”] [scope=“request|page|session|application”]> 条件为真执行的语句 </c:if>
<c:if test="${1<2 }" var="result">
<c:out value="${result }"></c:out>
</c:if>
- <c:choose>,<c:when>,<c:otherwise>流程控制标签
<c:choose> <c:when test=“表达式”> 表达式为真执行的语句 </c:when> [<c:otherwise> 表达式为假执行的语句 </c:otherwise>] </c:choose>
<c:when>必须在<c:otherwise>前边,<c:choose>可以添加多个<c:choose>,类似于if else if写法
<c:set value="8" var="variable1"></c:set>
<c:set value="9" var="variable2"></c:set>
<c:choose>
<c:when test="${variable1%2==0 }">
<c:out value="variable1:偶数"></c:out>
<c:choose>
<c:when test="${variable2%2==0 }">
<c:out value="variable2:偶数"></c:out>
</c:when>
<c:otherwise>
<c:out value="variable2:奇数"></c:out>
</c:otherwise>
</c:choose>
</c:when>
<c:otherwise>
<c:out value="variable1:奇数"></c:out>
</c:otherwise>
</c:choose>
- <c:forEach>迭代标签
<c:forEach [var=“varname”] [varStatus=“varStatusName”] [begin=“开始”] [end=“结束”] [step=“步数”]> java or html code </c:forEach>
<table>
<tr>
<td>行号1</td>
<td>行号2</td>
<td>当前迭代项</td>
<td>是否第一项</td>
<td>是否最后一项</td>
<td>结果</td>
</tr>
<c:forEach var="i" varStatus="j" begin="1" end="10" step="2">
<tr>
<td>${j.index }</td>
<td>${j.count }</td>
<td>${j.current }</td>
<td>${j.first }</td>
<td>${j.last }</td>
<td>${i }</td>
</tr>
</c:forEach>
</table>
<c:forEach item=“collection” [varStatus=“varStatusName” [begin=“开始”] [end=“结束”] [step=“步数”]]> java or heml code </c:forEach>
<%
List list=new ArrayList();
list.add("zhangsan");
list.add("lisi");
list.add("wangwu");
list.add("liuliu");
pageContext.setAttribute("collection", list);
%>
<table>
<tr>
<td>行号1</td>
<td>行号2</td>
<td>当前迭代项</td>
<td>是否第一项</td>
<td>是否最后一项</td>
<td>姓名</td>
</tr>
<c:forEach items="${collection }" var="i" varStatus="j">
<tr>
<td>${j.index }</td>
<td>${j.count }</td>
<td>${j.current }</td>
<td>${j.first }</td>
<td>${j.last }</td>
<td>${i }</td>
</tr>
</c:forEach>
</table>
- <c;forTokens>字符串分割标签
<c:forTokens items=“字符串” delims=“分割符” [var=“別名”] [varStatus=“varStatusName”] [begin=“开始”] [end=“结束”] [step=“步数”]> java or html code </c:forTokens>
<table>
<tr>
<td>行号1</td>
<td>行号2</td>
<td>当前迭代项</td>
<td>是否第一项</td>
<td>是否最后一项</td>
<td>子字符串</td>
</tr>
<c:forTokens items="this is a jstl code" delims=" " var="i" varStatus="j">
<tr>
<td>${j.index }</td>
<td>${j.count }</td>
<td>${j.current }</td>
<td>${j.first }</td>
<td>${j.last }</td>
<td>${i }</td>
</tr>
</c:forTokens>
- <c;remove>删除某个范围内的值
<c:remove var=“varname” [scope=“request|page|session|application”]/>
<%
pageContext.setAttribute("varname1", "one");
request.setAttribute("varname2", "two");
session.setAttribute("varname3", "three");
application.setAttribute("varname4", "four");
%>
<table>
<tr>
<th>pageContext</th>
<th>request</th>
<th>session</th>
<th>application</th>
</tr>
<tr>
<td>${varname1 }</td>
<td>${varname2 }</td>
<td>${varname3 }</td>
<td>${varname4 }</td>
</tr>
</table>
<c:remove var="varname1"/>
<c:remove var="varname2"/>
<c:remove var="varname3"/>
<c:remove var="varname4"/>
<c:out value="删除后"></c:out><br>
<table>
<tr>
<th>pageContext</th>
<th>request</th>
<th>session</th>
<th>application</th>
</tr>
<tr>
<td>${varname1 }</td>
<td>${varname2 }</td>
<td>${varname3 }</td>
<td>${varname4 }</td>
</tr>
</table>
- <c:catch>抛出异常标签
<c:catch [var=“varname”]> code </c:catch>
<c:catch var="error">
<%
int[] arr=new int[4];
int j=arr[5];
%>
</c:catch>
<c:out value="错误信息:${error }"></c:out><br>
<c:catch var="error1">
<%
int j=5/0;
%>
</c:catch>
<c:out value="错误信息:${error1 }"></c:out>
- <c:param>向导入的页面传入参数,与<c:import>结合使用
<c:param name=“paramName” value=“paramValue”></c:param>
- <c:import>导入静|动态文件
<c:import url=“url” [context=“context”] [var=“varname”] [scope=“request|page|session|application”] [charEncoding=“coding”]> [<c:param name=“paramName” [value=“valueName”]></c:param>] </c:import>
<c:import url="https://www.baidu.com/s">
<c:param name="wd" value="java"/>
</c:import>
- <c:redirect>重定向另一个页面
<c:redirect url=“url” [contex=“context”]> [<c:param name=“paramName” [value=“valueName”]></c:param>] </c:redirect>
<c:redirect url="https://www.baidu.com/s">
<c:param name="wd" value="java"/>
</c:redirect>
- <c:url>生成一个url
<c:url value=“url” [context=“context”] var=“varname” [scope=“request|page|session|application”]> [<c:param name=“paramName” [value=“valueName”]></c:param>] </c:url>
<c:url value="https://www.baidu.com/s" var="varname">
<c:param name="wd" value="java"></c:param>
</c:url>
<c:out value="${varname }"></c:out>
<br>
<c:url value="/index.jsp" var="varname"></c:url>
<c:out value="${varname }"></c:out>
- 表格合并
<div class="page-inner mt--5" style="margin-bottom: 1rem;">
<div class="row mt--2">
<div class="col-md-12">
<div class="card full-height">
<div class="card-header">
<div class="card-head-row">
<div class="card-title">工作事项配置</div>
</div>
</div>
<div class="card-body">
<form class="form-horizontal">
<div class="row form-group">
<div class="col-md-12">
<table class="table table-bordered table-striped">
<thead>
<tr>
<th>阶段</th>
<th>工作事项</th>
<th>名称</th>
<th>排序</th>
<th>责任人</th>
<th>描述</th>
<th>编辑</th>
</tr>
</thead>
<tbody>
<c:forEach items="${projectWorkStageConfigVoList}" var="ProjectWorkStageConfigVo" varStatus="StatusWorkStageConfigVo">
<c:forEach items="${ProjectWorkStageConfigVo.projectPhaseConfigVoList}" var="ProjectPhaseConfigVo" varStatus="StatusPhaseConfigVo">
<c:forEach items="${ProjectPhaseConfigVo.projectPhaseConfigList}" var="ProjectPhaseConfig" varStatus="StatusConfig">
<tr>
<c:choose>
<c:when test="${ StatusConfig.first && StatusPhaseConfigVo.first}">
<td rowspan="${fn:length(ProjectWorkStageConfigVo.projectPhaseConfigVoList) * fn:length(ProjectPhaseConfigVo.projectPhaseConfigList)}">
${ProjectWorkStageConfigVo.workStageName}
</td>
</c:when>
</c:choose>
<c:choose>
<c:when test="${ StatusConfig.first}">
<td rowspan="${fn:length(ProjectPhaseConfigVo.projectPhaseConfigList)}">
${ProjectPhaseConfigVo.projectPhaseName}
</td>
</c:when>
</c:choose>
<td >${ProjectPhaseConfig.parName} </td>
<td >${ProjectPhaseConfig.sorting} </td>
<td >${ProjectPhaseConfig.parValues} </td>
<td >${ProjectPhaseConfig.remark} </td>
<td>
<button type="button" onclick="editProjectPhaseConfig('${ProjectPhaseConfig.id}');"
style="margin-left: 5px;"
class="btn btn-primary btn-xs tooltips"
data-placement="bottom" data-original-title="编辑">
<i class="fa fa-pen"></i>
</button>
</td>
</tr>
</c:forEach>
</c:forEach>
</c:forEach>
</tbody>
</table>
</div>
</div>
</form>
</div>
</div>
</div>
</div>
</div>