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  • 小峰servlet/jsp(6)jstl核心标签库

    一、引入jstl

    需要jstl.jar;standard.jar;

    二、jstl核心标签库:

    c:out               内容输出标签;

    c:set             用来设置4种属性范围值的标签;

    c:remove         用来删除指定范围中的属性;

    c:catch        用来处理程序中产生的异常;

    c:if          用来条件判断;

    c:choose/c:when/c:otherwise 用来多条件判断;

    c:forEach        用来遍历数组或者集合;

    c:fortokens      分隔输出;

    c:import         导入页面;

    c:url           生成一个url地址;

    c:redirect        客户端跳转

    c:out:

     1 <%@ page language="java" contentType="text/html; charset=UTF-8"
     2     pageEncoding="UTF-8"%>
     3 <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
     4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
     5 <html>
     6 <head>
     7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
     8 <title>Insert title here</title>
     9 </head>
    10 <body>
    11 <%
    12     pageContext.setAttribute("people","张三");
    13 %>
    14 <h2><c:out value="${people}"></c:out></h2>
    15 <h2><c:out value="${people2}" default="某人"></c:out></h2>
    16 </body>
    17 </html>
    View Code

    c:set

     1 <body>
     2 <c:set var="people" value="张三" scope="request"></c:set>
     3 <h2><c:out value="${people}"></c:out></h2>
     4 <jsp:useBean id="people2" class="com.java1234.model.People" scope="page"></jsp:useBean>
     5 <c:set property="id" target="${people2 }" value="007"></c:set>
     6 <c:set property="name" target="${people2 }" value="王二小"></c:set>
     7 <c:set property="age" target="${people2 }" value="16"></c:set>
     8 <h2>编号:${people2.id }</h2>
     9 <h2>姓名:${people2.name }</h2>
    10 <h2>年龄:${people2.age }</h2>
    11 </body>
    View Code

     c:remove:

    1 <body>
    2 <c:set var="people" value="张三" scope="request"></c:set>
    3 <h2><c:out value="${people}" default="没人啊"></c:out></h2>
    4 <c:remove var="people" scope="request"/>
    5 <h2><c:out value="${people}" default="没人啊"></c:out></h2>
    6 </body>
    View Code

     c:catch:

    1 <body>
    2 <c:catch var="errMsg">
    3     <%
    4         int a=1/0;
    5     %>
    6 </c:catch>
    7 <h2>异常信息:${errMsg }</h2>
    8 </body>
    View Code

    c:if:

     1 <body>
     2 <jsp:useBean id="people" class="com.java1234.model.People" scope="page"></jsp:useBean>
     3 <c:set property="id" target="${people }" value="007"></c:set>
     4 <c:set property="name" target="${people }" value="王二小"></c:set>
     5 <c:set property="age" target="${people }" value="16"></c:set>
     6 <c:if test="${people.name=='王二小' }" var="r" scope="page">
     7     <h2>是王二小</h2>
     8 </c:if>
     9 <c:if test="${people.age<18 }">
    10     <h2>是未成年</h2>
    11 </c:if>
    12 </body>
    View Code

    c:choose/c:when/c:otherwise:  多条件判断:

     1 <body>
     2 <jsp:useBean id="people" class="com.java1234.model.People" scope="page"></jsp:useBean>
     3 <c:set property="id" target="${people }" value="007"></c:set>
     4 <c:set property="name" target="${people }" value="王二小"></c:set>
     5 <c:set property="age" target="${people }" value="19"></c:set>
     6 <c:choose>
     7     <c:when test="${people.age<18 }">
     8         <h2>小于18</h2>
     9     </c:when>
    10     <c:when test="${people.age==18 }">
    11         <h2>等于18</h2>
    12     </c:when>
    13     <c:otherwise>
    14         <h2>大于18</h2>
    15     </c:otherwise>
    16 </c:choose>
    17 </body>
    View Code

    c:forEach:

     1 <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
     2 <%@ page import="com.java1234.model.*"%>
     3 <%@ page import="java.util.*"%>
     4 <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
     5 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
     6 <html>
     7 <head>
     8 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
     9 <title>Insert title here</title>
    10 </head>
    11 <body>
    12 <%
    13     String dogs[]={"小黑","小黄","小白","小小"};
    14     pageContext.setAttribute("dogs",dogs);
    15 %>
    16 <c:forEach var="dog" items="${dogs }">
    17     ${dog }
    18 </c:forEach>
    19 <hr/>
    20 <c:forEach var="dog" items="${dogs }" step="2">
    21     ${dog }
    22 </c:forEach>
    23 <hr/>
    24 <c:forEach var="dog" items="${dogs }" begin="1" end="2"><!--begin end是索引值-->
    25     ${dog }
    26 </c:forEach>
    27 <hr/>
    28 <%
    29     List<People> pList=new ArrayList<People>();
    30     pList.add(new People(1,"张三",10));
    31     pList.add(new People(2,"李四",20));
    32     pList.add(new People(3,"王五",30));
    33     pageContext.setAttribute("pList",pList);
    34 %>
    35 <table>
    36     <tr>
    37         <th>编号</th>
    38         <th>姓名</th>
    39         <th>年龄</th>
    40     </tr>
    41     <c:forEach var="p" items="${pList }">
    42         <tr>
    43             <td>${p.id }</td>
    44             <td>${p.name }</td>
    45             <td>${p.age }</td>
    46         </tr>
    47     </c:forEach>
    48 </table>
    49 </body>
    50 </html>
    View Code

    c:forTokens: 分隔输出:

     1 <body>
     2 <%
     3     String str1="www.java1234.com";
     4     String str2="张三,李四,王五";
     5     pageContext.setAttribute("str1",str1);
     6     pageContext.setAttribute("str2",str2);
     7 %>
     8 <c:forTokens items="${str1 }" delims="." var="s1">
     9     ${s1 }
    10 </c:forTokens>
    11 <hr/>
    12 <c:forTokens items="${str2 }" delims="," var="s2">
    13     ${s2 }
    14 </c:forTokens>
    15 </body>
    View Code

    c:import: 导入页面; 有点像jsp include:

    1 <body>
    2 <c:import url="c_forEach.jsp"></c:import>
    3 <c:import url="c_if.jsp"></c:import>
    4 </body>
    View Code

    c:url:

    1 <body>
    2 <c:url value="http://www.baidu.com" var="url">
    3     <c:param name="name" value="xiaoming"></c:param>
    4     <c:param name="age" value="26"></c:param>
    5 </c:url>
    6 <a href="${url }">百度</a>
    7 </body>
    View Code

    c:redirect 客户端跳转:

     1 <body>
     2 <c:redirect url="target.jsp">
     3     <c:param name="name" value="xiaoming"></c:param>
     4     <c:param name="age" value="26"></c:param>
     5 </c:redirect>
     6 </body>
     7 
     8 target.jsp:
     9 <body>
    10 <h2>姓名:${param.name }</h2>
    11 <h2>年龄:${param.age }</h2>
    12 </body>
    View Code
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  • 原文地址:https://www.cnblogs.com/tenWood/p/6506320.html
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