EL表达式简单取值

EL表达式简单取值

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前提

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>  
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>  

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1. 直接获取数据

后台直接传递 String name = “zyc”;

${name}   

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2. 循环获取List数据

//后台代码List集合
List list = new ArrayList();   
list.add("I");  
list.add("L");  
list.add("O");  
list.add("V");
list.add("E"); 

${list[0]},
${list[1]},
${list[2]},
${list[3]}

<c:forEach items="${list}" var="item" varStatus="status">  
    <li>
        <a target="_black">
            ${item}
        a>
    li> 
c:forEach>

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3.循环获取List < Object >数据

//后台数据
List list = new ArrayList<>();   
list.add(new Student("Tom01",20));  
list.add(new Student("Tom02",21));  
list.add(new Student("Tom03",22));  

<c:forEach items="${list}" var="item" varStatus="status">  
    <li>
        姓名:${item.name},年龄:${item.age}
    li> 
c:forEach>

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4.循环获取Map< String,List < Object > >数据

//后台数据
Map<String, List> map = new HashMap<>();
List<Student> list = new ArrayList<>();   
list.add(new Student("Tom01",20));  
list.add(new Student("Tom02",21));  
list.add(new Student("Tom03",22)); 
map.put("studen01",list);

List<Student> list1 = new ArrayList<>();   
list.add(new Student("Josh01",23));  
list.add(new Student("Josh02",24));  
list.add(new Student("Josh03",25)); 
map.put("studen02",list1);

List<Student> list2 = new ArrayList<>();   
list.add(new Student("Jack01",26));  
list.add(new Student("Jack02",27));  
list.add(new Student("Jack03",28)); 
map.put("studen03",list2);

<c:forEach items="${map}" var="item">
 ${item.key}
 ${item.value}
c:forEach>


<c:forEach items="${map['student01']}" var="item" varStatus="status">  
    <li>
        姓名:${item.name},年龄:${item.age}
    li> 
c:forEach>