package bean;
public class Person {
public String name;
public int age;
public Address address;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address = address;
}
}
package bean;
public class Address {
public String name="aa我是地址啊";
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@page import="bean.*,java.util.*"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>el表达式</title>
</head>
<body>
<%
request.setAttribute("name", "aaa");
%>
<!-- pageContext.findAttribute("name") page request session application-->
${name }
<!-- 在jsp页面中，使用el表达式可以获取bean的属性 -->
<%
Person p = new Person();
p.setAge(12);
request.setAttribute("person", p);
%>
${person.age }
<!-- 在jsp页面中，使用el表达式可以获取bean中的。。。。。。。。。的属性 -->
<%
Person person = new Person();
Address address = new Address();
person.setAddress(address);
request.setAttribute("person", person);
%>
${person.address.name }
<!-- 在jsp页面中，使用el表达式获取list集合中指定位置的数据 -->
<%
Person p1 = new Person();
p1.setName("aa111");
Person p2 = new Person();
p2.setName("bb");
List list = new ArrayList();
list.add(p1);
list.add(p2);
request.setAttribute("list", list);
%>
${list[0].name }
<!-- 在jsp页面中，使用el表达式获取map集合的数据 -->
<%
Map map = new HashMap();
map.put("a", "aaaaxxx");
map.put("b", "bbbb");
map.put("c", "cccc");
map.put("1", "aaaa1111");
request.setAttribute("map", map);
%>
${map.a } ${map["1"] }
<!-- 利用el表达式获取web应用的名称 -->
<a href="${pageContext.request.contextPath }/index.jsp">点点</a>
<!-- 注意:如果访问bean不存在的属性，会抛 Property 'username' not found on type cn.itcast.Person -->
<%-- ${person.username }--%>
</body>
</html>
时间： 2024-12-30 19:42:12