EL表达式简介_动力节点Java学院整理

　<%
   String name = "Ding";
   request.setAttribute("personName", name);
  %>  
  ${personName }

 <%
  Person p = new Person("Ding",25);
   request.setAttribute("person", p);
  %>  
  ${person }   

  ${person.name } 

public class Person { 
  private String name;
  private int age;
 private Address address; 
 。。。省略各个属性的get和set方法
  } 
 public class Address {
 private String city;  
  。。。省略city属性的get和set方法
 }

 <%
    Person p = new Person();
   Address a = new Address();
   a.setCity("Amoy");
   p.setAddress(a);
   request.setAttribute("person", p);
  %> 
  ${person.address.city } 

 ${pageContext.request.contextPath}

 <%
   List persOnList= new ArrayList();
  personList.add(new Person("Ding",25));
  personList.add(new Person("LRR",24));
  request.setAttribute("persons",personList);
  %>  
  ${persons[0].name } love ${persons[1].name}

 <%
   Map persOnMap= new HashMap();
  personMap.put("p1",new Person("Ding",25));
   personMap.put("p2",new Person("LRR",24));   
  request.setAttribute("pMap", personMap);
  %>  
  ${pMap.p1.name } 

  love 

  ${pMap['p2'].name }

 <%
   request.setAttribute("username", "root");
   request.setAttribute("password", "123");
  %>
  ${username == "root" && password == "123" }

 <%
   request.setAttribute("person", null);
    request.setAttribute("address", "");
   request.setAttribute("user", new User());
  %>
  ${empty(person)}  

  ${empty(address)} 

  ${empty(user)}   

 <%
   User user = new User();
   user.setUsername("fjdingsd");
   pageContext.setAttribute("user", user);
  %>  
 欢迎您：${user!=null &＃63; user.username : '' }

<%
   request.setAttribute("gender", "female");
  %>
  男    
  女