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Struts2 OGNL表达式实例详解

程序员文章站 2024-02-27 21:28:51
object graph navigation language:对象图导航语言,就是用点来访问成员变量

object graph navigation language:对象图导航语言,就是用点来访问成员变量

<s:property value="cat.name"/> 

例1:

struts.xml:

<package name="ognl" namespace="/ognl" extends="struts-default"> 
  <action name="og1" class="cn.edu.hpu.action.ognlaction1"> 
  <result>/ognl.jsp</result> 
  </action> 
</package> 

ognlaction1.java:

package cn.edu.hpu.action; 
import com.opensymphony.xwork2.actionsupport; 
public class ognlaction1 extends actionsupport{ 
  private string username; 
  private string password; 
  public string getusername() { 
    return username; 
  }  
  public void setusername(string username) { 
    this.username = username; 
  } 
  public string getpassword() { 
    return password; 
  } 
  public void setpassword(string password) { 
    this.password = password; 
  } 
  @override 
  public string execute() throws exception { 
    // todo auto-generated method stub 
    return super.execute(); 
  } 
} 

访问链接:

<a href="<%=basepath%>ognl/og1?username=jack&&password=111" rel="external nofollow" >ognl</a><br/> 

结果界面:

ognl success!!<br/> 
  <ol> 
    <li>访问值栈中的action的普通属性1=<s:property value="username"/></li> 
    <li>访问值栈中的action的普通属性2=<s:property value="password"/></li> 
  </ol> 
  <s:debug></s:debug> 

结果显示:

ognl success!!

访问值栈中的action的普通属性1=jack

访问值栈中的action的普通属性2=111

[debug]
ps:点击[debug]可以查看到栈值中有username与password

例2:

struts.xml:

<package name="ognl" namespace="/ognl" extends="struts-default"> 
 <action name="user2" class="cn.edu.hpu.action.useraction2" method="add"> 
   <result name="success">/ognl.jsp</result> 
  </action> 
</package> 

useraction2.java:

package cn.edu.hpu.action;  
import cn.edu.hpu.mode.user; 
public class useraction2 {  
  private user user;    
  public string add(){ 
    system.out.println("name="+user.getname()); 
    system.out.println("age="+user.getage()); 
    return "success"; 
  } 
  public user getuser() { 
    return user; 
  } 
  public void setuser(user user) { 
    this.user = user; 
  }   
} 

user.java:

package cn.edu.hpu.mode;  
public class user {      
  private string name; 
  private int age;   
  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; 
  }    
} 

链接:

访问user属性

<a href="<%=basepath%>ognl/user2?user.name=tom&&user.age=21" rel="external nofollow" >ognl2</a><br/> 

(只有你传user.xxxx才能构造)

结果页面:

<%@taglib uri="/struts-tags" prefix="s" %> 
<!doctype html public "-//w3c//dtd html 4.01 transitional//en"> 
<html> 
 <head> 
  <base href="<%=basepath%>" rel="external nofollow" > 
  <title>my jsp 'ognl.jsp' starting page</title> 
 </head> 
  
 <body> 
  ognl success!!<br/> 
  <ol> 
    <li>访问值栈中对象的普通属性(get set 方法 ): 
    <br/> 
 user-age:<s:property value="user.age"/>|<s:property value="user['age']"/></li> 
  </ol> 
  <s:debug></s:debug> 
 </body> 
</html> 

显示结果:

ognl success!!

访问值栈中对象的普通属性(get set 方法 ):

user-age:21|21

[debug]

点击[debug]可以查看到栈值中有user对象的存在

例3:

struts.xml

<package name="ognl" namespace="/ognl" extends="struts-default"> 
  <action name="cat1" class="cn.edu.hpu.ognl.ognlaction2"> 
   <result name="success">/ognl.jsp</result> 
 </action> 
</package> 

ognlaction2.java:

package cn.edu.hpu.ognl; 
 
import cn.edu.hpu.mode.cat;  
import com.opensymphony.xwork2.actionsupport; 
public class ognlaction2 extends actionsupport{   
  private cat cat; 
  public cat getcat() { 
    return cat; 
  } 
  public void setcat(cat cat) { 
    this.cat = cat; 
  } 
  public string execute(){ 
    return "success"; 
  } 
  public string m(){ 
    return "hello"; 
  } 
} 

cat.java:

package cn.edu.hpu.mode;  
public class cat {  
  private dog friend; 
  public dog getfriend() { 
    return friend; 
  } 
  public void setfriend(dog friend) { 
    this.friend = friend; 
  }  
  public string miaomiao(){ 
    return "miaomiao"; 
  } 
} 

dog.java:

package cn.edu.hpu.mode;   
public class dog {    
  private string name;    
  public dog(){      
  }    
  public dog(string name){ 
    super(); 
    this.name=name; 
  }   
  public string getname() { 
    return name; 
  } 
  public void setname(string name) { 
    this.name = name; 
  }  
  @override 
  public string tostring() { 
    // todo auto-generated method stub 
    return "dog:"+name; 
  } 
} 

链接:

 访问cat属性

<a href="<%=basepath%>ognl/cat1?cat.friend.name=littleboy" rel="external nofollow" >ognl3</a><br/>

结果页面:

<li>访问值栈中对象的普通属性(get set 方法 ): 
    <br/> 
    cat-friend-name:<s:property value="cat.friend.name"/></li> 

结果:

访问值栈中对象的普通属性(get set 方法 ):

cat-friend-name:littleboy

观察[debug],发现只有cat在值栈中,说明通过cat联系到dog,取得dog中的属性

访问cat方法:

<a href="<%=basepath%>ognl/cat1" rel="external nofollow" rel="external nofollow" >ognl4</a><br/>

结果页面:

<li>访问值栈中对象的普通方法: 
    <br/> 
    cat-miaomiao:<s:property value="cat.miaomiao()"/></li> 

结果:

访问值栈中对象的普通属性:

cat-miaomiao:miaomiao

访问action的普通方法:

<a href="<%=basepath%>ognl/cat1" rel="external nofollow" rel="external nofollow" >ognl5</a><br/> 

结果页面:

<li>访问值栈中action的普通方法: 
    <br/> 
    action-m():<s:property value="m()"/></li> 

结果:

访问值栈中acion的普通方法:

action-m():hello

总结

以上就是本文关于struts2 ognl表达式实例详解的全部内容,希望对大家有所帮助。有什么问题可以随时留言,欢迎大家交流讨论。