從一個客戶端的請求開始：
先經過Web.xml 到達struts.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<constant name="struts.enable.DynamicMethodInvocation"
value="false" />
自動編譯
<constant name="struts.devMode" value="true" />
訪問靜態屬性和方法要設置的
<constant name="struts.ognl.allowStaticMethodAccess"
value="true">
</constant>
模塊包含，包含ognl.xml
<include file="/com/bjsxt/struts2/ognl/ognl.xml" />
</struts>被包含的ognl.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<package name="ognl" extends="struts-default">
<action name="ognl" class="com.bjsxt.struts2.ognl.OgnlAction">
<result>/ognl.jsp</result>
</action>
<action name="test" class="com.bjsxt.struts2.ognl.TestAction">
<result type="chain">ognl</result>
</action>
</package>
</struts>OgnlAction 類：
package com.bjsxt.struts2.ognl;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.opensymphony.xwork2.ActionSupport;
public class OgnlAction extends ActionSupport {
private Cat cat;
private Map<String, Dog> dogMap = new HashMap<String, Dog>();
private Set<Dog> dogs = new HashSet<Dog>();
private String password;
private User user;
private String username;
private List<User> users = new ArrayList<User>();
public OgnlAction() {
users.add(new User(1));
users.add(new User(2));
users.add(new User(3));
dogs.add(new Dog("dog1"));
dogs.add(new Dog("dog2"));
dogs.add(new Dog("dog3"));
dogMap.put("dog100", new Dog("dog100"));
dogMap.put("dog101", new Dog("dog101"));
dogMap.put("dog102", new Dog("dog102"));
}
public String execute() {
return SUCCESS;
}
public Cat getCat() {
return cat;
}
public Map<String, Dog> getDogMap() {
return dogMap;
}
public Set<Dog> getDogs() {
return dogs;
}
public String getPassword() {
return password;
}
public User getUser() {
return user;
}
public String getUsername() {
return username;
}
public List<User> getUsers() {
return users;
}
public String m() {
return "hello";
}
public void setCat(Cat cat) {
this.cat = cat;
}
public void setDogMap(Map<String, Dog> dogMap) {
this.dogMap = dogMap;
}
public void setDogs(Set<Dog> dogs) {
this.dogs = dogs;
}
public void setPassword(String password) {
this.password = password;
}
public void setUser(User user) {
this.user = user;
}
public void setUsername(String username) {
this.username = username;
}
public void setUsers(List<User> users) {
this.users = users;
}
}Cat類：
package com.bjsxt.struts2.ognl;
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類：
package com.bjsxt.struts2.ognl;
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() {
return "dog: " + name;
}
}S類：
package com.bjsxt.struts2.ognl;
public class S {
public static String STR = "STATIC STRING";
public static String s() {
return "static method";
}
}User類：
package com.bjsxt.struts2.ognl;
public class User {
private int age = 8;
public User() {
}
public User(int age) {
super();
this.age = age;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "user" + age;
}
}最重要的ognl.jsp（包含訪問值棧中各種元素的方法）：
<body>
<ol>
<li>訪問值棧中的action的普通屬性: username = <s:property value="username"/> </li>
<li>訪問值棧中對象的普通屬性(get set方法)：<s:property value="user.age"/> | <s:property value="user['age']"/> | <s:property value="user[\"age\"]"/> | wrong: <%--<s:property value="user[age]"/>--%></li>
<li>訪問值棧中對象的普通屬性(get set方法): <s:property value="cat.friend.name"/></li>
<li>訪問值棧中對象的普通方法：<s:property value="password.length()"/></li>
<li>訪問值棧中對象的普通方法：<s:property value="cat.miaomiao()" /></li>
<li>訪問值棧中action的普通方法：<s:property value="m()" /></li>
<hr />
<li>訪問靜態方法：<s:property value="@com.bjsxt.struts2.ognl.S@s()"/></li>
<li>訪問靜態屬性：<s:property value="@com.bjsxt.struts2.ognl.S@STR"/></li>
<li>訪問Math類的靜態方法：<s:property value="@@max(2,3)" /></li>
<hr />
<li>訪問普通類的構造方法：<s:property value="new com.bjsxt.struts2.ognl.User(8)"/></li>
<hr />
<li>訪問List:<s:property value="users"/></li>
<li>訪問List中某個元素:<s:property value="users[1]"/></li>
<li>訪問List中元素某個屬性的集合:<s:property value="users.{age}"/></li>
<li>訪問List中元素某個屬性的集合中的特定值:<s:property value="users.{age}[0]"/> | <s:property value="users[0].age"/></li>
<li>訪問Set:<s:property value="dogs"/></li>
<li>訪問Set中某個元素:<s:property value="dogs[1]"/></li>
<li>訪問Map:<s:property value="dogMap"/></li>
<li>訪問Map中某個元素:<s:property value="dogMap.dog101"/> | <s:property value="dogMap['dog101']"/> | <s:property value="dogMap[\"dog101\"]"/></li>
<li>訪問Map中所有的key:<s:property value="dogMap.keys"/></li>
<li>訪問Map中所有的value:<s:property value="dogMap.values"/></li>
<li>訪問容器的大小：<s:property value="dogMap.size()"/> | <s:property value="users.size"/> </li>
<hr />
<li>投影(過濾)：<s:property value="users.{?#this.age==1}[0]"/></li>
<li>投影：<s:property value="users.{^#this.age>1}.{age}"/></li>
<li>投影：<s:property value="users.{$#this.age>1}.{age}"/></li>
<li>投影：<s:property value="users.{$#this.age>1}.{age} == null"/></li>
<hr />
<li>[]:<s:property value="[0].username"/></li>
</ol>
<s:debug></s:debug>
struts2提供了一個非常好的調試方法.就是在頁面上添加一個debug標籤..它會自動幫我們將一些信息顯示在頁面上；這個值棧又分爲兩種.Value Stack Contents 和 Stack Context .
(1).Value Stack Contents 裏面的信息我們可以用 <s:property value="sss"> 這樣來直接訪問.
(2) Stack Context 裏面的信息我們可以 <s:property value="#sss">這樣來訪問
</body>