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Struts学习笔记_OGNL

1,使用域模型时,只有传参user.age=8,才会new一个user对象,当然也可以再action中手动new一个user对象。所以初始化域模型时,可以自己构造,也可以传值,但这时必须有空的构造方法。

2.当用chain跳转到另一个action时,值栈中会有两个action对象

strust.xml

<struts>    <constant name="struts.enable.DynamicMethodInvocation" value="false" />    <constant name="struts.devMode" value="true" />    <constant name="struts.ognl.allowStaticMethodAccess" value="true"></constant>//允许调用静态方法    <include file="/com/bjsxt/struts2/ognl/ognl.xml"/>    <!--  <include file="/testognl/testognl.xml"/>--></struts>

ognl.xml

<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>//调用这个时值栈中会有两个action对象        </action>    </package></struts>
OgnlAction .java
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;    }}
ognl.jsp
<body>    <ol>        <li>访问值栈中的action的普通属性: username = <s:property value="username"/> </li>        <li>访问值栈中对象的普通属性(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>访问值栈中对象的普通属性(get set方法): <s:property value="cat.friend.name"/></li>        <li>访问值栈中对象的普通方法:<s:property value="password.length()"/></li>        <li>访问值栈中对象的普通方法:<s:property value="cat.miaomiao()" /></li>        <li>访问值栈中action的普通方法:<s:property value="m()" /></li>        <hr />        <li>访问静态方法:<s:property value="@com.bjsxt.struts2.ognl.S@s()"/></li>        <li>访问静态属性:<s:property value="@com.bjsxt.struts2.ognl.S@STR"/></li>        <li>访问Math类的静态方法:<s:property value="@@max(2,3)" /></li>        <hr />        <li>访问普通类的构造方法:<s:property value="new com.bjsxt.struts2.ognl.User(8)"/></li>        <hr />        <li>访问List:<s:property value="users"/></li>        <li>访问List中某个元素:<s:property value="users[1]"/></li>        <li>访问List中元素某个属性的集合:<s:property value="users.{age}"/></li>        <li>访问List中元素某个属性的集合中的特定值:<s:property value="users.{age}[0]"/> | <s:property value="users[0].age"/></li>        <li>访问Set:<s:property value="dogs"/></li>        <li>访问Set中某个元素:<s:property value="dogs[1]"/></li>        <li>访问Map:<s:property value="dogMap"/></li>        <li>访问Map中某个元素:<s:property value="dogMap.dog101"/> | <s:property value="dogMap[‘dog101‘]"/> | <s:property value="dogMap[\"dog101\"]"/></li>        <li>访问Map中所有的key:<s:property value="dogMap.keys"/></li>        <li>访问Map中所有的value:<s:property value="dogMap.values"/></li>        <li>访问容器的大小:<s:property value="dogMap.size()"/> | <s:property value="users.size"/> </li>        <hr />        <li>投影(过滤):<s:property value="users.{?#this.age==1}[0]"/></li>        <li>投影:<s:property value="users.{^#this.age>1}.{age}"/></li>//^指的是开头        <li>投影:<s:property value="users.{$#this.age>1}.{age}"/></li>//$指的是结尾        <li>投影:<s:property value="users.{$#this.age>1}.{age} == null"/></li>//返回FALSE        <hr />        <li>[]:<s:property value="[0].username"/></li>//[0]指的是从0开始的所有对象            </ol>        <s:debug></s:debug></body>

 

Struts学习笔记_OGNL