Said another way, let's say I have a value stack that consists of a
model and an action as follows:
[ model, action ]
here's how the following ognl would resolve:
[0] - a CompoundRoot object that contains our stack, [model, action]
[1] - another CompoundRoot that contains only [action]
[0].toString() - calls toString() on the first object in the value stack (excluding the CompoundRoot) that supports the toString() method
[1].foo - call getFoo() on the first object in the value stack starting from [OS:action] and excluding the CompoundRoot that supports a getFoo() method
以上是webwork文档中谈到Value Stack部分.看了有些晦涩,我试验了下,与大家分享.(没看源代码)
Action:
public class HomeAction implements Action 
{
private String name= "propertyOfAction";
private Person person=null;
private Collection collection = new ArrayList();
public String execute() throws Exception {
collection.add(new Person("zkj"));
collection.add(new Person("yql"));
collection.add(person);
return SUCCESS;
}
public String getName() {
return name;
}
public Person getPerson() {
return person;
}
public Collection getCollection() {
return collection;
}
public void setPerson(Person person) {
this.person = person;
}
}在jsp页面中:
如果我们直接
<ww:property value="[0]"/> 输出
com.founder.HomeAction@e3ffdf,com.opensymphony.xwork.DefaultTextProvider@d402dd]
<ww:property value="[1]"/> 输出[com.opensymphony.xwork.DefaultTextProvider@d402dd]
一般我们在没有循环的情况下不用[0] [1] 可以直接访问
<ww:property value="name"/>输出 propertyOfAction
那么[0] [1] 有什么用呢,在循环中就体现出来了.
<ww:iterator value="collection" status="person">
<ww:if test="#person.first == true">
[0] :<ww:property value="[0]"/></br>
[1] :<ww:property value="[1]"/></br>
[2] :<ww:property value="[2]"/></br>
</ww:if>
</ww:iterator>
[1] :[com.founder.HomeAction@e3ffdf, com.opensymphony.xwork.DefaultTextProvider@d402dd]
[2] :[com.opensymphony.xwork.DefaultTextProvider@d402dd]
输出以上代码,说明在一层循环中我们要访问[1]表示action对象.和没有循环的[0]对应.
总结:
假如你用webworkNOUI标签,对于Value Stack,一般你不要考虑[1] [0]之类的.记住一点
如果在循环中action的collection属性时体内,用[1]可以访问action对象和对应的属性.
对于多层循环或复杂用法,我只能告诉你,你的设计有问题?重构Model代码吧.