問題描述

我正在使用 Struts2 做一個(gè)項(xiàng)目，但在分配集合時(shí)遇到問題.

I am doing a project using Struts2 and I have a problem assigning a set collection.

這是我的操作(我刪除了不相關(guān)的部分)

Here's my Action (I eliminated the irrelevant part)

public class TeamAction extends BaseAction implements ModelDriven<Team>
{
 Team team=new Team();

}

這是我的模型Team(我去掉了不相關(guān)的部分)

Here's my model Team (I eliminated the irrelevant part)

private TeamId id;
private Set students = new HashSet(0);

這是我的 JSP 部分

Here's my JSP part

<input type="text" name=team.student[0].id />

現(xiàn)在的問題是我無法通過 ModelDriven 將正確的值插入到這個(gè) Set 集合中，它會(huì)拋出異常.你能告訴我在 JSP 文件中寫什么，以便我可以在我的模型中向 Set 集合插入一個(gè)值嗎?

Now the problem is I can't insert the right value into this Set collection in by ModelDriven, it will throw a exception. Could you please tell me what to write in JSP file, so I can insert a value to Set collection in my model?

推薦答案

Set 是一個(gè) Collection 并且任何其他集合都可以通過屬性進(jìn)行索引.

Set is a Collection and as any other collection could be indexed by a property.

@Element(value = Student.class)
@Key(value = Integer.class)
@KeyProperty(value = "id") 
@CreateIfNull(value = true)
private Set<Student> students = new HashSet(0);
//getter and setter, also for Student class that should have Integer id.

在 JSP 中

<s:iterator value="students " var="student">
  <s:textfield name="students(%{#student.id}).name" />
</s:iterator>

有關(guān)此的更多信息，請(qǐng)參閱

More about this see

按集合的屬性索引集合.

也有可能獲得一個(gè)獨(dú)特的元素通過傳遞給定屬性的值來收集那個(gè)元素.默認(rèn)情況下，屬性集合的元素在<Class>->conversion.properties 使用KeyProperty_xxx=yyy，其中 xxx 是屬性返回集合的 bean Class 和yyy 是集合元素的屬性我們要索引.

It is also possible to obtain a unique element of a collection by passing the value of a given property of that element. By default, the property of the element of the collection is determined in <Class>->conversion.properties using KeyProperty_xxx=yyy, where xxx is the property of the bean Class that returns the collection and yyy is the property of the collection element that we want to index on.

這篇關(guān)于如何在 Struts 2 中將值插入 Set 集合的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！