java 将数组列表添加到会话
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Adding an array list to a session
提问by Katana24
Im trying to store an array list in session like so:
我试图在会话中存储一个数组列表，如下所示：
private Map session = ActionContext.getContext().getSession();
The array list looks like this:
数组列表如下所示：
private ArrayList<Integer> numbersEntered = new ArrayList<Integer>();
If the array list doesn't already exist in session it is added but Im having problems adding new data to the array list and updating the session with that data. So - my problem is how do I get what is already in session, store it temporarily, add to it based on the user input and re-add to the session?
如果会话中不存在数组列表，则会添加它，但我在将新数据添加到数组列表并使用该数据更新会话时遇到问题。所以 - 我的问题是如何获取会话中已经存在的内容，临时存储它，根据用户输入添加到它并重新添加到会话中？
if ( !session.containsKey(arrayListID) )
{
// Place the number the user entered into the session
session.put(arrayListID, numbersEntered);
} else {
// Retrieve session data
}
I retrieve what was stored initially and placed it in a string but because it was anm array list it was stored like: [12]. I don't want to have to convert it or split the string...Let me know if you need more info here.
我检索了最初存储的内容并将其放在一个字符串中，但因为它是一个数组列表，所以它的存储方式如下：[12]。我不想转换它或拆分字符串...如果您需要更多信息，请告诉我。
Cheers
干杯
回答by Giordano Maestro
if ( !session.containsKey(arrayListID) )
{
// Place the number the user entered into the session
session.put(arrayListID, numbersEntered);
} else {
ArrayList<Integer> list = (ArrayList<Integer>) session.get(arrayListID);
list.add( 1 /* what you want */);
// Retrieve session data
}
