javascript 将会话变量数据从jsp传递到java
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Passing session variable data from jsp to java
提问by Seeya K
I have created session variables since I want to transfer data from one JSP to another.
Each of my JSPs is a tab.
I transfer data given from the user from one JSP to another using the request body. I have <form>..><button type = "submit"/> </form>in the last JSP from where I submit the data and use it in a Java class.
我创建了会话变量，因为我想将数据从一个 JSP 传输到另一个。我的每个 JSP 都是一个选项卡。我使用请求正文将用户提供的数据从一个 JSP 传输到另一个 JSP。我<form>..><button type = "submit"/> </form>在最后一个 JSP 中提交数据并在 Java 类中使用它。
When I try to access the session data from all the JSP pages, it returns a null value for all the data.
当我尝试从所有 JSP 页面访问会话数据时，它为所有数据返回一个空值。
How should I transfer all the session data from all the JSPs to a Java class? Please note that each JSP is a tab, and I submit data from the last JSP.
我应该如何将所有 JSP 中的所有会话数据传输到 Java 类？请注意，每个 JSP 都是一个选项卡，我从最后一个 JSP 提交数据。
Code:
代码：
<%
String joindate = request.getParameter( "joindate" );
session.setAttribute("joindate",joindate);
String birthdate = request.getParameter( "birthdate" );
session.setAttribute("birthdate",birthdate);
%>
回答by zz3599
In general, just try to avoid scriptlets. You should definitely do what Makoto recommended: use a MVC pattern by having your JSPs submit their data to a servlet, which does the heavy duty lifting.
一般来说，尽量避免使用 scriptlet。您绝对应该按照 Makoto 的建议去做：使用 MVC 模式，让您的 JSP 将它们的数据提交给一个 servlet，servlet 完成繁重的工作。
Whenever you have a form in a JSP, consider using
每当您在 JSP 中有表单时，请考虑使用
<form action="servletpattern?action=add_date" method="post">
<form action="servletpattern?action=add_date" method="post">
Then in the servlet:
然后在 servlet 中：
HttpSession session = request.getSession();
String action = request.getParameter("action");
if(action.equals("add_date")){
String joindate = request.getParameter( "joindate" );
session.setAttribute("joindate",joindate);
String birthdate = request.getParameter( "birthdate" );
session.setAttribute("birthdate",birthdate);
} else if(action.equals("someotheraction"){
//do something else
}
In the JSP you should again not use scriptlets but instead access the session variables through EL :
在 JSP 中，您不应该再次使用 scriptlet，而是通过 EL 访问会话变量：
join date: ${joindate}, birth date: ${birthdate}
