Java 如何使用会话将ArrayList从一个jsp传递到另一个jsp
我试图将ArrayList从handle.jsp传递到main.jsp,但它不允许我这样做。它一直在说“类型不匹配:无法从Object转换为ArrayList” main.jsp:Java 如何使用会话将ArrayList从一个jsp传递到另一个jsp,java,jsp,session,arraylist,Java,Jsp,Session,Arraylist,我试图将ArrayList从handle.jsp传递到main.jsp,但它不允许我这样做。它一直在说“类型不匹配:无法从Object转换为ArrayList” main.jsp: <%@ page import="java.util.ArrayList" %> <html> <body> <h1>Hobby Manager</h1> <% ArrayList<String> hobbies
<%@ page import="java.util.ArrayList" %>
<html>
<body>
<h1>Hobby Manager</h1>
<%
ArrayList<String> hobbies = session.getAttribute("hobbies");
out.println(hobbies.size());
out.println(session.getAttribute("hobbies"));
%>
<h2>Add new hobby!</h2>
<FORM action="handleAddHobby.jsp" method="get">
What new hobby are you wishing to add? <INPUT TYPE=text name=hobbyName /> <br/>
<INPUT TYPE=submit name=addHobby value="Add Hobby" />
</FORM>
</body>
</html>
爱好经理
添加新的爱好!
你想增加什么新爱好
handle.jsp:
<%@ page import="java.util.ArrayList" %>
<html>
<body>
<%
ArrayList<String> hobbies = new ArrayList<String>();
String hobbyName = request.getParameter("hobbyName");
if(hobbyName == null){
out.println("Please enter a hobby before clicking add! Dummy.<br/>");
}
else{
hobbies.add(hobbyName);
for(int index = 0; index < hobbies.size(); index ++){
out.println(hobbies.get(index) + "<br/>");
}
session.setAttribute("hobbies", hobbies);
}
%>
</body>
</html>
我曾尝试将其作为字符串对象传递,并单独作为对象传递,但似乎没有任何效果。问题就在这里
ArrayList<String> hobbies = session.getAttribute("hobbies");
ArrayList嗜好=session.getAttribute(“嗜好”);
尝试将其类型转换为getAttribute始终返回对象
ArrayList<String> hobbies = (ArrayList<String>)session.getAttribute("hobbies");
ArrayList嗜好=(ArrayList)session.getAttribute(“嗜好”);
问题就在这里
ArrayList<String> hobbies = session.getAttribute("hobbies");
ArrayList嗜好=session.getAttribute(“嗜好”);
尝试将其类型转换为getAttribute始终返回对象
ArrayList<String> hobbies = (ArrayList<String>)session.getAttribute("hobbies");
ArrayList嗜好=(ArrayList)session.getAttribute(“嗜好”);
你是如何从句柄进入主页的?你是如何从句柄进入主页的?