java 如何将参数传递给servlet
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How to pass parameter to servlet
提问by pypmannetjies
How do I pass a parameter from a page's useBean in JSP to a servlet in Java? I have some data in a form that gets passed no problem with a submit button, but no way to send anything else. Please help? Here is my code:
如何将参数从 JSP 中页面的 useBean 传递到 Java 中的 servlet？我在表单中有一些数据，通过提交按钮没有问题，但无法发送任何其他内容。请帮忙？这是我的代码：
<input name = "deleteGameButton" type = "submit" value = "Delete"
onclick = "submitToServlet('DeleteGameServlet');">
Here is the corresponding javascript:
这是相应的javascript：
function submitToServlet(newAction)
{
document.userGameForm.action = newAction;
}
I'd like the servlet to have access to userBean
我希望 servlet 能够访问 userBean
<jsp:useBean id = "userBean" scope = "session" class = "org.project.User" />
回答by Vladimir Dyuzhev
You kind of mess things here.
你把事情搞得一团糟。
onclick() is Javascript and executed on client side. It has no (direct) way to update session-scoped bean. That bean is left on server-side, and was used when the HTML page was generated. To pass parameters back to servlet you need to use good old form fields, and submit the form.
onclick() 是 Javascript 并在客户端执行。它没有（直接）方法来更新会话范围的 bean。该 bean 留在服务器端，并在生成HTML 页面时使用。要将参数传递回 servlet，您需要使用良好的旧表单字段，然后提交表单。
Add more fields to the form, set their values before submit, then submit.
在表单中添加更多字段，在提交之前设置它们的值，然后提交。
In Servlet call request.getParameter("name");
在 Servlet 中调用 request.getParameter("name");
P.S. To automate this kind of things USE STRUTS. :-) Struts does exactly what you want: before passing the parameters to action, it populates the bean with those parameters. Transparently.
PS 要自动化此类事情，请使用 STRUTS。:-) Struts 完全符合您的要求：在将参数传递给操作之前，它使用这些参数填充 bean。透明地。
回答by mtruesdell
It depends exactly what you are trying to do. The
这完全取决于您要尝试做什么。这
<jsp:useBean id = "userBean" scope = "session" class = "org.project.User" />
<jsp:useBean id = "userBean" scope = "session" class = "org.project.User" />
tag will allow you to use the userBean attribute of the session in your jsp. If there is not a userBean attribute in the session, it will create a new one (using the default constructor for org.project.User) and place it in the session.
标记将允许您在 jsp 中使用会话的 userBean 属性。如果会话中没有 userBean 属性，它将创建一个新属性（使用 org.project.User 的默认构造函数）并将其放置在会话中。
Then, when you get to the servlet, you can retrieve it with:
然后，当您到达 servlet 时，您可以使用以下命令检索它：
User user = (User)request.getSession().getAttribute("userBean");
回答by Naveen kumar HR
getServletConfig().getServletContext().getRequestDispatcher("servlet path & name");
dispatcher.forward (request, response);
