将参数从jsp传递到servlet [英] pass parameter from jsp to servlet

问题描述

如何使用不属于session的form形式的表单将参数从jsp传递到servlet.我认为代码可能看起来像下面的示例，但对我不起作用.plz帮助我.

how to pass a parameter from jsp to servlet using form which is not belong to any field of form without using session.i think code may be look like below example but doesn't work for me.plz help me.

在index.jsp中:-

in index.jsp:-

<form method="Post" action="servlet">
        <input type="text" name="username">
        <input type="password" name="password">
          <% 
              int z=1;
              request.setAttribute("product_no", z);%>
        <input type='submit' />
</form>

在servlet.java中:-

in servlet.java:-

 int x=Integer.parseInt(request.getAttribute("product_no").toString());

推荐答案

您的表单需要提交，例如有一个提交按钮.并且您需要将参数作为输入.在窗体内调用request.setAttribute不会执行任何操作.设置请求属性的目的是要在使用分派器转发请求时使用，而不是在使用表单时.

Your form needs to be submitted, e.g. have a submit button. And you need to have your parameter as an input. Calling request.setAttribute inside the form doesn't do anything. Setting a request attribute is for when you are going to use a dispatcher to forward the request, not when you are using a form.

<% int z=1; %>
<form method="Post" action="servlet">
        <input type="text" name="username" />
        <input type="password" name="password" />
        <input type="hidden" name="product_no" value="<%=z%>" />
        <input type='submit' />
</form>

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