Question

这就是我想要做的事情，用户输入一个名字，名称被添加到放置在servlet上的ArrayList中，然后名称应该显示在组合框中，下面就是我所拥有的。它拖曳了错误＆＃34; stray c foreach start tag＆＃34;

的index.jsp

<body>
    <form action="ServletGuardar.do" method="post">
        Name<input type="text" name="name">
        <input type="submit" name="save" value="Save">
    </form>
    <hr>
    <form action="ServletGuardar.do" method="post">
    Names<select name="database1">
        <c:forEach items="${lista}" var="databaseValue">
            <option value="${databaseValue}">
                ${databaseValue}
            </option>
        </c:forEach>
    </select>
    </form>
</body>

SERVLET

ArrayList lista = new ArrayList();
String name = request.getParameter("name");
lista.add(name);

request.setAttribute("lista", "lista");

request.getRequestDispatcher("index.jsp").forward(request, response);
}

Answer 1

我测试了您的代码并通过更改以下内容使其正常工作

如果您的jsp没有引用标记库，则添加它
在服务器端，您没有添加ArrayList对象来请求而不是你把它添加为String作为已经提到的另一个答案。
同时检查从第一个表单提交名称的时间，打印和如果在服务器端获得名称值，请检查日志。

<强>的index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Index</title>
</head>
<body>
    <form action="./ServletGuardar.do" method="post">
        Name<input type="text" name="name">
        <input type="submit" name="save" value="Save">
    </form>
    <hr>
    <form action="/ServletGuardar.do" method="post">

    Names<select name="database1">
        <c:forEach items="${list}" var="databaseValue">
            <option value="${databaseValue}">
                ${databaseValue}
            </option>
        </c:forEach>
    </select>

    </form>
</body>
</html>

Servlet的doGet方法

protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // TODO Auto-generated method stub

        ArrayList<String> list = new ArrayList<String>();

        String name = request.getParameter("name");
        System.out.println("name=" + name);

        list.add(name);

        request.setAttribute("list", list);

        request.getRequestDispatcher("index.jsp").forward(request, response);

        // response.getWriter().append("name="+name+".Served at:
        // ").append(request.getContextPath());
    }

<强>的web.xml

  <servlet>
        <servlet-name>HelloServlet</servlet-name>
        <servlet-class>com.ServletGuardar</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>HelloServlet</servlet-name>
        <url-pattern>/ServletGuardar.do</url-pattern>
    </servlet-mapping>

由用户填充到ComboBox（选择JPS）填充的ArrayList

1 个答案: