java - 在 中使用 几次

Question

我是 Spring 的新手，我正在尝试使用 Spring MVC + JSP + JSTL。我的目标是制作包含用户列表的 JSP，并允许单独编辑每个用户。所以我想我应该单独使用 <form>标记并分隔 <sumbit>列表中每个用户的按钮和我的 JSP 如下所示:

<c:forEach items="${userList}" var="currentUser" varStatus="index">
        <form:form method="post" action = "edit" commandName="userList[${index}]">
        <tr>
            <td><form:input path = "userList[${index}].login" value = "${currentUser.login}" /></td>
            <td><form:input path = "userList[${index}].password" value = "${currentUser.password}" /></td>
            <td><form:input path = "userList[${index}].smtpServer" value = "${currentUser.smtpServer}" /></td>
            <td><form:input path = "userList[${index}].popServer" value = "${currentUser.popServer}" /></td>
                <form:hidden path="userList[${index}].id" value=""/>
            <td>
                <a href="delete/${user.id}"><spring:message code="label.delete" /></a>
            </td>
        </tr>
           <input type="submit" value = "edit"> 
        </form:form>
    </c:forEach>

想法是有机会通过按“编辑”按钮分别编辑每个用户。当然这段代码不起作用。它给了我一个异常(exception):

java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'userList[javax' available as request attribute

我对 Spring 和 web 编程完全是个菜鸟。我将不胜感激。

Answer 1

您对 ${index} 的使用不是您想象的那样。要获取当前项目的索引，您必须将“.index”附加到您的 varStatus 变量...在您的情况下它将是 ${index.index}。为清楚起见，请考虑将您的 varStatus 命名为 index 以外的名称...

<c:forEach items="${userList}" var="currentUser" varStatus="uStatus">
    <form:form method="post" action = "edit" commandName="userList">
    <tr>
        <td><form:input path = "userList[${uStatus.index}].login" value = "${currentUser.login}" /></td>
        <td><form:input path = "userList[${uStatus.index}].password" value = "${currentUser.password}" /></td>
        <td><form:input path = "userList[${uStatus.index}].smtpServer" value = "${currentUser.smtpServer}" /></td>
        <td><form:input path = "userList[${uStatus.index}].popServer" value = "${currentUser.popServer}" /></td>
            <form:hidden path="userList[${uStatus.index}].id" value=""/>
        <td>
            <a href="delete/${currentUser.id}"><spring:message code="label.delete" /></a>
        </td>
    </tr>
       <input type="submit" value = "edit"> 
    </form:form>
</c:forEach>

请记住，为每个用户使用不同的表单是没有意义的……但是假设您想一次编辑任何/所有用户……

<form:form method="post" action = "edit" commandName="userList">
    <c:forEach items="${userList}" var="currentUser" varStatus="uStatus">

    <tr>
        <td><form:input path = "userList[${uStatus.index}].login" value = "${currentUser.login}" /></td>
        <td><form:input path = "userList[${uStatus.index}].password" value = "${currentUser.password}" /></td>
        <td><form:input path = "userList[${uStatus.index}].smtpServer" value = "${currentUser.smtpServer}" /></td>
        <td><form:input path = "userList[${uStatus.index}].popServer" value = "${currentUser.popServer}" /></td>
            <form:hidden path="userList[${uStatus.index}].id" value=""/>
        <td>
            <a href="delete/${currentUser.id}"><spring:message code="label.delete" /></a>
        </td>
    </tr>

    </c:forEach>
    <input type="submit" value = "edit"> 
</form:form>