Question

我有多个表单输入，我想从文本字段中获取所有值。

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<!-- Bootstrap Core CSS -->
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<style type="text/css">
* {
  .border-radius(0) !important;
}

#field {
    margin-bottom:5px;
}
</style>
</head>
<body>
<div class="container">
	<div class="row">
		<input type="hidden" name="count" value="1" />
        <div class="control-group" id="fields">
            <label class="control-label" for="field1">Nice Multiple Form Fields</label>
            <div class="controls" id="profs"> 
                <form class="input-append" method='post' action='AddReqPo'>
                    <div id="field"><input autocomplete="off" class="input" id="field1" name="a" type="text" placeholder="Type something" data-items="8"/><button id="b1" class="add-more" type="button">+</button></div>
                <input type='submit'>
                </form>
            <br>
            <small>Press + to add another form field :)</small>
            </div>
        </div>
	</div>
</div>
</body>
<script type="text/javascript">
$(document).ready(function(){
    var next = 1;
    $(".add-more").click(function(e){
        e.preventDefault();
        var addto = "#field" + next;
        var addRemove = "#field" + (next);
        next = next + 1;
        var newIn = '<input autocomplete="off" class="input" id="field' + next + '" name="a' + next + '" type="text">';
        var newInput = $(newIn);
        var removeBtn = '<button id="remove' + (next - 1) + '" class="btn-danger remove-me" >-</button></div><div id="field">';
        var removeButton = $(removeBtn);
        $(addto).after(newInput);
        $(addRemove).after(removeButton);
        $("#field" + next).attr('data-source',$(addto).attr('data-source'));
        $("#count").val(next);  
        
            $('.remove-me').click(function(e){
                e.preventDefault();
                var fieldNum = this.id.charAt(this.id.length-1);
                var fieldID = "#field" + fieldNum;
                $(this).remove();
                $(fieldID).remove();
            });
    }); 
});
</script>
</html>

这是用于从该表单获取值的操作（AddReqPo.java）。值分配给数组。输入的名称相同。

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    Database db = (Database) getServletContext().getAttribute("db");
    String[] a=request.getParameterValues("a");
        System.out.println(a[0]);
        System.out.println(a[1]);
        System.out.println(a[2]);
    response.sendRedirect("index.jsp");
}

但java.lang.NullPointerException

System.out.println(a[0]);

我该如何解决？

多个表单无法读取输入名称（NullPointerExeption）

0 个答案: