Question

我在jsp页面设置receiverid。我正在使用ajax发送textarea值并在相同的方法我得到正常工作的客户端IP。我也想获得在jsp页面中设置的receiverid。但这显示NullPointerException。

在jsp中

<s:set var="receiverid" value="1" scope="request"/>
<form action="" id="post_message_form">
 <s:textarea name="message"></s:textarea>
 <button type="submit" id="submit_status_button">Submit</button>
</form>


 $(document).on('submit', '#post_message_form', function(f) {
        f.preventDefault();
        var formData = $("#post_message_form").serialize();
        console.log(formData);
        $.ajax({
            type: 'POST',
            url: 'PostIt',
            data: formData,
            dataType: "text html",
            success: function(data) {

            }
        })
    });

行动中

public class UserMessageInsert extends ActionSupport implements ModelDriven<PostMessages> {
    PostMessages pm = new PostMessages();
    private long aid;
    public String insert() {
             HttpServletRequest request = ServletActionContext.getRequest();
            String ipAdd = request.getHeader("X-FORWARDED-FOR");
            if (ipAdd == null) {
                ipAdd = request.getRemoteAddr();
                long l=(Long) request.getAttribute("receiverid");//NulllPointer Exception
                System.out.println("Ip is "+ipAdd+" l is "+getAid());
            }
}

Answer 1

我想问题是AJAX调用忽略了你的请求范围属性，因为它创建了一个全新的XMLHttpRequest而不是经典的HttpRequest。

只需将您的属性添加为表单中的隐藏参数，除非您有理由不这样做：

<s:set var="receiverid" value="1" scope="request"/>
<form action="" id="post_message_form">

    <s:hidden value="%{#request.receiverid}" name="receiverid" />

    <s:textarea name="message"></s:textarea>
    <button type="submit" id="submit_status_button">Submit</button>
</form>

然后它会被序列化并提交，您将使用setter或getParameter()而不是getAttribute()来访问它。

无法通过XMLHttpRequest在Action中获取Request-scoped属性

1 个答案: