Javascript 表单提交后返回结果

我需要一个快速的帮助

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我希望用户可以上传一个csv文件。然后我对后面的文件进行一些解析和有意义的操作。最后，将结果显示回用户。当他们上传文件时，我想检查文件大小是否使用按钮而不是提交。这是因为提交类型输入正在提交表单，但您也可以使用ajax发送请求。这就是两个请求的原因。

好的，让我试试。谢谢你的回复。你的意思是type=“button”不是type=“submit”。。。现在我明白了。。。Thankshange type=“submit”to type=“button”将获得json返回

<form action="/Project/CSVUpload" method="post" enctype="multipart/form-data">
<br />
<input id="uploadfilebutton" type="file" name="file" class="tss-btn tss-btn-blue" accept=".csv" required />
<br />
<input id="processfilebutton" type="submit" value="Process File" class="tss-btn tss-btn-blue" />
</form>

function process()
{
$.ajax({
    url:"/Project/CSVUpload",
    type:'POST',
    contentType: 'application/json',
    dataType: 'json',
    success:function(soapContents){

        if (soapContents.haserrors)
        {
            BootstrapDialog.show({
                title: 'Process File Failed',
                message: soapContents.returnmessage,
                buttons: [ {
                    label: 'Ok',
                    action: function(dialogItself){

                        dialogItself.close();
                    }
                }]
            }); 
        }

    }
});
}

@WebServlet("/CSVUploads")
public class CSVUpload extends HttpServlet 
{

public void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, java.io.IOException 
{
boolean hasErrors = false;
if (CSVUpload success) // assume we get the info from CSVUpload class
{
    hasErrors = true;
}
if (hasErrors)
    {
        log.error("CSVUpload: "+returnMessage);

        // Setup JSON response. 
        JsonObjectBuilder jsonObjectBuilder = Json.createObjectBuilder();
        jsonObjectBuilder.add("haserrors", hasErrors);
        jsonObjectBuilder.add("returnmessage", returnMessage);
        JsonObject jsonObject = jsonObjectBuilder.build();

        // Write the JSON out as a response. 
        PrintWriter printWriter = response.getWriter();
        printWriter.print(jsonObject);
        printWriter.flush();
    }
}