程序行为不同，当提交和使用的jQuery $后

我会通过在当按钮被点击PDF文件应该得到下载非常混乱的局面，我的设计和要求是一样的东西如下：

点击有两个按钮save和按钮
显示确认框open
如果保存被选中，那么PDF应该被保存在本地计算机上。

第三点是我所面临的问题，因为在没有确认框以下形式使用submit button（没有确认框）时提交文件，然后是越来越下载。下面是代码：

<button type="submit" id="Export">xxx_tutorial</button>

但是，当只有一个button与onclick事件确认框写在Jquery，我已经使用$Post提交数据的servlet在数据传递到servlet中，但文件没有得到下载。现在

我的问题是：

是通过$post传递数据不等同于submit与传递数据一起Servlet时点击提交按钮会发生什么。
当数据被传递给servlet时，为什么文件没有被下载到相同的代码正在使用提交按钮时没有确认框。

真的我迷路了，无法理解确切的。请专家帮忙，我很乐意提供建议。

下面是代码：

JSP：

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" 
    pageEncoding="ISO-8859-1"%> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<head> 
<link rel="stylesheet" href="https://code.jquery.com/ui/1.11.2/themes/redmond/jquery-ui.css"> 
<script src="https://code.jquery.com/jquery-1.11.2.js"></script> 
<script src="https://code.jquery.com/ui/1.11.2/jquery-ui.js"></script> 
<!-- User Defined Js file --> 
<script type="text/javascript"> 

$(document).ready(function(){ 
      $('#Export').click(function(event) { 
      event.preventDefault(); 
     var currentForm = $(this).closest('form'); 

     var dynamicDialog = $('<div id="conformBox">'+ 
     '<span style="float:left; margin:0 7px 20px 0;">'+ 
     '</span>Open or save the document</div>'); 

     dynamicDialog.dialog({ 
       title : "Open/Save Dialog", 
       closeOnEscape: true, 
       modal : true, 

       buttons : 
         [{ 
           text : "Export", 
           click : function() { 

            $(this).dialog("close"); 
            var data = "xxx_tutorial"; 
            $.post('button', {param: data}, function(param){ 


      }); 
           } 
         }, 
         { 
           text : "Open", 
           click : function() { 
             $(this).dialog("close"); 
           } 
         }] 
     }); 
     return false; 
    }); 

}); 
</script> 
</head> 
<body> 
     <button type="button" id="Export">xxx_tutorial</button> 

</body> 
</html>

的Servlet：

package com.testcase.testing; 

import java.io.File; 
import java.io.FileInputStream; 
import java.io.IOException; 
import java.io.OutputStream; 
import java.io.PrintWriter; 

import javax.servlet.ServletException; 
import javax.servlet.annotation.WebServlet; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

/** 
* Servlet implementation class button 
*/ 
@WebServlet("/button") 
public class button extends HttpServlet { 
    private static final long serialVersionUID = 1L; 

    /** 
    * @see HttpServlet#HttpServlet() 
    */ 
    public button() { 
     super(); 
     // TODO Auto-generated constructor stub 
    } 

    /** 
    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) 
    */ 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
     // TODO Auto-generated method stub 
     doPost(request, response); 
     } 

    /** 
    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) 
    */ 
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
     // TODO Auto-generated method stub 

     response.getWriter().append(request.getParameter("param")); 
     performTask(request,response); 
    } 

    private void performTask(HttpServletRequest request, HttpServletResponse response) throws ServletException, 
    IOException { 

     String pdfFileName=""; 

     if(request.getParameter("param")==null){ 

    } 
    else if(request.getParameter("param").matches("sap_webi_tutorial")){ 
     System.out.println("in create pdf file name part"); 
     pdfFileName = "/"+request.getParameter("param")+".pdf"; 
    } 
     else{ 

     } 

String contextPath = getServletContext().getRealPath(File.separator); 
File pdfFile = new File(contextPath + "/xxx_tutorial.pdf"); 
response.setContentType("application/pdf"); 
response.addHeader("Content-Disposition", "attachment; filename=" + "/xxx_tutorial.pdf"); 
response.setContentLength((int) pdfFile.length()); 

FileInputStream fileInputStream = new FileInputStream(pdfFile); 
PrintWriter responseOutputStream = response.getWriter(); 
int bytes; 
    while ((bytes = fileInputStream.read()) != -1) { 
    responseOutputStream.write(bytes); 
} 
fileInputStream.close(); 
responseOutputStream.flush(); 
responseOutputStream.close(); 
    } 
}

来源

2017-05-27 Siva