jsp頁面實現文件的下載

時間 2019-11-13

標籤 jsp 頁面實現文件下載欄目 JSP 简体版

原文原文鏈接

1. 用jsp頁面實現了文件的下載： html

<%@page language="java" contentType="application/x-msdownload"
	pageEncoding="UTF-8"%>

<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>
<%@ page language="java" import="java.io.*"%>
<%@ page language="java" import="java.net.URLEncoder"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>下載文件</title>
</head>
<body>
	<%
	    String docname = request.getParameter("docname");

	    String filedisplay = "";
	    //因爲href連接不能使用中文，這裏根據文件名判斷是否須要改成中文
	    if (docname.equals("txt.txt") || docname.equals("word.doc") || docname.equals("excel.xls"))
	    {

	        filedisplay = "好友信息" + docname.substring(docname.lastIndexOf("."));
	    }
	    else
	    {
	        filedisplay = docname;//"給用戶提供的下載文件名";   
	    }
	    response.reset();//能夠加也能夠不加
	    response.setContentType("application/x-download");
	    String paths = pageContext.getServletContext().getRealPath("/");
	    String realPath = paths + "/download/";
	    String filedownload = realPath + docname;

	    filedisplay = URLEncoder.encode(filedisplay, "UTF-8");
	    response.addHeader("Content-Disposition", "attachment;filename=" + filedisplay);

	    //此處記得清理下。在釋放在jsp中使用的對象時，會調用response.getWriter(),由於這個方法是和response.getOutputStream()相沖突的！
	    out.clear();
	    out = pageContext.pushBody();

	    OutputStream outp = null;
	    FileInputStream in = null;
	    try
	    {
	        outp = response.getOutputStream();
	        in = new FileInputStream(filedownload);

	        byte[] b = new byte[1024];
	        int i = 0;

	        while ((i = in.read(b)) > 0)
	        {
	            outp.write(b, 0, i);
	        }
	        outp.flush();
	    }
	    catch (Exception e)
	    {
	        System.out.println("Download Error!");
	        e.printStackTrace();
	    }
	    finally
	    {
	        if (in != null)
	        {
	            in.close();
	            in = null;
	        }
	        if (outp != null)
	        {
	            outp.close();
	            outp = null;
	        }
	    }
	%>
</body>
</html>

2.添加相關的下載連接，後面跟的參數是下載文件名。例如： java

<a href="../download/down.jsp?docname=soplus.apk" >下載</a>

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