jsp用流實現下載功能

最後更新：2017-01-13 來源：互聯網

上載者：User

創建阿里雲帳戶，並獲得超過 40 款產品的免費試用版；而企業帳戶則可以享有總值 $1200 的免費試用版。立即註冊！

我在做jsp的下載功能時遇到了問題，不知道什麼原因：

首先我做了一個jsp檔案：filedown.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>你好</title>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    </head>
    <body>
        <a href="DownloadServlet">download</a>
    </body>
</html>

然後我做了一個servlet：DownloadServlet.java

import java.io.BufferedInputStream;
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.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class DownloadServlet extends HttpServlet {

    /**
     * The doGet method of the servlet.

     *
     * This method is called when a form has its tag value method equals to get.
     *
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {


        String filePath ="D:/apple/2007.doc";
        String fileType ="doc";


        File file = new File(filePath);
        response.setCharacterEncoding("gb2312");
        response.setContentType(fileType);
        response.setHeader("Content-Disposition", "attachment; filename=" + new String(file.getName().getBytes("gb2312"),"iso8859-1"));

        System.out.println(new String(file.getName().getBytes("gb2312"),"gb2312"));

        OutputStream output = null;
        FileInputStream fis = null;
        try
        {
            output  = response.getOutputStream();
            fis = new FileInputStream(file);

            byte[] b = new byte[1024];
            int i = 0;
            System.out.println("++++++++++++++++++++++++++++");
            while((i = fis.read(b))!=-1)
            {

                output.write(b, 0, i);
            }
            output.write(b, 0, b.length);
            System.out.println("++++++++++++++++++++++++++++");
            output.flush();
            response.flushBuffer();
        }
        catch(Exception e)
        {
            System.out.println("Error!");
            e.printStackTrace();
        }
        finally
        {
            if(fis != null)
            {
                fis.close();
                fis = null;
            }
            if(output != null)
            {
                output.close();
                output = null;
            }
        }

    }

    /**
     * The doPost method of the servlet.

     *
     * This method is called when a form has its tag value method equals to post.
     *
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        doGet(request,response);
    }
}

上面的servlet是我在網上找到的原始碼，我加了output.write(b, 0, b.length);這句話。（可是我加沒加效果都一樣，都是錯的）

我的準備工作是：D:/apple/2007.doc這個檔案是肯定存在的。

本文章原先以中文撰寫並發佈於 aliyun.com，亦設英文版本，僅作資訊用途。本網站不對文章的準確性，完整性或可靠性或其任何翻譯作出任何明示或暗示的陳述或保證。如對該文章有任何疑慮或投訴，請傳送電郵至 info-contact@alibabacloud.com 並提供相關疑慮或投訴的詳細說明。職員會於 5 個工作天內與您聯絡，一經驗證之後，即會刪除該侵權內容。

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

Sales Support

1 on 1 presale consultation

Chat Contact Sales
After-Sales Support

24/7 Technical Support 6 Free Tickets per Quarter Faster Response

Open a Ticket
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

Learn More