web---资源的下载及中文乱码问题

时间：2024-04-06 12:34:47

1、html网页，超链接交由Servlet处理

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

<h1>实现文件的下载功能</h1>

    <a href="ImgServlet?filename=a.jpg">aa</a><br>

    <a href="ImgServlet?filename=b.jpg">bb </a><br>

    <a href="ImgServlet?filename=图片.png">图片</a><br>

</body>

</body>

</html>

2.web.xml----Servlet的注册

    <servlet>

        <servlet-name>DownLoadImgServlet</servlet-name>。--1

        <servlet-class>nee.DownLoadImgServlet</servlet-class>  --这是我自己的路径

    </servlet>

    <servlet-mapping>

        <servlet-name>DownLoadImgServlet</servlet-name>--2

        <url-pattern>/ImgServlet</url-pattern>--网页的映射，对应html上a的超链接

    </servlet-mapping>
--1 2 处名字必须相同

3.Servlet的实现

package nee;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.URLEncoder;

@WebServlet(name = "DownLoadImgServlet")

public class DownLoadImgServlet extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        this.doGet(request,response);

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        /*

       用字节输出流向文件写资源

       资源需要从输入流中读入

       输入流为图片构成的输入流

         */

        String filename=request.getParameter("filename");

        //解决中文找不到资源路径的问题

        filename = new String(filename.getBytes("ISO-8859-1"),"UTF-8");

        //将文件转化为输入流

        InputStream is=getServletContext().getResourceAsStream("download/"+filename);

        //解决文件名不显示中文的问题

        filename=URLEncoder.encode(filename,"UTF-8");

        //声明这是一个下载的文件

        response.setHeader("Content-Disposition","attachment;filename="+filename);

        OutputStream os=response.getOutputStream();

        int len=;

        byte[] buffer = new byte[];

        while ((len=is.read(buffer) )!= -){

            os.write(buffer,,len);

        }

    }

}

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