web---资源的下载及中文乱码问题

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=0;
        byte[] buffer = new byte[1024];
        while ((len=is.read(buffer) )!= -1){
            os.write(buffer,0,len);
        }
    }

}

 

posted @ 2019-04-26 08:34  nlw  阅读(411)  评论(0)  编辑  收藏  举报