网页实现文件下载_网页设计添加文档下载-优快云博客

本文链接：https://blog.youkuaiyun.com/childlovecsdn/article/details/115488978

本文详细探讨了如何在网页上实现文件的下载功能，包括HTML的`<a>`标签使用，JavaScript的`window.location.href`和`Blob`对象创建下载链接，以及服务器端设置Content-Disposition头来触发浏览器下载。同时，还讨论了安全性问题，如防止恶意文件下载和用户隐私保护措施。

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package servlet.ServletContext;
//实现文件下载
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;

@WebServlet("/ServletContextDemo5")
public class ServletContextDemo5 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //获取请求参数，文件名称
        String filename = request.getParameter("filename");
        // 获取servletContext
        ServletContext servletContext = this.getServletContext();
        // 获取文件的真实路径
        String realPath = servletContext.getRealPath("/img/" + filename);
        // 读文件
        FileInputStream fis = new FileInputStream(realPath);

        String mimeType = servletContext.getMimeType(filename);
        response.setHeader("content-type",mimeType);
        response.setHeader("content-disposition","attachment;filename="+filename);

        //写文件
        ServletOutputStream sos = response.getOutputStream();
        int len = 0;
        byte [] bytes = new byte[ 1028 * 8 ];
        while ( (len = fis.read(bytes)) != -1 ){
            sos.write(bytes,0,len);
        }
        sos.close();


    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request,response);
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>下载文件</title>
</head>
<body>
    <a href="/Servlet2_war_exploded/ServletContextDemo5?filename=1.jpg">图片</a>
    <a href="/Servlet2_war_exploded/img/3.avi">下载文件</a>
</body>
</html>