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案例–文件下载–分析

案例–文件下载–代码实现

package cn.itcast.web.download; import javax.servlet.ServletContext; import javax.servlet.ServletException; 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.FileOutputStream; import java.io.IOException; @WebServlet("/DownloadServlet_Demo1") public class DownloadServlet_Demo1 extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String filename = request.getParameter("filename"); ServletContext servletContext = this.getServletContext(); String mimeType = servletContext.getMimeType(filename); response.setHeader("content-type",mimeType); response.setHeader("content-disposition","attachment;filename="+filename); String realPath = servletContext.getRealPath("/img/" + filename); FileInputStream fileInputStream = new FileInputStream(realPath); ServletOutputStream outputStream = response.getOutputStream(); byte[] bytes = new byte[1024 * 5]; int len=0; while ((len=fileInputStream.read(bytes))!=-1){ outputStream.write(bytes,0,len); } fileInputStream.close(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } } <a href="/DownloadServlet_Demo1?filename=a.png">云同桌</a>

案例–文件下载–中文文件名问题（未成功）

package cn.itcast.web.utils; import sun.misc.BASE64Encoder; import java.io.UnsupportedEncodingException; import java.net.URLEncoder; public class DownLoadUtils { public static String getFileName(String agent, String filename) throws UnsupportedEncodingException { if (agent.contains("MSIE")) { // IE浏览器 filename = URLEncoder.encode(filename, "utf-8"); filename = filename.replace("+", " "); } else if (agent.contains("Firefox")) { // 火狐浏览器 BASE64Encoder base64Encoder = new BASE64Encoder(); filename = "=?utf-8?B?" + base64Encoder.encode(filename.getBytes("utf-8")) + "?="; } else { // 其它浏览器 filename = URLEncoder.encode(filename, "utf-8"); } return filename; } }