JavaWeb案例: 文件下载 基于tomcat8 默认编码为UTF-8
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1 package cn.itcast.download; 2 3 import javax.servlet.ServletException; 4 import javax.servlet.ServletOutputStream; 5 import javax.servlet.annotation.WebServlet; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 import java.io.FileInputStream; 10 import java.io.IOException; 11 12 @WebServlet("/001") 13 public class DownloadServlet extends HttpServlet { 14 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 15 //获取资源名 16 String filename = request.getParameter("filename"); 17 //获取资源对应输入流 18 FileInputStream fis = new FileInputStream(request.getServletContext().getRealPath("/download/" + filename)); 19 //告知类型 20 response.setContentType(request.getServletContext().getMimeType(filename)); 21 //告知下载 22 response.setHeader("content-disposition", "attachment;filename=" + filename); 23 //获取响应输出流 24 ServletOutputStream sos = response.getOutputStream(); 25 //写数据 26 byte[] bys = new byte[1024 * 8]; 27 int len; 28 while((len = fis.read(bys)) != -1){ 29 sos.write(bys, 0, len); 30 } 31 //释放资源 32 fis.close(); 33 } 34 35 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 36 doPost(request, response); 37 } 38 }
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1 package cn.itcast.download; 2 3 import javax.servlet.ServletException; 4 import javax.servlet.ServletOutputStream; 5 import javax.servlet.annotation.WebServlet; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 import java.io.FileInputStream; 10 import java.io.IOException; 11 import java.net.URLEncoder; 12 import java.util.Base64; 13 14 @WebServlet("/download") 15 public class DownloadServlet2 extends HttpServlet { 16 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 17 //获取资源名 18 String filename = request.getParameter("filename"); 19 //获取资源对应输入流 20 FileInputStream fis = new FileInputStream(request.getServletContext().getRealPath("/download/" + filename)); 21 //告知类型 22 response.setContentType(request.getServletContext().getMimeType(filename)); 23 //告知下载 24 //处理响应头乱码,浏览器兼容性问题 25 String agent = request.getHeader("user-agent"); 26 String fileNameEnc = null; 27 if(agent.contains("MSIE")){ 28 fileNameEnc = URLEncoder.encode(filename,"UTF-8").replace("+", " "); 29 }else if(agent.contains("Firefox")){ 30 fileNameEnc = "=?utf-8?B?" 31 + Base64.getEncoder().encodeToString(filename.getBytes("UTF-8")) 32 + "?="; 33 }else{ 34 fileNameEnc = URLEncoder.encode(filename,"UTF-8"); 35 } 36 response.setHeader("content-disposition", "attachment;filename=" + fileNameEnc); 37 //获取响应输出流 38 ServletOutputStream sos = response.getOutputStream(); 39 //写数据 40 byte[] bys = new byte[1024 * 8]; 41 int len; 42 while((len = fis.read(bys)) != -1){ 43 sos.write(bys, 0, len); 44 } 45 //释放资源 46 fis.close(); 47 } 48 49 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 50 doPost(request, response); 51 } 52 }