window.location.href =“后臺方法地址"。

String filePath = this.getClass().getClassLoader().getResource("").toURI().getPath()     + "/exportPdf.pdf"; //文件在項目中的路徑  File outfile = new File(filePath);  String filename = outfile.getName();// 獲取文件名稱  InputStream fis = new BufferedInputStream(new FileInputStream(     filePath));  byte[] buffer = new byte[fis.available()];   fis.read(buffer); //讀取文件流  fis.close();  response.reset(); //重置結(jié)果集  response.addHeader("Content-Disposition", "attachment;filename="    + new String(filename.replaceAll(" ", "").getBytes("utf-8"),    "iso8859-1")); //返回頭 文件名  response.addHeader("Content-Length", "" + outfile.length()); //返回頭 文件大小  response.setContentType("application/octet-stream"); //設(shè)置數(shù)據(jù)種類  //獲取返回體輸出權(quán)  OutputStream os = new BufferedOutputStream(response.getOutputStream());   os.write(buffer); // 輸出文件  os.flush();  os.close();

package cn.itcast.day06.web.servlet; import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.net.URLEncoder; import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; public class DownloadServlet extends HttpServlet {  public void doGet(HttpServletRequest request, HttpServletResponse response)  throws ServletException, IOException {  // 實現(xiàn)防盜鏈功能 // 獲得 referer 頭 用于說明來訪者來自哪里 String referer = request.getHeader("referer"); if(referer==null || !referer.startsWith("http://localhost")) {  // 是盜鏈者  response.sendRedirect("/day06/index.jsp");  return ; }   // 解決response中文亂碼問題 response.setContentType("text/html;charset=utf-8"); // 設(shè)置消息體的編碼   // 通過 http 協(xié)議 發(fā)送的http響應(yīng)消息頭 不能出現(xiàn)中文 中文必須要經(jīng)過url編碼 String filename = URLEncoder.encode("美女.jpg", "utf-8");  // 通知瀏覽器以下載的方式讀取資源 response.setHeader("content-disposition", "attachment;filename="+filename);  // 讀取圖片數(shù)據(jù) 發(fā)給ie瀏覽器 String webPath = "/download/美女.jpg"; // 相當(dāng)于當(dāng)前web應(yīng)用的path  ServletContext servletContext = super.getServletContext();  InputStream in = servletContext.getResourceAsStream(webPath);   OutputStream out = response.getOutputStream();   int len; byte[] buffer = new byte[1024]; while((len=in.read(buffer))!=-1)  out.write(buffer, 0, len);  }  public void doPost(HttpServletRequest request, HttpServletResponse response)  throws ServletException, IOException { doGet(request, response); } }