javaweb 下载文件

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resp.sendRedirect("网页地址"); 网页重定向

// 设置字符串的编码

req.setCharacterEncoding("utf-8");

resp.setContentType("text/html;charset=utf-8");

resp.setCharacterEncoding("utf-8");

// 写入界面

PrintWriter out = resp.getWriter();

out.print("内容");

// 获得配置文件中共有的那个配置文件

ServletContext sc = this.getServletContext();

// 苹果字符编码

ios-8859-1

// 下载文档下载的文件还会乱码还未处理

//JAVA代码

package download;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.swing.filechooser.FileNameExtensionFilter;

public class DownloadSever extends HttpServlet {

   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

// 呈现了web应用的Servlet视图

ServletContext sc = this.getServletContext();

// 设置文件格式

        resp.setCharacterEncoding("utf-8");
       req.setCharacterEncoding("utf-8");
       resp.setContentType("text/html;charset = utf-8");

// 得到HTML文件中的标签的 fileName
String fileName = req.getParameter("fileName");

// 设置字符编码格式

String strname = new String(fileName.getBytes("ISO-8859-1"),"utf-8");
System.out.println(strname);

//下载不同的文件

        if(strname.equals("AJAX基础.ppt")){
           down(resp,sc,"PPT/AJAX基础.ppt",".ppt");
       }else if(strname.equals("赵丽颖.jpg")){
           down(resp,sc,"image/赵丽颖.jpg",".jpg");
       }
   }
   /**
   * 下载文档
   * @param resp    响应
   * @param sc     整个文档公有的对象
   * @param path2    文件路径
   * @param form   下载的格式
   */
   public void down(HttpServletResponse resp,ServletContext sc,String path2,String form){
       resp.setHeader("Content-Disposition", "attachment; filename="+System.currentTimeMillis()+form);
       String path = sc.getRealPath(path2);
       // 得到写入流
       FileInputStream fis;
       try {
           fis = new FileInputStream(new File(path));
           ServletOutputStream sos= resp.getOutputStream();
           byte[] by = new byte[1024];
           int length = 0;
           while((length =fis.read() )!=-1 ){
               sos.write(by,0,length);
           }
       } catch (FileNotFoundException e) {
           e.printStackTrace();
       } catch (IOException e) {
           e.printStackTrace();
       }

   }

   @Override
   protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       // TODO Auto-generated method stub
       doGet(req, resp);
   }

// HTML文件

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="DownloadSever?fileName=AJAX基础.ppt">下载AJAX基础.ppt</a>
<a href="DownloadSever?fileName=赵丽颖.jpg">下载赵丽颖图片</a>
</body>
</html>

// 配置文件

<servlet>
    <servlet-name>DownloadSever</servlet-name>
    <servlet-class>download.DownloadSever</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>DownloadSever</servlet-name>
    <url-pattern>/DownloadSever</url-pattern>
</servlet-mapping>}

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