JSP文件上传下载-----下载篇

来源：互联网发布：python招聘工资怎么样编辑：程序博客网时间：2024/06/18 08:39

上次实现了文件上传到本地磁盘并插入到了数据库，接下来就让我们将上传的资源实现下载的功能：

在显示所有文件的JSP中：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>文件下载页面</title>  </head>  <body>    <table>    <thead>    <tr>    <th>id</th><th>name</th><th>fileName</th><th>operator</th>    </tr>    </thead>    <tbody>    <c:forEach var="files" items="${list }">    <tr>    <td>    ${files.id}    </td>    <td>    ${files.name}    </td>    <td>    ${files.fileName}    </td>    <td>    <a href="${pageContext.request.contextPath}/download.do?filePath=${files.filePath}&fileName=${files.fileName}">下载</a>    </td>    </tr>    </c:forEach>    </tbody>    </table>  </body></html>

实现浏览的servlet中：

package cn.csdn.web.servlet;import java.io.IOException;import java.sql.SQLException;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import cn.csdn.web.dao.UploadDao;import cn.csdn.web.dao.UploadDaoImpl;import cn.csdn.web.domain.Upload;public class ListFilesServlet extends HttpServlet {UploadDao uDao = new UploadDaoImpl();public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {request.setCharacterEncoding("utf-8");try {List<Upload> list = uDao.checkAll();List<Upload> entities = new ArrayList();Map map = new HashMap();for(Upload entity : list){String fileName = entity.getFileName();String realName = fileName.substring(fileName.lastIndexOf("_")+1);entity.setFileName(realName);System.out.println("-----"+entity.getFilePath());entities.add(entity);}request.setAttribute("list", entities);request.getRequestDispatcher("/listfiles.jsp").forward(request, response);} catch (SQLException e) {e.printStackTrace();}}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doGet(request, response);}}

下面是实现下载功能的servlet：

package cn.csdn.web.servlet;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.net.URLEncoder;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 {String filePath = request.getParameter("filePath");//拿到请求中的文件路径String fileName = filePath.substring(filePath.lastIndexOf("_")+1);//得到文件的真实名字filePath = new String(filePath.getBytes("iso8859-1"),"utf-8");fileName = new String(fileName.getBytes("iso8859-1"),"utf-8");fileName = URLEncoder.encode(fileName,"utf-8");File file = new File(filePath);if(!file.exists()){request.setAttribute("message","要下载的文件不存在");request.getRequestDispatcher("/message.jsp").forward(request, response);}else{response.setHeader("content-disposition", "attachment;filename="+fileName);FileInputStream fis = new FileInputStream(file);java.io.OutputStream os = response.getOutputStream();byte[] buffer = new byte[1024];int len = 0;while((len=fis.read(buffer))!=-1){os.write(buffer, 0, len);}fis.close();}}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doGet(request, response);}}