Jsp+Servlet实现文件上传下载删除上传文件（三）

2020-07-26 23:16:03

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接着上一篇讲：Jsp+Servlet实现文件上传下载（二）--文件列表展示

本章来实现一下删除已上传文件，同时优化了一下第一章中的代码。

废话少说，上代码得意

1.调整列表页面list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <html> <head>  <title>上传文件列表</title> </head> <body>  <h3>文件列表</h3> <table class="acclist_tab" border="1" bordercolor="#000000" cellspacing="0" cellpadding="2" style="border-collapse:collapse;">  <tr>   <th>文件名</th>   <th>文件大小（KB）</th>   <th>操作</th>  </tr>  <c:if test="${not empty accessoryList}">   <c:forEach items="${accessoryList}" var="acc">    <tr>     <td>${acc.fileName}</td>     <td>${acc.fileSize}</td>     <td><a href="<%=request.getContextPath()%>/removeUploadedFile?id=${acc.id}" rel="external nofollow" >删除</a></td>    </tr>   </c:forEach>  </c:if> </table> </body> </html>

2.新增FileUtils工具类

package util;  import java.io.File;  /**  * 文件操作工具类  *  * @author xusucheng  * @create 2017-12-30  **/ public class FileUtils {  public static boolean delete(String path){   File file = new File(path);   if(!file.isFile()){    System.out.println("删除失败，文件："+path+"不存在！");    return false;   }    file.delete();    return true;  } }

3.调整附件实体DAO，新增load方法

package dao.upload;  import entity.upload.EntityAccessory; import util.DBUtil;  import java.math.BigDecimal; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List;  /**  * 附件上传DAO  *  * @author xusucheng  * @create 2017-12-29  **/ public class AccessoryDao {  public static void add(EntityAccessory entity) {   Connection conn = DBUtil.getConnection();   String sql = "insert into tbl_accessory(file_name,file_size,file_ext_name,file_path) values(?,?,?,?)";   try {    PreparedStatement ps = conn.prepareStatement(sql);    ps.setString(1, entity.getFileName());    ps.setDouble(2, entity.getFileSize());    ps.setString(3, entity.getFile_ext_name());    ps.setString(4, entity.getFilePath());    ps.execute();    //conn.commit();     DBUtil.close(null, ps, conn);   } catch (SQLException e) {    e.printStackTrace();   }  }   public static List<EntityAccessory> list() {   Connection conn = DBUtil.getConnection();   String sql = "select id,file_name,file_size,file_ext_name,file_path from tbl_accessory";   List<EntityAccessory> accessoryList = new ArrayList<>();   try {    PreparedStatement ps = conn.prepareStatement(sql);    ResultSet rs = ps.executeQuery();     while (rs.next()) {     EntityAccessory entity = new EntityAccessory();     entity.setId(rs.getInt("id"));     entity.setFileName(rs.getString("file_name"));     entity.setFileSize(new BigDecimal(rs.getDouble("file_size") / 1024).setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue());     entity.setFile_ext_name(rs.getString("file_ext_name"));     entity.setFilePath(rs.getString("file_path"));     accessoryList.add(entity);    }     DBUtil.close(rs, ps, conn);   } catch (SQLException e) {    e.printStackTrace();   }    return accessoryList;   }   public static EntityAccessory load(int id){   Connection conn = DBUtil.getConnection();   PreparedStatement ps=null;   ResultSet rs=null;   EntityAccessory entity = new EntityAccessory();   String sql = "select id, file_name,file_size,file_ext_name,file_path from tbl_accessory where id=?";   try {    ps = conn.prepareStatement(sql);    ps.setInt(1,id);    rs = ps.executeQuery();    while (rs.next()){     entity.setId(rs.getInt("id"));     entity.setFileName(rs.getString("file_name"));     entity.setFileSize(rs.getDouble("file_size"));     entity.setFile_ext_name(rs.getString("file_ext_name"));     entity.setFilePath(rs.getString("file_path"));    }   } catch (SQLException e) {    e.printStackTrace();   }finally {    DBUtil.close(rs,ps,conn);   }    return entity;  }   public static void remove(int id) {   Connection conn = DBUtil.getConnection();   String sql = "delete from tbl_accessory where id=?";   try {    PreparedStatement ps = conn.prepareStatement(sql);    ps.setInt(1,id);    ps.execute();    //conn.commit(); mysql默认开启了autocommit     DBUtil.close(null,ps,conn);   } catch (SQLException e) {    e.printStackTrace();   }  } }

4.新增删除文件处理器，removeUploadedFileServlet

package servlet.upload;  import dao.upload.AccessoryDao; import entity.upload.EntityAccessory; import util.FileUtils;  import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException;  /**  * 删除已上传文件  *  * @author xusucheng  * @create 2017-12-30  **/ @WebServlet("/removeUploadedFile") public class removeUploadedFileServlet extends HttpServlet {  @Override  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {   //String filePath = request.getParameter("filePath");   int fileId = Integer.valueOf(request.getParameter("id"));   EntityAccessory entity = AccessoryDao.load(fileId);   //删除文件   FileUtils.delete(entity.getFilePath());   //删除数据库记录   AccessoryDao.remove(fileId);    //跳回到文件列表页   //request.getRequestDispatcher("listUploadedFiles").forward(request, response);   response.sendRedirect("listUploadedFiles");  }   @Override  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {   doPost(request, response);  }   }

5.测试效果截图

删除前：