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Jsp+Servlet實現文件上傳下載 刪除上傳文件（三）
瀏覽：3日期：2022-06-07 16:45:46
接著上一篇講：Jsp+Servlet實現文件上傳下載（二）--文件列表展示
本章來實現一下刪除已上傳文件，同時優化了一下第一章中的代碼。
廢話少說，上代碼得意
1.調整列表頁面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>上傳文件列表</title> </head> <body> <h3>文件列表</h3> <table border="1" bordercolor="#000000" cellspacing="0" cellpadding="2"> <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" >刪除</a></td> </tr> </c:forEach> </c:if> </table> </body> </html> 2.新增FileUtils工具類
package util; import java.io.File; /** * 文件操作工具類 * * @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("刪除失敗，文件："+path+"不存在！"); return false; } file.delete(); return true; } } 3.調整附件實體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; /** * 附件上傳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默認開啟了autocommit DBUtil.close(null,ps,conn); } catch (SQLException e) { e.printStackTrace(); } } } 4.新增刪除文件處理器，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; /** * 刪除已上傳文件 * * @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); //刪除文件 FileUtils.delete(entity.getFilePath()); //刪除數據庫記錄 AccessoryDao.remove(fileId); //跳回到文件列表頁 //request.getRequestDispatcher("listUploadedFiles").forward(request, response); response.sendRedirect("listUploadedFiles"); } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } } 5.測試效果截圖
刪除前：
刪除后：
6.下集預告
實現文件下載功能
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持。
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