Jsp+Servlet实现文件上传下载 删除上传文件(三)

网络转载  2018-01-02   作者:indexman   [简洁网络]

本文作者主要为大家详细介绍了Jsp+Servlet实现文件上传下载功能的第三部分删除上传文件,具有一定的参考价值,感兴趣的码友们可以参考一下

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:

删除后:

6.下集预告

实现文件下载功能

以上内容便是本文的全部内容,希望对广大码友们的学习有所帮助,也希望广大码友多多支持我们的简洁网络。

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