Jsp+Servlet实现文件上传下载删除上传文件（三）-JSP技巧-JSP编程-硕编程

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Jsp+Servlet实现文件上传下载删除上传文件（三）

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

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持硕编程。

JSP技巧