半江日月，观四季竞秀。一笔流年，写八方惊艳。北有苍山负雪，南有水湄流香。生逢何处，尽是良乡。愿时光如玉，别有温润，滚滚凡尘，浮生尽欢。
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 rel="nofollow noopener noreferrer" 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
本文Jsp+Servlet如何实现文件上传下载 删除上传文件（三）到此结束。我们日常生活中的情绪起伏，都会不可避免地影响周围的人；喜怒无常，也注定会破坏别人对自己的信任。所以，懂得做人，有时候比懂得做事更重要。即使你不懂怎么为人处世，至少也要学会控制情绪，而不要让情绪控制自己。小编再次感谢大家对我们的支持！
