Jsp+Servlet实现文件上传下载删除上传文件（三）

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：