Jsp+Servlet实现文件上传下载 文件列表展示（二）
接着上一篇讲：Jsp+Servlet实现文件上传下载（一）--文件上传
本章来实现一下上传文件列表展示，同时优化了一下第一章中的代码。
废话少说，上代码
mysql创建附件表
DROP TABLE tbl_accessory;
CREATE TABLE tbl_accessory
(
id INT AUTO_INCREMENT PRIMARY KEY,
file_name VARCHAR(500),
file_size DOUBLE(10,2),
file_ext_name VARCHAR(100),
file_path VARCHAR(2000)
)
;
SELECT * FROM tbl_accessory;
DELETE FROM tbl_accessory;
创建附件实体类
package entity.upload;
/**
* 附件实体类
*
* @author xusucheng
* @create 2017-12-29
**/
public class EntityAccessory {
private int id;
private String fileName;
private double fileSize;
private String file_ext_name;
private String filePath;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = fileName;
}
public double getFileSize() {
return fileSize;
}
public void setFileSize(double fileSize) {
this.fileSize = fileSize;
}
public String getFile_ext_name() {
return file_ext_name;
}
public void setFile_ext_name(String file_ext_name) {
this.file_ext_name = file_ext_name;
}
public String getFilePath() {
return filePath;
}
public void setFilePath(String filePath) {
this.filePath = filePath;
}
}
创建DBUtil工具类
package util;
import java.sql.*;
import java.io.InputStream;
import java.util.Properties;
/**
* 数据库工具类
*
* @author xusucheng
* @create 2017-11-18
**/
public class DBUtil {
//定义链接所需要的变量
private static Connection con = null;
private static PreparedStatement ps = null;
private static ResultSet rs = null;
//定义链接数据库所需要的参数
private static String url = "";
private static String username = "";
private static String driver="";
private static String password="";
//定义读取配置文件所需要的变量
private static Properties pp = null;
private static InputStream fis = null;
/**
* 加载驱动
*/
static {
try {
//从dbinfo.properties配置文件中读取配置信息
pp = new Properties();
fis = DBUtil.class.getClassLoader().getResourceAsStream("db.properties");
pp.load(fis);
url = pp.getProperty("url");
username = pp.getProperty("username");
driver=pp.getProperty("driver");
password=pp.getProperty("password");
//加载驱动
Class.forName(driver);
} catch (Exception e) {
System.out.println("驱动加载失败！");
e.printStackTrace();
} finally {
try {
fis.close();
} catch (Exception e) {
e.printStackTrace();
}
fis = null; //垃圾回收自动处理
}
}
/**
* 得到Connection链接
* @return Connection
*/
public static Connection getConnection() {
try {
//建立连接
con = DriverManager.getConnection(url, username, password);
} catch (Exception e) {
System.out.println("数据库链接失败！");
e.printStackTrace();
}
return con;
}
/*public DBUtil(String sql){
try {
ps = getConnection().prepareStatement(sql);//准备执行语句
} catch (Exception e) {
e.printStackTrace();
}
}
public void close() {
try {
con.close();
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
}*/
/**
* 统一的资源关闭函数
* @param rs
* @param ps
* @param con
*/
public static void close(ResultSet rs,Statement ps, Connection con){
if(rs != null) {
try {
rs.close();
} catch (Exception e) {
e.printStackTrace();
}
}
if(ps != null) {
try {
ps.close();
} catch (Exception e) {
e.printStackTrace();
}
}
if(con != null) {
try {
con.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
创建附件实体DAO类
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 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();
}
}
}
创建list.jsp列表页面
<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="">删除</a></td>
</tr>
</c:forEach>
</c:if>
</table>
</body>
</html>
创建展示列表Servlet:listUploadedFilesServlet
package servlet.upload;
import dao.upload.AccessoryDao;
import entity.upload.EntityAccessory;
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;
import java.util.List;
/**
* 返回已上传文件列表
*
* @author xusucheng
* @create 2017-12-29
**/
@WebServlet("/listUploadedFiles")
public class listUploadedFilesServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取文件列表
List<EntityAccessory> accessoryList = AccessoryDao.list();
request.setAttribute("accessoryList", accessoryList);
request.getRequestDispatcher("pages/upload/list.jsp").forward(request, response);
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
}
增加error.jsp显示上传失败信息
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="https://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title>上传错误页面</title>
</head>
<body>
<h3>上传失败：</h3>
<c:if test="${not empty errorMessage}">
<%--<input type="text" id="errorMessage" value="${errorMessage}" style="color:red;" disabled="disabled">--%>
<h4 style="color: red;">${errorMessage}</h4>
</c:if>
</body>
</html> 优化了第一章中的上传控制器
package servlet.upload;
import dao.upload.AccessoryDao;
import entity.upload.EntityAccessory;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadBase;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.ProgressListener;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
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.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Calendar;
import java.util.Iterator;
import java.util.List;
import java.util.UUID;
/**
* 处理文件上传
*
* @author xusucheng
* @create 2017-12-27
**/
@WebServlet("/UploadServlet")
public class UploadServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置文件上传基本路径
String savePath = this.getServletContext().getRealPath("/WEB-INF/uploadFiles");
//设置临时文件路径
String tempPath = this.getServletContext().getRealPath("/WEB-INF/tempFiles");
File tempFile = new File(tempPath);
if (!tempFile.exists()) {
tempFile.mkdir();
}
//定义异常消息
String errorMessage = "";
//创建file items工厂
DiskFileItemFactory factory = new DiskFileItemFactory();
//设置缓冲区大小
factory.setSizeThreshold(1024 * 100);
//设置临时文件路径
factory.setRepository(tempFile);
//创建文件上传处理器
ServletFileUpload upload = new ServletFileUpload(factory);
//监听文件上传进度
ProgressListener progressListener = new ProgressListener() {
public void update(long pBytesRead, long pContentLength, int pItems) {
System.out.println("正在读取文件： " + pItems);
if (pContentLength == -1) {
System.out.println("已读取： " + pBytesRead + " 剩余0");
} else {
System.out.println("文件总大小：" + pContentLength + " 已读取：" + pBytesRead);
}
}
};
upload.setProgressListener(progressListener);
//解决上传文件名的中文乱码
upload.setHeaderEncoding("UTF-8");
//判断提交上来的数据是否是上传表单的数据
if (!ServletFileUpload.isMultipartContent(request)) {
//按照传统方式获取数据
return;
}
//设置上传单个文件的大小的最大值，目前是设置为1024*1024字节，也就是1MB
//upload.setFileSizeMax(1024 * 1024);
//设置上传文件总量的最大值，最大值=同时上传的多个文件的大小的最大值的和，目前设置为10MB
upload.setSizeMax(1024 * 1024 * 10);
try {
//使用ServletFileUpload解析器解析上传数据，解析结果返回的是一个List<FileItem>集合，每一个FileItem对应一个Form表单的输入项
List<FileItem> items = upload.parseRequest(request);
Iterator<FileItem> iterator = items.iterator();
while (iterator.hasNext()) {
FileItem item = iterator.next();
//判断jsp提交过来的是不是文件
if (item.isFormField()) {
errorMessage = "请提交文件！";
break;
} else {
//文件名
String fileName = item.getName();
if (fileName == null || fileName.trim() == "") {
System.out.println("文件名为空！");
}
//处理不同浏览器提交的文件名带路径问题
fileName = fileName.substring(fileName.lastIndexOf("\\") + 1);
//文件大小
Long fileSize = item.getSize();
//文件扩展名
String fileExtension = fileName.substring(fileName.lastIndexOf(".") + 1);
//判断扩展名是否合法
if (!validExtension(fileExtension)) {
errorMessage = "上传文件非法！";
item.delete();
break;
}
//获得文件输入流
InputStream in = item.getInputStream();
//得到保存文件的名称
String saveFileName = createFileName(fileName);
//得到文件保存路径
String realFilePath = createRealFilePath(savePath, saveFileName);
//创建文件输出流
FileOutputStream out = new FileOutputStream(realFilePath);
//创建缓冲区
byte buffer[] = new byte;
int len = 0;
while ((len = in.read(buffer)) > 0) {
//写文件
out.write(buffer, 0, len);
}
//关闭输入流
in.close();
//关闭输出流
out.close();
//删除临时文件
item.delete();
<span style="color:#FF0000;">//将上传文件信息保存到附件表中
EntityAccessory entity = new EntityAccessory();
entity.setFileName(fileName);
entity.setFileSize(fileSize);
entity.setFile_ext_name(fileExtension);
entity.setFilePath(realFilePath);
AccessoryDao.add(entity);</span>
}
}
} catch (FileUploadBase.FileSizeLimitExceededException e) {
e.printStackTrace();
errorMessage = "单个文件超出最大值！！！";
} catch (FileUploadBase.SizeLimitExceededException e) {
e.printStackTrace();
errorMessage = "上传文件的总的大小超出限制的最大值！！！";
} catch (FileUploadException e) {
e.printStackTrace();
errorMessage = "文件上传失败！！！";
} finally {
<span style="color:#FF0000;">if (!"".equals(errorMessage)) {
request.setAttribute("errorMessage", errorMessage);
request.getRequestDispatcher("pages/upload/error.jsp").forward(request, response);
} else {
response.sendRedirect("listUploadedFiles");
}</span>
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
private boolean validExtension(String fileExtension) {
String[] exts = {"jpg", "txt", "doc", "pdf"};
for (int i = 0; i < exts.length; i++) {
if (fileExtension.equals(exts)) {
return true;
}
}
return false;
}
private String createFileName(String fileName) {
return UUID.randomUUID().toString() + "_" + fileName;
}
/**
* 根据基本路径和文件名称生成真实文件路径，基本路径\\年\\月\\fileName
*
* @param basePath
* @param fileName
* @return
*/
private String createRealFilePath(String basePath, String fileName) {
Calendar today = Calendar.getInstance();
String year = String.valueOf(today.get(Calendar.YEAR));
String month = String.valueOf(today.get(Calendar.MONTH) + 1);
String upPath = basePath + File.separator + year + File.separator + month + File.separator;
File uploadFolder = new File(upPath);
if (!uploadFolder.exists()) {
uploadFolder.mkdirs();
}
String realFilePath = upPath + fileName;
return realFilePath;
}
}
测试效果截图
下集预告：实现附件删除功能！
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CodeAE代码之家。
https://www.uoften.com/program/jsp/20180413/48294.html
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