Jsp+Servlet实现文件上传下载 文件列表展示（二）

这篇文章主要为大家详细介绍了Jsp+Servlet实现文件上传下载功能的第二部分，文件列表展示，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

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 {@Overrideprotected 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);} @Overrideprotected 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="http://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 {@Overrideprotected 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[1024];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>} } @Overrideprotected 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[i])) { 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！