Jsp+Servlet实现文件上传下载 文件列表展示（二）(3/3)

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 list() { 
  Connection conn = DBUtil.getConnection(); 
  String sql = "select id,file_name,file_size,file_ext_name,file_path from tbl_accessory"; 
  List 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

 
 
  
 
 

文件列表
 
 
   
   
 
 
 
  
文件名
 
  
文件大小（KB）
 
  
操作
 
 
 
 
 
    
${acc.fileName}
 
    
${acc.fileSize}
 
    
删除
 
   
 
   
  
 
 
 

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 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 c language="java" %> 
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> 
 
 
  
 
 

上传失败：
 
 
 <%----%> 
 
${errorMessage}
 
 

 
 

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集合，每一个FileItem对应一个Form表单的输入项 
   List items = upload.parseRequest(request); 
   Iterator 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(); 
     //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); 
    } 

   } 

  } 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 { 
   if (!"".equals(errorMessage)) { 
    request.setAttribute("errorMessage", errorMessage); 
    request.getRequestDispatcher("pages/upload/error.jsp").forward(request, response); 
   } else { 
    response.sendRedirect("listUploadedFiles"); 
   } 

  } 

 } 

 @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[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！

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本站。

您可能感兴趣的文章:

• jsp+servlet实现文件上传与下载功能
• JSP servlet实现文件上传下载和删除
• Jsp+Servlet实现文件上传下载 文件上传（一）
• Jsp+Servlet实现文件上传下载 删除上传文件（三）