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Jsp+Servlet實現文件上傳下載（一）--文件上傳

本章來實現一下上傳文件列表展示，同時優化了一下第一章中的代碼。

廢話少說，上代碼

mysql創建附件表

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;

創建附件實體類

package entity.upload; 
 
/** 
 * 附件實體類 
 * 
 * @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; 
 } 
}

創建DBUtil工具類

package util; 
 
import java.sql.*; 
import java.io.InputStream; 
import java.util.Properties; 
 
/** 
 * 數據庫工具類 
 * 
 * @author xusucheng 
 * @create 2017-11-18 
 **/ 
public class DBUtil { 
 //定義鏈接所需要的變量 
 private static Connection con = null; 
 private static PreparedStatement ps = null; 
 private static ResultSet rs = null; 
 
 //定義鏈接數據庫所需要的參數 
 private static String url = ""; 
 private static String username = ""; 
 private static String driver=""; 
 private static String password=""; 
 
 //定義讀取配置文件所需要的變量 
 private static Properties pp = null; 
 private static InputStream fis = null; 
 
 /** 
  * 加載驅動 
  */ 
 static { 
  try { 
   //從dbinfo.properties配置文件中讀取配置信息 
   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"); 
 
   //加載驅動 
   Class.forName(driver); 
 
  } catch (Exception e) { 
   System.out.println("驅動加載失敗！"); 
   e.printStackTrace(); 
  } finally { 
   try { 
    fis.close(); 
   } catch (Exception e) { 
    e.printStackTrace(); 
   } 
 
   fis = null; //垃圾回收自動處理 
  } 
 
 } 
 
 /** 
  * 得到Connection鏈接 
  * @return Connection 
  */ 
 public static Connection getConnection() { 
 
  try { 
   //建立連接 
   con = DriverManager.getConnection(url, username, password); 
 
  } catch (Exception e) { 
   System.out.println("數據庫鏈接失敗！"); 
   e.printStackTrace(); 
  } 
 
  return con; 
 } 
 
 /*public DBUtil(String sql){ 
  try { 
   ps = getConnection().prepareStatement(sql);//準備執行語句 
  } catch (Exception e) { 
   e.printStackTrace(); 
  } 
 } 
 
 public void close() { 
  try { 
   con.close(); 
   ps.close(); 
  } catch (SQLException e) { 
   e.printStackTrace(); 
  } 
 }*/ 
 
 /** 
  * 統一的資源關閉函數 
  * @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(); 
   } 
  } 
 } 
 
}

創建附件實體DAO類

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; 
 
/** 
 * 附件上傳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 ListEntityAccessory> list() { 
  Connection conn = DBUtil.getConnection(); 
  String sql = "select id,file_name,file_size,file_ext_name,file_path from tbl_accessory"; 
  ListEntityAccessory> 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默認開啟了autocommit 
 
   DBUtil.close(null,ps,conn); 
  } catch (SQLException e) { 
   e.printStackTrace(); 
  } 
 } 
}

創建list.jsp列表頁面

html> 
head> 
 title>上傳文件列表/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="">刪除/a>/td> 
   /tr> 
  /c:forEach> 
 /c:if> 
/table> 
/body> 
/html>

創建展示列表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; 
 
/** 
 * 返回已上傳文件列表 
 * 
 * @author xusucheng 
 * @create 2017-12-29 
 **/ 
 
@WebServlet("/listUploadedFiles") 
public class listUploadedFilesServlet extends HttpServlet { 
 @Override 
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
  //獲取文件列表 
  ListEntityAccessory> 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顯示上傳失敗信息

%@ page contentType="text/html;charset=UTF-8" language="java" %> 
%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> 
html> 
head> 
 title>上傳錯誤頁面/title> 
/head> 
body> 
 
h3>上傳失敗：/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>

優化了第一章中的上傳控制器

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; 
 
/** 
 * 處理文件上傳 
 * 
 * @author xusucheng 
 * @create 2017-12-27 
 **/ 
@WebServlet("/UploadServlet") 
public class UploadServlet extends HttpServlet { 
 @Override 
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
  //設置文件上傳基本路徑 
  String savePath = this.getServletContext().getRealPath("/WEB-INF/uploadFiles"); 
  //設置臨時文件路徑 
  String tempPath = this.getServletContext().getRealPath("/WEB-INF/tempFiles"); 
  File tempFile = new File(tempPath); 
  if (!tempFile.exists()) { 
   tempFile.mkdir(); 
  } 
 
  //定義異常消息 
  String errorMessage = ""; 
  //創建file items工廠 
  DiskFileItemFactory factory = new DiskFileItemFactory(); 
  //設置緩沖區大小 
  factory.setSizeThreshold(1024 * 100); 
  //設置臨時文件路徑 
  factory.setRepository(tempFile); 
  //創建文件上傳處理器 
  ServletFileUpload upload = new ServletFileUpload(factory); 
  //監聽文件上傳進度 
  ProgressListener progressListener = new ProgressListener() { 
   public void update(long pBytesRead, long pContentLength, int pItems) { 
    System.out.println("正在讀取文件： " + pItems); 
    if (pContentLength == -1) { 
     System.out.println("已讀取： " + pBytesRead + " 剩余0"); 
    } else { 
     System.out.println("文件總大小：" + pContentLength + " 已讀取：" + pBytesRead); 
    } 
   } 
  }; 
  upload.setProgressListener(progressListener); 
 
  //解決上傳文件名的中文亂碼 
  upload.setHeaderEncoding("UTF-8"); 
  //判斷提交上來的數據是否是上傳表單的數據 
  if (!ServletFileUpload.isMultipartContent(request)) { 
   //按照傳統方式獲取數據 
   return; 
  } 
 
  //設置上傳單個文件的大小的最大值，目前是設置為1024*1024字節，也就是1MB 
  //upload.setFileSizeMax(1024 * 1024); 
  //設置上傳文件總量的最大值，最大值=同時上傳的多個文件的大小的最大值的和，目前設置為10MB 
  upload.setSizeMax(1024 * 1024 * 10); 
 
  try { 
   //使用ServletFileUpload解析器解析上傳數據，解析結果返回的是一個ListFileItem>集合，每一個FileItem對應一個Form表單的輸入項 
   ListFileItem> items = upload.parseRequest(request); 
   IteratorFileItem> iterator = items.iterator(); 
   while (iterator.hasNext()) { 
    FileItem item = iterator.next(); 
 
    //判斷jsp提交過來的是不是文件 
    if (item.isFormField()) { 
     errorMessage = "請提交文件！"; 
     break; 
    } else { 
     //文件名 
     String fileName = item.getName(); 
     if (fileName == null || fileName.trim() == "") { 
      System.out.println("文件名為空！"); 
     } 
     //處理不同瀏覽器提交的文件名帶路徑問題 
     fileName = fileName.substring(fileName.lastIndexOf("\\") + 1); 
     //文件大小 
     Long fileSize = item.getSize(); 
     //文件擴展名 
     String fileExtension = fileName.substring(fileName.lastIndexOf(".") + 1); 
     //判斷擴展名是否合法 
     if (!validExtension(fileExtension)) { 
      errorMessage = "上傳文件非法！"; 
      item.delete(); 
      break; 
     } 
     //獲得文件輸入流 
     InputStream in = item.getInputStream(); 
     //得到保存文件的名稱 
     String saveFileName = createFileName(fileName); 
     //得到文件保存路徑 
     String realFilePath = createRealFilePath(savePath, saveFileName); 
     //創建文件輸出流 
     FileOutputStream out = new FileOutputStream(realFilePath); 
     //創建緩沖區 
     byte buffer[] = new byte[1024]; 
     int len = 0; 
     while ((len = in.read(buffer)) > 0) { 
      //寫文件 
      out.write(buffer, 0, len); 
     } 
     //關閉輸入流 
     in.close(); 
     //關閉輸出流 
     out.close(); 
     //刪除臨時文件 
     item.delete(); 
     span style="color:#FF0000;">//將上傳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 = "單個文件超出最大值！！！"; 
  } catch (FileUploadBase.SizeLimitExceededException e) { 
   e.printStackTrace(); 
   errorMessage = "上傳文件的總的大小超出限制的最大值！！！"; 
  } catch (FileUploadException e) { 
   e.printStackTrace(); 
   errorMessage = "文件上傳失敗！！！"; 
  } 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[i])) { 
    return true; 
   } 
 
  } 
 
  return false; 
 } 
 
 private String createFileName(String fileName) { 
  return UUID.randomUUID().toString() + "_" + fileName; 
 } 
 
 /** 
  * 根據基本路徑和文件名稱生成真實文件路徑，基本路徑\\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; 
 } 
}

測試效果截圖

下集預告：實現附件刪除功能！

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Jsp+Servlet實現文件上傳下載 文件列表展示（二）

Jsp+Servlet實現文件上傳下載文件列表展示（二）