接著上一篇講：
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 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 border="1" bordercolor="#000000" cellspacing="0" cellpadding="2">  <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   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}" disabled="disabled">--%>  <h4>${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List<FileItem>集合，每一個FileItem對應一個Form表單的輸入項    List<FileItem> items = upload.parseRequest(request);    Iterator<FileItem> 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>//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>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！

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持。