Jsp+Servlet实现文件上传下载 文件列表展示（二），servlet文件上传分享

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

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 <%@ page contentType="text/html;charset=UTF-8" language="java" %>  <%@ taglib prefix="c" uri="

                                                        
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