JAVA-使用commos-fileupload实现文件上传与下载

时间：2022-04-27 05:12:18

一文件的上传

实体类

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import java.sql.Timestamp;  

/**

 *

 * @Decription 文件上传实体类

 * @author 刘楠

 *

 * @time2016-1-31上午11:17:46

 */

public class Upfile {  

    private String id;// ID主键 使用uuid随机生成

    private String uuidname; // UUID名称

    private String filename;//文件名称

    private String savepath; // 保存路径

    private Timestamp uploadtime; // 上传时间

    private String description;// 文件描述

    private String username; // 用户名  

    public Upfile() {

        super();

    }  

    public Upfile(String id, String uuidname, String filename, String savepath,

            Timestamp uploadtime, String description, String username) {

        super();

        this.id = id;

        this.uuidname = uuidname;

        this.filename = filename;

        this.savepath = savepath;

        this.uploadtime = uploadtime;

        this.description = description;

        this.username = username;

    }  

    public String getDescription() {

        return description;

    }  

    public String getFilename() {

        return filename;

    }  

    public String getId() {

        return id;

    }  

    public String getSavepath() {

        return savepath;

    }  

    public Timestamp getUploadtime() {

        return uploadtime;

    }  

    public String getUsername() {

        return username;

    }  

    public String getUuidname() {

        return uuidname;

    }  

    public void setDescription(String description) {

        this.description = description;

    }  

    public void setFilename(String filename) {

        this.filename = filename;

    }  

    public void setId(String id) {

        this.id = id;

    }  

    public void setSavepath(String savepath) {

        this.savepath = savepath;

    }  

    public void setUploadtime(Timestamp uploadtime) {

        this.uploadtime = uploadtime;

    }  

    public void setUsername(String username) {

        this.username = username;

    }  

    public void setUuidname(String uuidname) {

        this.uuidname = uuidname;

    }  

}

页面

 
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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%

String path = request.getContextPath();

String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>  

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

  <head>

    <base href="<%=basePath%>">  

    <title>My JSP 'upload.jsp' starting page</title>  

    <meta http-equiv="pragma" content="no-cache">

    <meta http-equiv="cache-control" content="no-cache">

    <meta http-equiv="expires" content="0">

    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

    <meta http-equiv="description" content="This is my page">

    <!--

    <link rel="stylesheet" type="text/css" href="styles.css">

    -->  

  </head>  

  <body>

    <h1>文件上传</h1>

    <form action="${pageContext.request.contextPath }/upload" method="post" enctype="multipart/form-data">

   <table>

   <tr>

   <td> 上传用户名:</td>

   <td><input type="text" name="username"/></td>

   </tr>

   <tr>

   <td> 上传文件:</td>

   <td><input type="file" name="file"/></td>

   </tr>

   <tr>

   <td> 描述:</td>

   <td><textarea rows="5" cols="50" name="description"></textarea></td>

   </tr>

    <tr>

   <td><input type="submit" value="上传开始"/></td>

   </tr>

   </table>

    </form>

    <div>${msg }</div>

    <a href="${pageContext.request.contextPath  }/index.jsp">返回主页</a>

  </body>

</html>

Servlet

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import java.io.IOException;  

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;  

import org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException;

import org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException;

import org.apache.commons.fileupload.servlet.ServletFileUpload;  

import com.itheima.domain.Upfile;

import com.itheima.exception.MyException;

import com.itheima.service.UpfileService;

import com.itheima.service.impl.UpfileServiceImpl;

import com.itheima.untils.WebUntil;  

public class UploadFileServlet extends HttpServlet {  

    public void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {  

        doPost(request, response);

    }  

    public void doPost(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        //判断表单是不是多个部分组成的

        if(!ServletFileUpload.isMultipartContent(request)){  

            request.setAttribute("msg", "表单个设置错误,请检查enctype属性是是否设置正确");

            request.getRequestDispatcher("/upload.jsp").forward(request, response);

            return ;

        }

        //是多部分组成的就获取并遍历返回一个文件上传对象,包含上传的所有信息

        try {

            Upfile upfile=WebUntil.upload(request);  

            UpfileService upfileService=new UpfileServiceImpl();

            boolean flag=upfileService.add(upfile);  

            if(flag){

                request.setAttribute("msg", "上传成功");

                request.getRequestDispatcher("/upload.jsp").forward(request, response);

                return ;

            }else{

                request.setAttribute("msg", "上传失败,请重试");

                request.getRequestDispatcher("/upload.jsp").forward(request, response);

                return ;

            }  

        }catch (FileSizeLimitExceededException e) {

            e.printStackTrace();

            request.setAttribute("msg", "单个文件大小 ,超过最大限制");

            request.getRequestDispatcher("/upload.jsp").forward(request, response);

            return ;

        } catch (SizeLimitExceededException e) {

            e.printStackTrace();

            request.setAttribute("msg", "总文件大小 ,超过最大限制");

            request.getRequestDispatcher("/upload.jsp").forward(request, response);

            return ;

        }  

    }  

}

工具类

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import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.UnsupportedEncodingException;

import java.util.ArrayList;

import java.util.List;

import java.util.UUID;  

import javax.servlet.http.HttpServletRequest;  

import org.apache.commons.fileupload.FileItem;

import org.apache.commons.fileupload.FileUploadBase;

import org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException;

import org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException;

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 com.itheima.domain.Upfile;

import com.itheima.exception.MyException;

/**

 * 文件上传工具类

* @Decription TODO

 * @author 刘楠

 *

 * @time2016-1-31下午12:56:02

 */

public class WebUntil {  

    /**

     * 文件上传的方法

     * @param request  请求参数传入

     * @return  返回一个Upfile对象

     * @throws FileSizeLimitExceededException

     * @throws SizeLimitExceededException

     * @throws IOException

     */

    public static Upfile upload(HttpServletRequest request) throws FileSizeLimitExceededException, SizeLimitExceededException {

        Upfile upfile=new Upfile();

        ArrayList<String> fileList=initList();

        try {

        //获取磁盘文件对象工厂

        DiskFileItemFactory factory=new DiskFileItemFactory();

        String tmp=request.getSession().getServletContext().getRealPath("/tmp");

        System.out.println(tmp);

        //初始化工厂

        setFactory(factory,tmp);

        //获取文件上传解析器

        ServletFileUpload upload=new ServletFileUpload(factory);

        //初始化解析器

        setUpload(upload);

        //获取文件列表集合

            List<FileItem> list = upload.parseRequest(request);

            //遍历

            for (FileItem items : list) {

                //判断 是不是普通表单个对象

                if(items.isFormField()){

                    //获取上传表单的name

                    String fieldName=items.getFieldName();

                    //value

                    String fieldValue=items.getString("UTF-8");

                    //判断

                    if("username".equals(fieldName)){

                        //设置  

                        upfile.setUsername(fieldValue);

                    }else if("description".equals(fieldName)){

                        //设置属性

                        upfile.setDescription(fieldValue);

                    }  

                }else{

                    //是文件就准备上传

                    //获取文件名

                    String filename=items.getName();

                    //处理因为浏览器不同而导致的 获得 的  文件名的 差异

                    int index=filename.lastIndexOf("\\");

                    if(index!=-1){

                        filename=filename.substring(index+1);

                    }  

                    //生成随机的文件名  

                    String uuidname=generateFilename(filename);  

                    //获取上传的文件路径

                    String savepath=request.getSession().getServletContext().getRealPath("/WEB-INF/upload");

                    //获取请求对象中的输入流

                    InputStream in = items.getInputStream();

                    //将文件打散存放在不同的路径,求出路径

                    savepath=generateRandomDir(savepath,uuidname);  

                    //复制文件  

                    uploadFile(in,savepath,uuidname);

                    String id=UUID.randomUUID().toString();

                    upfile.setId(id);

                    upfile.setSavepath(savepath);

                    upfile.setUuidname(uuidname);

                    upfile.setFilename(filename);

                    //清除缓存

                    items.delete();

                }  

            }  

        }catch ( FileUploadBase.FileSizeLimitExceededException e) {

            //抛出出异常

            throw e;

        } catch (FileUploadBase.SizeLimitExceededException e) {

            //抛出出异常

            throw e;

        }catch (FileUploadException e) {

            e.printStackTrace();

        } catch (UnsupportedEncodingException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        } catch (Exception e) {

            e.printStackTrace();

        }  

        return upfile;

    }  

    /**

     * 初始化文件列表

     * @return

     */

    private static ArrayList<String> initList() {

         ArrayList<String>   list=new ArrayList<String>();

           list.add(".jpg");

           list.add(".rar");

           list.add(".txt");

           list.add(".png");  

           return  list;

    }  

    /**

     * 复制文件

     * @param in items中的输入流

     * @param savepath 保存路径

     * @param uuidname 文件名

     */

    private static void uploadFile(InputStream in, String savepath,

            String uuidname) {

        //获取文件

        File file=new File(savepath, uuidname);

        OutputStream out = null;

        try {

            int len=0;

            byte [] buf=new byte[1024];

        //获取输出流

            out = new FileOutputStream(file);

            while((len=in.read(buf))!=-1){

                out.write(buf, 0, len);

            }  

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }finally{

            try {

                in.close();

            } catch (IOException e) {

                e.printStackTrace();

            }

            try {

                out.close();

            } catch (IOException e) {

                e.printStackTrace();

            }

        }  

    }  

    /**

     * 生成随机的存放路径

     * @param savepath 保存路径

     * @param uuidname  生成的uuid名称

     * @return

     * 使用hashcode完成

     */

    private static String generateRandomDir(String savepath, String uuidname) {

        //转化为hashcode

        System.out.println("上传路径"+savepath);

        System.out.println("UUIDNAME"+uuidname);

        int hashcode=uuidname.hashCode();

        //容器

        StringBuilder sb=new StringBuilder();

        while(hashcode>0){

            //与上15

            int tmp=hashcode&0xf;  

            sb.append("/");

            sb.append(tmp+"");

            hashcode=hashcode>>4;

        }

        //拼接新的路径

        String path=savepath+sb.toString();

        System.out.println("path"+path);

        File file=new File(path);

        //判断路径存不存在

        if(!file.exists()){

            //不存在就创建

            file.mkdirs();

        }  

        //返回保存路径

        return path;

    }  

    /**

     * 生成新的文件名

     * @param uuidname 随机的ID名字

     * @param filename 原来的名

     * @return

     */

    private static String generateFilename( String filename) {

        String uuidname=UUID.randomUUID().toString();

        return uuidname.replace("-", "").toString()+"_"+filename;

    }  

    /**

     * 初始化解析器

     * @param upload

     */

    private static void setUpload(ServletFileUpload upload) {

        // 设置 字符编码

        upload.setHeaderEncoding("utf-8");

        //设置文件大小

        upload.setFileSizeMax(1024*1024*20);

        //设置总文件大小

        upload.setSizeMax(1024*1024*50);

        //设置进度监听器

        upload.setProgressListener(new ProgressListener() {  

            public void update(long pBytesRead, long pContentLength, int pItems) {

                System.out.println("已经读取:  "+pBytesRead+",总共有: "+pContentLength+", 第"+pItems+"个");  

            }

        });   

    }  

    /**

     * 工厂初始化方法

     * @param factory

     * @param tmp  缓冲目录

     */

    private static void setFactory(DiskFileItemFactory factory, String tmp) {

        /// 配置初始化值缓冲区

        factory.setSizeThreshold(1024*1024);

        File file=new File(tmp);

        //设置缓冲目录

        factory.setRepository(file);  

    }  

}

二文件下载

Servlet

public class DownupfileServlet extends HttpServlet {  

    public void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {  

        doPost(request, response);

    }  

    public void doPost(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        //获取ID

        String id=request.getParameter("id");

        //业务层的接口

        UpfileService upfileService=new UpfileServiceImpl();

        //根据ID查找这个对象

        Upfile upfile=upfileService.findUpfileById(id);

        if(upfile==null){

            return;

        }

        //获取文件的真实名称

        String filename=upfile.getFilename();

        //如果文件名中有中文,需要转码,不然就下载时没有文件名

        filename=URLEncoder.encode(filename, "utf-8");

        //更改过的名称

        String uuidname=upfile.getUuidname();

        //保存路径

        String savepath=upfile.getSavepath();

        File file=new File(savepath,uuidname);

        //判断文件 是否存在

        if(!file.exists()){

            request.setAttribute("msg", "下载 的文件过期了");

            request.getRequestDispatcher("/index").forward(request, response);

            return;

        }

        //设置文件下载响应头信息

        response.setHeader("Content-disposition", "attachement;filename="+filename);

        //使用IO流输出

        InputStream in = new FileInputStream(file);

        ServletOutputStream out = response.getOutputStream();

        int len=0;

        byte [] buf=new byte[1024];

        while((len=in.read(buf))!=-1){

            out.write(buf, 0, len);

        }

        in.close();  

    }  

}
 

数据库

create database upload_download_exercise;

use upload_download_exercise;

create table upfiles(

   id varchar(100), //使用UUID生成

   uuidname varchar(255),//uuid加上原来的文件名

   filename varchar(100),//真实文件名

   savepath varchar(255),//保存路径

   uploadtime timestamp,//上传时间

   description varchar(255),//描述

   username varchar(10) 上传人

);

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