深入体验javaWeb开发内幕——问件的上传与下载案例实现

最新推荐文章于 2025-04-26 10:47:04 发布

置顶 lijizh1013

最新推荐文章于 2025-04-26 10:47:04 发布

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本文介绍了一个基于Java实现的文件上传与下载系统，包括文件的上传、存储、下载及管理功能。系统通过数据库存储文件元信息，并提供界面供用户进行文件操作。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

遍历上传目录下的所有文件显示给用户，并允许用户完成下载。

（读取某一个文件夹下的所有的文件，存到集合里面List，再存到request作用域范围中）。

一个表的相关字段：

CREATETABLE `upfile` (

`id` varchar(50) NOT NULL,

`uuidname` varchar(255) NOT NULL,

`realname` varchar(255) NOT NULL,

`savepath` varchar(255) NOT NULL,

`uptime` datetime NOT NULL,

`description` varchar(255) DEFAULT NULL,

`username` varchar(40) DEFAULT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB DEFAULTCHARSET=utf8;

一个实体类：

  publicclass UploadFile {

 

    privateString id ;

    private String uuidname ;

    private String realname;

    private String savepath ;

    private Date uptime ;

    private String description ;

    private String username ;

   

    public String getId() {

       returnid;

    }

    publicvoid setId(String id) {

       this.id = id;

    }

    public StringgetUuidname() {

       returnuuidname;

    }

    publicvoid setUuidname(String uuidname) {

       this.uuidname = uuidname;

    }

    public StringgetRealname() {

       returnrealname;

    }

    publicvoid setRealname(String realname) {

       this.realname = realname;

    }

    public StringgetSavepath() {

       returnsavepath;

    }

    publicvoid setSavepath(String savepath) {

       this.savepath = savepath;

    }

    public Date getUptime(){

       returnuptime;

    }

    publicvoid setUptime(Date uptime) {

       this.uptime = uptime;

    }

    public StringgetDescription() {

       returndescription;

    }

    publicvoid setDescription(String description) {

       this.description = description;

    }

    public StringgetUsername() {

       returnusername;

    }

    publicvoid setUsername(String username) {

       this.username = username;

    }

}

一个dao接口：

 public  interface UploadFileDao {

  publicvoid insert(UploadFile f);

 

  public UploadFilegetUploadFile(String id);

 

  publicList<UploadFile> getUploadFiles();

}

该接口的实现类：

publicclass UploadFileDaoImpl implements UploadFileDao{

 

    @Override

    public UploadFilegetUploadFile(String id) {

       QueryRunner qr = new QueryRunner(DBManager.getDataSource());

       String sql = "selectid,uuidname,realname,savepath,uptime,description,username from  uploadfile where id=?";

       try {

           UploadFile uf = qr.query(sql,id,new BeanHandler(UploadFile.class));

           return uf;

       } catch(SQLException e) {

           thrownew RuntimeException(e);

       }

    }

 

    @Override

    publicList<UploadFile> getUploadFiles() {

       QueryRunner qr = new QueryRunner(DBManager.getDataSource());

       String sql = "selectid,uuidname,realname,savepath,uptime,description,username from  uploadfile order by uptime desc";

       try {

           List<UploadFile> list = qr.query(sql,new BeanListHandler(UploadFile.class));

           return list;

       } catch(SQLException e) {

           thrownew RuntimeException(e);

       }

    }

 

    @Override

    publicvoid insert(UploadFile f) {

      

       QueryRunner qr = new QueryRunner(DBManager.getDataSource());

       String sql = "insert into uploadfile(id,uuidname,realname,savepath,uptime,description,username)value(?,?,?,?,?,?,?)";

       Object []obj={f.getId(),f.getUuidname(),f.getRealname(),f.getSavepath(),f.getUptime(),f.getDescription(),f.getUsername()};

       try {

           qr.update(sql,obj);

       } catch(SQLException e) {

           thrownew RuntimeException(e);

       }

      

    }

 

}

服务层的接口和实现类：

import java.util.List;

 

importwww.hbsi.domain.UploadFile;

 

public interfaceBusinessServiceDao {

      public voidinsert(UploadFile f);

     

      public UploadFilegetUploadFile(String id);

     

      publicList<UploadFile> getUploadFiles();

}

实现类：

publicclass BusinessServiceDaoImpl implements BusinessServiceDao{

   UploadFileDao ufd = new UploadFileDaoImpl();

    @Override

    public UploadFilegetUploadFile(String id) {

      

       returnufd.getUploadFile(id);

    }

 

    @Override

    publicList<UploadFile> getUploadFiles() {

      

       returnufd.getUploadFiles();

    }

    @Override

    publicvoid insert(UploadFile f) {

      ufd.insert(f); 

    }

}

DownLoadServlet类：

publicclass DownLoadServletextends HttpServlet {

 

    publicvoid doGet(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

       UploadFile fu;

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

       BusinessServiceDao bsd =new BusinessServiceDaoImpl();

       try{

           fu = bsd.getUploadFile(id);

            

        }catch(Exception e){

              request.setAttribute("message", "下载的资源不存在！");

              request.getRequestDispatcher("/WEB-INF/manager/message.jsp").forward(request, response);

              return;

        }

        

        String filename =fu.getSavepath()+fu.getRealname();

//     这句话必须得加且放在流关闭之前

           response.setHeader("content-disposition", "attachment;filename="+URLEncoder.encode(fu.getRealname(),"utf-8"));

 

        FileInputStream fis = new FileInputStream(newFile(filename));

        OutputStream os = response.getOutputStream();

        byte [] buf= newbyte[1024];

        int len=0;

        while((len=fis.read(buf))>0){

            os.write(buf, 0, len);

        }

        os.close();

        fis.close();

       

    }

    publicvoid doPost(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

       doGet(request, response);

    }

}

ShowAllUploadFiles类：

publicclass ShowAllUploadFilesextends HttpServlet {

 

    publicvoid doGet(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

         BusinessServiceDao bsd =new  BusinessServiceDaoImpl();

         List<UploadFile> list = bsd.getUploadFiles();

         request.setAttribute("list", list);

         request.getRequestDispatcher("/WEB-INF/manager/showfiles.jsp").forward(request, response);

    }

 

    publicvoid doPost(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

       doGet(request, response);

    }

 

}

UDJumpServlet类：

publicclass UDJumpServletextends HttpServlet {

 

    publicvoid doGet(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

        request.getRequestDispatcher("WEB-INF/manager/ud.jsp").forward(request, response);

    }

 

    publicvoid doPost(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

       doGet(request, response);

    }

 

}

UploadJumpServlet类：

publicclass UploadJumpServletextends HttpServlet {

 

    publicvoid doGet(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

        request.getRequestDispatcher("/WEB-INF/manager/upload.jsp").forward(request, response);

    }

 

    publicvoid doPost(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

       doGet(request, response);

    }

 

}

publicclass UploadServletextends HttpServlet {

 

    publicvoid doGet(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

       UploadFile uf=null;

        String rootPath=this.getServletContext().getRealPath("/WEB-INF/upload");

         try {

           uf = DBUpload.doUpload(request,rootPath,UploadFile.class);

         }catch (Exception e) {

           request.setAttribute("message", "文件上传失败！");

           request.getRequestDispatcher("/WEB-INF/manager/message.jsp").forward(request, response);

           e.printStackTrace();

           return;

       }

         try{

             BusinessServiceDao bsd = newBusinessServiceDaoImpl();

           bsd.insert(uf);

           request.setAttribute("message", "文件上传成功！");

         }catch(Exception e){

              request.setAttribute("message", "文件上传成功但保存失败！");

 

         }

           request.getRequestDispatcher("/WEB-INF/manager/message.jsp").forward(request,response );

 

    }

    publicvoid doPost(HttpServletRequest request, HttpServletResponseresponse)

           throwsServletException, IOException {

       doGet(request, response);

    }

}

工具类：

获取连接：

publicclass DBManager {

    staticComboPooledDataSource cpds;

    static {

        cpds= new ComboPooledDataSource("mysql");

    }

   

   publicstatic DataSource getDataSource(){

    returncpds;

   }

}

实现文件上传：

  publicclass DBUpload {

    publicstatic <T> UploadFile doUpload(HttpServletRequestrequest,String rootPath,Class<T>clazz) throwsException{

        UploadFile uf = (UploadFile) clazz.newInstance();

        DiskFileItemFactory factory=new DiskFileItemFactory();

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

         factory.setRepository(new File(tempPath));

        ServletFileUpload upload = new ServletFileUpload(factory);

        upload.setHeaderEncoding("utf-8");

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

         for(FileItem item:list){

            if(item.isFormField()){

               String filename = item.getFieldName();

               String filevalue = item.getString();

               BeanUtils.setProperty(uf, filename, filevalue);

            }else{

                  String filename =item.getName();

               String realname = filename.substring(filename.lastIndexOf("\\")+1);

               String uuidname = getUUID(realname);

               String savepath=getBranchFolders(realname,rootPath);

               uf.setRealname(realname);

               uf.setUuidname(uuidname);

               uf.setSavepath(savepath);

               uf.setId(UUID.randomUUID().toString());

               uf.setUptime(new Date());

               InputStream is = item.getInputStream();

               FileOutputStream fos = new FileOutputStream(newFile(savepath+realname));

               int len=0;

               byte buf [] = newbyte[1024];

               while((len=is.read(buf))>0){

                    fos.write(buf, 0, len);

               }

               fos.close();

               is.close();

               item.delete();

            }

         }

        

       return uf;

      

    }

 

    privatestatic String getBranchFolders(String realname, StringrootPath) {

       intf1=realname.hashCode()&4;

       intf2=(realname.hashCode()&4)>>4;

       String savePath=rootPath+"\\"+f1+"\\"+f2+"\\";

       File file = newFile(savePath);

       if(!file.exists()){

           file.mkdirs();

       }

       returnsavePath;

    }

 

    privatestatic String getUUID(String realname) {

       Stringext=realname.substring(realname.lastIndexOf(".")+1);

       return UUID.randomUUID().toString()+ext;

    }

}

Web层：

  index.jsp

<html>

 

   <frameset rows="20%,*">

    <frame name="head"  src="UDJumpServlet">

    <frame name="body" src="">

  </frameset>

</html>

message.jsp

<html>

  <body>

   ${message}

  </body>

</html>

showfiles.jsp

<html>

<body>

    

 

  <table border ="1px" width="50%" align="center">

     <CAPTION>文件下载区</CAPTION>

     <thead>

     <th>文件名</th>

     <th>上传者</th>

     <th>上传时间</th>

     <th>文件描述</th>

     <th>操作</th>

     </thead>

     <tbody>

        <c:forEach var ="file"items="${list}">

    <c:url var="url" value="DownLoadServlet">

               <c:param name="id"value="${file.id}"/>

   </c:url>  

       <tr><td>${file.realname}</td>

         <td>${file.username}</td>

         <td>${file.uptime}</td>

           <td>${file.description}</td>

           <td><a href = "${url}">下载</a></td>

           </tr>

            

             </c:forEach>

     </tbody>

  </table>

     

  </body>

</html>

ud.jsp

<html>

 <body>

   <h2 align="center">文件上传与下载</h2>

   <table align="center">

   <tr><td><a href="UploadJumpServlet" target="body">上传</a></td><td></td><td></td><td><a href="ShowAllUploadFiles" target="body">下载</a></td></tr>

   </table>

  </body>

</html>

upload.jsp

<html>

  <body >

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

    <table align="center" border="1px"  width="50%">

     <tr><td width="100px">上传者：</td><td><input type="text" name="username"/></td></tr>

     <tr><td width="100px">选择文件：</td><td><input type="file" name="file"/></td></tr>

     <tr><td width="100px">资源描述：</td><td><textarea cols="70" rows="5"name="description"></textarea></td></tr>

      <tr><td align="center" colspan="2"><input type="submit" value="上传"/></td></tr>

    </table>

    </form>

  </body>

</html>

好了，自己试试吧！