java实现动态上传多个文件并解决文件重名问题(转)

Posted 2020-07-02 FreeCoder

本文分为两大方面进行讲解：

一、java实现动态上传多个文件

二、解决文件重命名问题java

供大家参考，具体内容如下

1、动态上传多个文件

<script>

<form name="xx" action="<c:url value=‘/Up3Servlet‘/>" method="post" enctype="multipart/form-data">

  <table id="tb" border="1">

    <tr>

      <td>

        File：

      </td>

      <td>

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

        <button onclick="_del(this);">删除</button>

      </td>

    </tr>

  </table>

  <br/>

  <input type="button" onclick="_submit();" value="上传">

  <input onclick="_add();" type="button" value="增加">

  </form>

 </body>

 <script type="text/javascript">

   function _add(){

     var tb = document.getElementById("tb");

     //写入一行

     var tr = tb.insertRow();

     //写入列

     var td = tr.insertCell();

      //写入数据

     td.innerhtml="File：";

     //再声明一个新的td

     var td2 = tr.insertCell();

     //写入一个input

     td2.innerHTML=‘<input type="file" name="file"/><button onclick="_del(this);">删除</button>‘;

   }

   function _del(btn){

     var tr = btn.parentNode.parentNode;

     //alert(tr.tagName);

     //获取tr在table中的下标

     var index = tr.rowIndex;

     //删除

     var tb = document.getElementById("tb");

     tb.deleteRow(index);

   }

   function _submit(){

     //遍历所的有文件

     var files = document.getElementsByName("file");

     if(files.length==0){

       alert("没有可以上传的文件");

       return false;

     }

     for(var i=0;i<files.length;i++){

       if(files[i].value==""){

         alert("第"+(i+1)+"个文件不能为空");

         return false;

       }

     }

    document.forms[‘xx‘].submit();

   }

 </script>

遍历所有要上传的文件

2、解决文件的重名的问题

 

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.ArrayList;

import java.util.List;

import java.util.UUID;

 

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import org.apache.commons.fileupload.FileItem;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

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

import org.apache.commons.io.FileUtils;

 

public class UpImgServlet extends HttpServlet {

 

  public void doPost(HttpServletRequest request, HttpServletResponse response)

      throws ServletException, IOException {

    request.setCharacterEncoding("UTF-8");

    String path = getServletContext().getRealPath("/up");

    DiskFileItemFactory disk =

        new DiskFileItemFactory(1024*10,new File("d:/a"));

    ServletFileUpload up = new ServletFileUpload(disk);

    try{

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

      //只接收图片*.jpg-iamge/jpege.,bmp/imge/bmp,png,

      List<String> imgs = new ArrayList<String>();

      for(FileItem file :list){

        if(file.getContentType().contains("image/")){

          String fileName = file.getName();

          fileName = fileName.substring(fileName.lastIndexOf("\\")+1);

           

          //获取扩展

          String extName = fileName.substring(fileName.lastIndexOf("."));//.jpg

          //UUID

          String uuid = UUID.randomUUID().toString().replace("-", "");

          //新名称

          String newName = uuid+extName;     //在这里用UUID来生成新的文件夹名字，这样就不会导致重名

           

           

          FileUtils.copyInputStreamToFile(file.getInputStream(),

              new File(path+"/"+newName));

          //放到list

          imgs.add(newName);

        }

        file.delete();

      }

      request.setAttribute("imgs",imgs);

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

    }catch(Exception e){

      e.printStackTrace();

    }

   

  }

 

}

以上实现了java多文件上传，解决了文件重名问题，希望对大家的学习有所帮助。