javaweb implementation file upload sample code

  • 2020-06-19 10:25:45
  • OfStack

This article examples for you to share javaweb file download specific implementation code, for your reference, the specific content is as follows

Sample file upload

Note: The jsp page is encoded as "ES7en-8"

Requirements for file uploads

1.form form, which must be submitted in POST mode

2.enctype="multipart/form-data"

3. There must be < input type="file" / >

Front end jsp page


<%@ 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%>" rel="external nofollow" >
 
 <title>My JSP 'index.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" rel="external nofollow" >
 -->
 </head>
 <script type="text/javascript">
  function addFile(){
   var div1=document.getElementById("div1");
   div1.innerHTML+="<div><input type='file' /><input type='button' value=' delete ' onclick='deleteFile(this)' /> <br/></div>";
  
  }
  function deleteFile(div){
   // His grandfather deleted his father 
   div.parentNode.parentNode.removeChild(div.parentNode);
  
  }
 </script>
 <body>
  <form action="${pageContext.request.contextPath }/servlet/upLoadServlet" method="post" enctype="multipart/form-data">
   Description of the document: <input type="text" name ="description" /><br/>
  <div id="div1">
   <div>
   <input type="file" name ="file" /><input type="button" value=" add " onclick="addFile()" /><br/>
   </div>   
  </div> 
   <input type="submit" />
  </form>
 </body>
</html>

servlet for file upload


package com.learning.servlet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.UUID;

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 org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FilenameUtils;

/**
 * Servlet implementation class UpLoadServlet
 */
@WebServlet("/servlet/upLoadServlet")
public class UpLoadServlet extends HttpServlet {
 private static final long serialVersionUID = 1L;

 /**
  * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
  */
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  doGet(request, response);
 }

 /**
  * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
  */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   
  
  // File upload 
  // Determine whether file uploads are supported 
  boolean isMultipartContent = ServletFileUpload
    .isMultipartContent(request);
  if (!isMultipartContent) {
   throw new RuntimeException(" Does not support ");
  }
  
  //  create 1 a DiskFileItemfactory The factory class 
  DiskFileItemFactory diskFileItemFactory=new DiskFileItemFactory();
  //  create 1 a ServletFileUpload Core object 
  ServletFileUpload fileUpload=new ServletFileUpload(diskFileItemFactory);
  // Set Chinese scrambling code 
  fileUpload.setHeaderEncoding("UTF-8");
  // Set up the 1 File size per file 
  fileUpload.setFileSizeMax(1024*1024*3); // Size of the 3M
  // Sets the total file size 
  //fileUpload.setSizeMax(1024*1024*10);// Size of the 10M
  
  try {
   //fileload parsing request Request, return list<FileItem> A collection of 
   List<FileItem> fileItems = fileUpload.parseRequest(request);
   for (FileItem fileItem : fileItems) {
    if (fileItem.isFormField()) {
     // Is a text field  ( Functions that handle text fields )
     processFormField(fileItem);
    }else {
     // File domain  ( Functions that handle file fields )
     processUpLoadField1(fileItem);
    }
   }
   
  } catch (FileUploadException e) {
   e.printStackTrace();
  }
  
  
 }

 /**
  * @param fileItem
  * 
  */
 private void processUpLoadField1(FileItem fileItem) {
  
  try {
   // Gets the file read stream 
   InputStream inputStream = fileItem.getInputStream();
   
   // Get the file name 
   String fileName = fileItem.getName();
   
   // File name processing 
   if (fileName!=null) {
    fileName.substring(fileName.lastIndexOf(File.separator)+1);
    
   }else {
    throw new RuntimeException(" File name does not exist ");
   }
   
   // Repeat processing for filenames 
//   fileName=new String(fileName.getBytes("ISO-8859-1"),"UTF-8");
   fileName=UUID.randomUUID()+"_"+fileName;
   
   // Date of classification 
   SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd");
   String date = simpleDateFormat.format(new Date());
   // Create a directory 
   File parent=new File(this.getServletContext().getRealPath("/WEB-INF/upload/"+date));
   if (!parent.exists()) {
    parent.mkdirs();
   }
   
   // Upload a file 
   fileItem.write(new File(parent, fileName));
   // Delete temporary files (if the upload file is too large, it will be generated .tmp Temporary documents) 
   fileItem.delete();
   
  } catch (IOException e) {
   System.out.println(" Upload failed ");
   e.printStackTrace();
  } catch (Exception e) {
   
  }
  
  
  
 }

 /**
  * @param fileItem
  */
 // File domain 
 private void processUpLoadField(FileItem fileItem) {
   
  try {
   // Gets the file input stream 
   InputStream inputStream = fileItem.getInputStream();
   
   // Get is the name of the file 
   String filename = fileItem.getName();
   // Handle file names 
   if (filename!=null) {
//    filename.substring(filename.lastIndexOf(File.separator)+1);
    filename = FilenameUtils.getName(filename);
   }
   
   // Get the path and create a directory to hold the files 
   String realPath = this.getServletContext().getRealPath("/WEB-INF/load");
   
   File storeDirectory=new File(realPath);// It represents both a file and a directory 
   // Create the specified directory 
   if (!storeDirectory.exists()) {
    storeDirectory.mkdirs();
   }
   // Prevent filename 1 sample 
   filename=UUID.randomUUID()+"_"+filename;
   // Directory break up   To prevent the same 1 There are too many files under the directory file to find easily 
   
   // Store uploaded files by date 
   //storeDirectory = makeChildDirectory(storeDirectory);
   
   // Multiple directories hold uploaded files 
   storeDirectory = makeChildDirectory(storeDirectory,filename);
   
   FileOutputStream fileOutputStream=new FileOutputStream(new File(storeDirectory, filename));
   // Reads the file and outputs it to the specified directory 
   int len=1;
   byte[] b=new byte[1024];
   while((len=inputStream.read(b))!=-1){
    fileOutputStream.write(b, 0, len);
   }
   // Close the stream 
   fileOutputStream.close();
   inputStream.close(); 
   
  } catch (IOException e) {
   e.printStackTrace();
  } 
 }
 // Sort by date 
 private File makeChildDirectory(File storeDirectory) {
  SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd");
  String date = simpleDateFormat.format(new Date());
  // Create a directory 
  File childDirectory=new File(storeDirectory, date);
  if (!childDirectory.exists()) {
   childDirectory.mkdirs();
  }
  return childDirectory;
 } 
 // Multi-level directory 
 private File makeChildDirectory(File storeDirectory, String filename) {
  filename=filename.replaceAll("-", ""); 
  File childDirectory =new File(storeDirectory, filename.charAt(0)+File.separator+filename.charAt(1));
  if (!childDirectory.exists()) {
   childDirectory.mkdirs();  
  }
  return childDirectory;
 }
 // Text field 
 private void processFormField(FileItem fileItem) {
  // For the text field of Chinese gibberish, can be used new String() Way to solve 
   try {
    String fieldName = fileItem.getFieldName();// Field names in the form name , such as description
    String fieldValue = fileItem.getString("UTF-8");//description In the value
//    fieldValue=new String(fieldValue.getBytes("ISO-8859-1"),"UTF-8");
    System.out.println(fieldName +":"+fieldValue);
   } catch (UnsupportedEncodingException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   
 }

}

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