Java method for uploading file images to server

Here I record a relatively simple and convenient JAVA to upload files and pictures to the server and save them, the specific content is as follows

First is the page html of me which is to submit 1 file and type

<div style="border: 1px solid red;"> 
   I am adding 1 It's a temporary picture that gets WeChat media_id Save database ! 
  <form action="xxxxxxxxm" 
  enctype="multipart/form-data" method="post"> 
  <div style="display: none;"> 
   <input type="text" value="IMAGE" name="type"/> 
  </div> 
   To upload pictures :<input type="file" name="file" 
   onchange="previewImage(this, 'prvid')" multiple="multiple"><br /> 
  <input type="submit" value=" submit " /> 
  </form> 
  <div id="prvid"> Preview the container </div> 
 </div> 

Preview image js

function previewImage(file, prvid) { 
 /* file : file controls  
 * prvid:  Picture preview container  
 */ 
 var tip = "Expect jpg or png or gif!"; //  Setting prompt message  
 var filters = { 
 "jpeg" : "/9j/4", 
 "gif" : "R0lGOD", 
 "png" : "iVBORw" 
 } 
 var prvbox = document.getElementById(prvid); 
 prvbox.innerHTML = ""; 
 if (window.FileReader) { // html5 plan  
 for (var i = 0, f; f = file.files[i]; i++) { 
  var fr = new FileReader(); 
  fr.onload = function(e) { 
  var src = e.target.result; 
  if (!validateImg(src)) { 
   alert(tip) 
  } else { 
   showPrvImg(src); 
  } 
  } 
  fr.readAsDataURL(f); 
 } 
 } else { //  down-cycled  
 
 if (!/\.jpg$|\.png$|\.gif$/i.test(file.value)) { 
  alert(tip); 
 } else { 
  showPrvImg(file.value); 
 } 
 } 
 
 function validateImg(data) { 
 var pos = data.indexOf(",") + 1; 
 for ( var e in filters) { 
  if (data.indexOf(filters[e]) === pos) { 
  return e; 
  } 
 } 
 return null; 
 } 
 
 function showPrvImg(src) { 
 var img = document.createElement("img"); 
 img.src = src; 
 prvbox.appendChild(img); 
 } 
} 

And then you get the background

@RequestMapping(params = "method=addCircle") 
public String addCircle(HttpServletResponse response,HttpServletRequest request) throws IOException { 
 request.setCharacterEncoding("utf-8"); 
 response.setContentType("text/html;charset=utf-8"); 
 
 
 String path = request.getSession().getServletContext().getRealPath( 
  "/BackstageShoppingWebsite/images/addCircleimage");// Saved server address  
 
 
 Map<String, String> map = Upload 
  .upload(request, 1024 * 1024 * 10, path); 
 
 
 String file= map.get("file"); //  The name of the  
 String image = map.get("type"); //  image  
 String newFile = map.get("newFile");//  address  
 
 return null; 
 } 

Ok, now the point is to look at the Upload class which is basically encapsulated, you can take whatever you need to add and modify it, and then this class uses the cos.jar package

package com.web.weixin.bean; 
import java.io.File; 
import java.io.IOException; 
import java.util.Date; 
import java.util.HashMap; 
import java.util.Map; 
import javax.servlet.http.HttpServletRequest; 
 
import com.oreilly.servlet.multipart.FilePart; 
import com.oreilly.servlet.multipart.MultipartParser; 
import com.oreilly.servlet.multipart.ParamPart; 
import com.oreilly.servlet.multipart.Part; 
 
 
public class Upload { 
 
 public static Map<String, String> upload(HttpServletRequest request, 
  int maxSize, String path) { 
  
 // In order to map Form saving data  key The corresponding save is on the get interface name The name of the  value Save is on the get screen name The value of the corresponding  
 Map<String, String> map = new HashMap<String, String>(); 
 Part part = null; 
 try { 
  MultipartParser mrequest = new MultipartParser(request, maxSize); 
  mrequest.setEncoding("utf-8"); 
  // I'm going through all of them part group  
  while ((part = mrequest.readNextPart()) != null) { 
  if (part.isFile()) { // Determine if it's a file  
 
   FilePart filepart = (FilePart) part;// Convert to file group  
 
   String fileName = filepart.getFileName();// Get the file name  
 
   if (fileName != null && fileName.length() > 0) { 
   //  Get the extension  
   String fileExtName = fileName.substring( 
    fileName.lastIndexOf(".") + 1).toLowerCase(); 
   //  Upload pictures only  // Determine if the image is uploaded in the right format   Whether the suffix name is valid  
   if (fileExtName.equalsIgnoreCase("jpeg") 
    || fileExtName.equalsIgnoreCase("png")|| 
    fileExtName.equalsIgnoreCase("jpg") 
    || fileExtName.equalsIgnoreCase("gif") 
    || fileExtName.equalsIgnoreCase("ico") 
    || fileExtName.equalsIgnoreCase("bmp") 
    || fileExtName.equalsIgnoreCase("flv") 
    || fileExtName.equalsIgnoreCase("mp4") 
    || fileExtName.equalsIgnoreCase("mp3")) { 
 
    
    /*String newFileName = new Date().getTime() + "."+ fileExtName;
    // Rename file   The file name + extension  */    
    
    String newFileName =new Date().getTime() +fileName;// Do not change the name of the picture  
    
    String newPath = path + "/" + newFileName; // File handles the path to file uploads  
    File newFile = new File(newPath); 
    
    filepart.writeTo(newFile); // Actually write the file to the corresponding folder  
    
    //filepart.getName()  get  request  The name of the parameter to receive  
    
    map.put(filepart.getName(), newFileName);// Save the file information to map In the  
    map.put("newFile", newFile.toString()); 
   } else { 
    map.put("geshi", "geshi"); 
    continue; 
   }//  This is not a picture  
   } else { 
 
   map.put("yes","yes"); 
 
   continue; //  Note that you did not choose to upload the image  
   } 
 
  } else if (part.isParam()) { // Determine if it is a parameter  
   ParamPart paramPart = (ParamPart) part; 
   map.put(paramPart.getName(), paramPart.getStringValue()); 
 
  } 
  } 
 
 } catch (IOException e) { 
  e.printStackTrace(); 
 } 
 return map; 
 } 
 
} 

To download the cos.jar package, click the open link

This article has been compiled in Java Upload operation Skills Summary, welcome to learn to read.