Comment: Uploading multiple files may have been complicated to implement in the past, but since the emergence of html5, it has become very easy. There is a good example below, you can refer to it.
The main use is the multiple attribute of <input><input type="file" multiple />
Here is the detailed code of the page:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>Solution 4-5: Sending multiple files</title>
</head>
<body>
<form
action="http://10.10.25.31:8080/myupload/UploadPhotoServlet" ENCTYPE="multipart/form-data" METHOD="POST">
<input type="file" multiple /> <input
type="submit" value="submit"> <input type="reset" value="reset">
</form>
</body>
</html>
Detailed code of java background:
import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
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.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class UploadPhotoServlet
*/
public class UploadPhotoServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public UploadPhotoServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request,response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
@SuppressWarnings("unchecked")
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String imagePath="c://uploadFile//Image//"+getEachDate()+"//";// Generate folders by date
File uploadPath=new File(imagePath);
if(!uploadPath.exists()){
uploadPath.mkdirs();
}
File tmp=new File("c://tmp//");
if(!tmp.exists()){
tmp.mkdirs();
}
DiskFileItemFactory factory=new DiskFileItemFactory ();//Create a disk factory
factory.setRepository(tmp);//Set the file cache path
factory.setSizeThreshold(10 * 1096);//The default critical value of saving files in memory or temporary folders of disk is 10240, i.e. 10kb
ServletFileUpload sfu=new ServletFileUpload(factory);//Create processing tools
sfu.setSizeMax(10*1024*1024);//The maximum file size that can be received by the server, -1 means no upper limit
String fileName=null;
try {
List<FileItem> list=sfu.parseRequest(request);//Analysis
if(list.size()<1){
return;
}
for(int j=0;j<list.size();j++){
FileItem item=list.get(j);
fileName=item.getName();
if(fileName.equals("")){
request.getRequestDispatcher("/com/visualizerPhoto.jsp").forward(request, response);
return;
}
int pos=fileName.lastIndexOf(".");//Get the image file format
if(pos>0){
Date date=new Date();
fileName=imagePath+date.getTime()+fileName.substring(pos);
}
System.out.println("item:"+item);
item.write(new File(fileName));//Write to disk
}
} catch (FileUploadException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
// 13-11-15
public static String getEachDate() {
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 0);
String yesterday = new SimpleDateFormat("yyyy-MM-dd ").format(cal
.getTime());
String[] dates = yesterday.split("-");
String realDate = dates[0].substring(2, 4) + "-" + dates[1] + "-"
+ dates[2];
return realDate.trim();
}
}
Here is the rendering: