Java servlet-based file asynchronous upload _java

Here using a servlet-based file asynchronous upload, good nonsense not much to say, directly on the code ...

Package com.future.zfs.util;
Import Java.io.File;
Import java.io.IOException;
Import Java.io.PrintWriter;
Import Java.util.Iterator;

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.FileUploadBase.SizeLimitExceededException;
Import Org.apache.commons.fileupload.disk.DiskFileItemFactory;

Import Org.apache.commons.fileupload.servlet.ServletFileUpload; @SuppressWarnings ("Serial") public class Fileuploadservlet extends HttpServlet {final long max_size = 10 * 1024 * 1024 //Set Upload file maximum 10M//Allow uploaded file format list final string[] Allowtype = new string[] {"JPG", "JPEG", "gif", "TXT", "Doc", "Docx", "MP3"

  , "WMA", "M4A", "xls"};
  Public Fileuploadservlet () {super (); public void Destroy () {SUPER.DESTROy (); @Override protected void Service (HttpServletRequest request, httpservletresponse response) throws Servletexce
    Ption, IOException {response.setcontenttype ("text/html");

    Set character encoding to UTF-8, which supports Chinese character display response.setcharacterencoding ("UTF-8");
    Instantiate a hard disk file factory to configure the upload component Servletfileupload diskfileitemfactory dfif = new Diskfileitemfactory (); Dfif.setsizethreshold (4096)//Set the amount of memory used to temporarily store files when uploading files, this is 4K. More than one part will temporarily have the hard drive dfif.setrepository new file ( Request.getrealpath ("/") + "Uploadtemp"))/set the directory where temporary files are stored, the Uploadtemp directory under the Web root directory//The upload component is instantiated with the above factory Servletfileu
    Pload SFU = new Servletfileupload (DFIF);

    Set Maximum upload size Sfu.setsizemax (max_size);
    PrintWriter out = Response.getwriter ();
    From request to get all the uploaded domain list filelist = null;
    try {filelist = sfu.parserequest (request); The catch (Fileuploadexception e) {//processing file size is too large an exception if (e instanceof sizelimitexceededexception) {out.println ("{ Message: ' File size exceeds the specified size: ' +max_size+ ' wordSection '} ');
      Return
    } e.printstacktrace ();
      //No file upload if (filelist = null | | filelist.size () = 0) {out.println ("{message: ' Select Upload file '}");
    Return
    //Get all uploaded files iterator Fileitr = Filelist.iterator ();
      Loops All Files while (Fileitr.hasnext ()) {Fileitem fileitem = null;
      String path = null;
      Long size = 0;
      Get current File Fileitem = (Fileitem) fileitr.next (); Ignore the simple form field instead of the File field (<input type= "text"/>) of the upload domain if (fileitem = = NULL | | Fileitem.isformfield ()) {cont
      Inue;
      //Get the full path of the file: Path = Fileitem.getname ();
      Get the size of the file = Fileitem.getsize (); if ("". Equals (path) | |
        Size = = 0) {out.println ("{message: ' Please select Upload file '}");
      Return
      ///Gets the filename of the removal path String t_name = path.substring (Path.lastindexof ("\") + 1);
      Gets the file's extension (will get full name without extension) String T_ext = t_name.substring (T_name.lastindexof (".") + 1); Refusal to accept the prescribed file formatThe file type int allowflag = 0;
      int allowedextcount = Allowtype.length;
      for (; Allowflag < Allowedextcount, allowflag++) {if (Allowtype[allowflag].equals (T_ext)) break;
        } if (Allowflag = = allowedextcount) {String message = ' ";
                        for (Allowflag = 0; Allowflag < Allowedextcount; allowflag++) {message+= "*." + Allowtype[allowflag]
        + " ";
        } out.println ("{message: ' Please upload the following type of file" +message+ "}");
      Return
      Long now = System.currenttimemillis ();
      Build the file name saved after uploading based on system time String prefix = string.valueof (now); The complete path to the saved final file, saved in the upload directory under the Web root directory String u_name = Request.getrealpath ("/") + "upload/" + prefix + "." +
      T_ext;
      The original filename path=request.getrealpath ("/") + "upload/" +path;
        try {//Save files Fileitem.write (new file (path));
        Response.setstatus (200); Out.println ("{message:\" file uploaded successfully.) Saved as: "+ prefIX + "." + t_ext + "File size:" + size + "byte \"} ";
      catch (Exception e) {e.printstacktrace ();
 }

    }
  }
}

Xml

<servlet>
    <servlet-name>fileUploadServlet</servlet-name>
    <servlet-class> com.future.zfs.util.fileuploadservlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>fileUploadServlet</servlet-name>
    <url-pattern>/fileuploadservlet</ Url-pattern>
  </servlet-mapping>

Upload page

<%@ page language= "java" contenttype= "text/html; Charset=utf-8 "pageencoding=" UTF-8 "%> <! DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "Http://www.w3.org/TR/html4/loose.dtd" >  

Note that you need to set the Response.setcontenttype ("text/html") when using ajaxfileupload based on the servlet upload; datatype: ' JSON ' is set to JSON still set Response.setcontenttype (' text/html '), otherwise the data returned by the server side is not obtained and a dialog box pops up.

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