Apache commons-fileupload implements file upload and download

Package com. handson. bbs. servlet;

 

Import java. Io. file;

Import java. Io. ioexception;

Import java. util. date;

Import java. util. List;

Import javax. servlet. servletexception;

Import javax. servlet. http. httpservlet;

Import javax. servlet. http. httpservletrequest;

Importjavax. servlet. http. httpservletresponse;

Import javax. servlet. http. httpsession;

Importorg. Apache. commons. fileupload. fileitem;

Importorg. Apache. commons. fileupload. disk. diskfileitemfactory;

Importorg. Apache. commons. fileupload. servlet. servletfileupload;

Import com. handson. bbs. Bo. userbo;

Import com. handson. bbs. model. user;

/***//**

**************************************** *******

* @ Description file upload

* For this project, upload images in uploadfile/Image

* Cache directory c: \ TMP \

* After the photo is uploaded, the subsequent code is processed to update the user's photo in a timely manner.

* @ Author Gavin. Lee

* @ Date 2009-6-13 21:35:47

* @ Version 1.0

**************************************** *******

*/

Public class uploadphotoservlet extendshttpservlet {

Public void doget (httpservletrequest request, httpservletresponseresponse)

Throws servletexception, ioexception {

This. dopost (request, response );

}

 

Public void dopost (httpservletrequest request, httpservletresponseresponse)

Throws servletexception, ioexception {

String filepath = This. getservletcontext (). getrealpath ("/uploadfile/image/"); // container relative path

File TMP = new file ("C: \ TMP \\");

If (! TMP. exists ()){

TMP. mkdirs ();

}

Diskfileitemfactory factory = new diskfileitemfactory (); // create a disk Factory

Factory. setrepository (TMP); // File Cache path

Factory. setsizethreshold (1096x10 );

Servletfileupload SFU = new servletfileupload (factory); // create a processing tool

SFU. setsizemax (10*1024*1024); // The maximum file size that the server can receive.-1 indicates no upper limit.

String filename = NULL;

Try {

List <fileitem> List = SFU. parserequest (request); // parse

Fileitem item = list. Get (0 );

Filename = item. getname ();

If (filename. Equals ("")){

Request. getrequestdispatcher ("/COM/visualizephoto. jsp"). Forward (request, response );

Return;

}

Int Pos = filename. lastindexof ("."); // retrieves the image file format

If (Pos> 0 ){

Date = new date ();

Filename = filepath + '/' + date. gettime () + filename. substring (POS );

}

Item. Write (new file (filename); // write to disk

} Catch (exception e ){

E. printstacktrace ();

}

// If the object is uploaded only, you do not need to check the subsequent code. The latter is to update user information (photos) in a timely manner)

Httpsession session = request. getsession ();

User user = (User) Session. getattribute ("user ");

Int Pos = filename. indexof ("uploadfile"); // sets the relative path of the image.

If (Pos> 0 ){

Filename = filename. substring (Pos, POS + 10) + '/' + filename. substring (Pos + 11 );

}

User. setphoto (filename );

Userbo = userbo. getinstance ();

If (userbo. updateuser (User )){

Session. setattribute ("user", user );

Request. getrequestdispatcher ("/COM/visualizephoto. jsp"). Forward (request, response );

}

}

 

}

 

[Download]

Download seems simpler. packagecom. Gavin. Tools. fileupload;

 

Import java. Io. file;

Import java. Io. fileinputstream;

Import java. Io. ioexception;

Import java. Io. inputstream;

Import java. Io. printwriter;

 

Import javax. servlet. servletconfig;

Import javax. servlet. servletexception;

Import javax. servlet. http. httpservlet;

Importjavax. servlet. http. httpservletrequest;

Importjavax. servlet. http. httpservletresponse;

 

Public class filedownloadservlet extendshttpservlet {

 

Public void dopost (httpservletrequest request, httpservletresponseresponse)

Throws servletexception {

String filename = request. getparameter ("file_name ");

If (filename = NULL)

Filename = "";

Filename = filename. Trim ();

 

Inputstream instream = NULL;

String attchname = "";

 

Byte [] B = new byte [100];

Int Len = 0;

Try {

Attchname = getattachname (filename); // get the attachment name

Filename = getrealname (request, filename); // obtain the full path of the Attachment

If (filename = NULL ){

System. Out. println ("the file does not exist or cannot be downloaded ");

Return;

}

Attchname = toutf8string (attchname); // transcode the file UTF-8

Instream = new fileinputstream (filename );

Response. Reset (); // The Reset is required; otherwise, the file is incomplete.

Response. setcontenttype ("application/X-msdownload ");

Response. addheader ("content-disposition", "attachment; filename = \" "+ attchname + "\"");

// Cyclically retrieve the data in the stream

While (LEN = instream. Read (B)> 0 ){

Response. getoutputstream (). Write (B, 0, Len );

}

Instream. Close ();

} Catch (exception e ){

E. printstacktrace ();

}

}

 

// Obtain the attachment name

Public static string getattachname (string filename ){

If (filename = NULL)

Return "";

Filename = filename. Trim ();

Int Pos = 0;

Pos = filename. lastindexof ("\\");

If (Pos>-1 ){

Filename = filename. substring (Pos + 1 );

}

Pos = filename. lastindexof ("/");

If (Pos>-1 ){

Filename = filename. substring (Pos + 1 );

}

Pos = filename. lastindexof (file. separator );

If (Pos>-1 ){

Filename = filename. substring (Pos + 1 );

}

Return filename;

}

 

// Utf8 Transcoding

Public static string toutf8string (string ){

Stringbuffer sb = new stringbuffer ();

For (INT I = 0; I <string. Length (); I ++ ){

Char c = string. charat (I );

If (C> = 0 & C <= 255 ){

SB. append (C );

} Else {

Byte [] B;

Try {

B = character. tostring (c). getbytes ("UTF-8 ");

} Catch (exception ex ){

System. Out. println (Ex );

B = new byte [0];

}

For (Int J = 0; j <B. length; j ++ ){

Int K = B [J];

If (k <0)

K + = 256;

SB. append ("%" + integer. tohexstring (k). touppercase ());

}

}

}

String s_utf8 = sb. tostring ();

SB. Delete (0, SB. Length ());

SB. setlength (0 );

SB = NULL;

Return s_utf8;

}

 

// Obtain the real full path name of the downloaded object

Private string getrealname (httpservletrequest request, string filename ){

If (request = NULL | filename = NULL)

Return NULL;

Filename = filename. Trim ();

If (filename. Equals (""))

Return NULL;

 

String filepath = request. getrealpath (filename );

If (filepath = NULL)

Return NULL;

File file = new file (filepath );

If (! File. exists ())

Return NULL;

Return filepath;

}

 

Public void doget (httpservletrequest request, httpservletresponseresponse)

Throws servletexception {

This. dopost (request, response );

}

 

}