In this example, the jspsmart component is used for uploading. You can download this component www.jspsmart.com for free.
Download unzip, copy the jar package to \ WEB-INF \ lib directory and restart the server, jspsmart can be used normally
1. uploadimage. jsp
<% @ Page contentType = "text/html; charset = gb2312" language = "java" import = "java. io. *, java. awt. image, java. awt. image. *, com.sun.image.codec.jpeg. *, java. SQL. *, com. jspsmart. upload. *, java. util. *, cn. oof. database. *, cn. oof. house. * "%>
<%
SmartUpload mySmartUpload = new SmartUpload ();
Long file_size_max = 4000000;
String fileName2 = "", ext = "", testvar = "";
String url = "uploadfile/images/"; // ensure that this directory exists in the root directory
// Initialization
MySmartUpload. initialize (pageContext );
// Only files of this type can be uploaded
Try {
MySmartUpload. setAllowedFilesList ("jpg, gif ");
// Upload a file
MySmartUpload. upload ();
} Catch (Exception e ){
%>
<SCRIPT language = javascript>
Alert ("Upload only. jpg and. GIF image files allowed ");
Window. location = 'upfile. jsp ';
</Script>
<%
}
Try {
Com. jspsmart. upload. File myFile = mySmartUpload. getFiles (). getFile (0 );
If (myFile. isMissing () {%>
<SCRIPT language = javascript>
Alert ("select the file to upload first ");
Window. location = 'upfile. jsp ';
</Script>
<%}
Else {
// String myFileName = myFile. getFileName (); // get the name of the uploaded file
Ext = myFile. getFileExt (); // get the suffix
Int file_size = myFile. getSize (); // get the file size
String saveurl = "";
If (file_size <file_size_max ){
// Change the file name to obtain the millisecond value of the current upload time
Calendar calendar = Calendar. getInstance ();
String filename = String. valueOf (calendar. getTimeInMillis ());
Saveurl = request. getRealPath ("/") + url;
Saveurl + = filename + "." + ext; // save path
MyFile. saveAs (saveurl, mySmartUpload. SAVE_PHYSICAL );
// Out. print (filename );
// ----------------------- After the upload is complete, the thumbnail is generated -------------------------
Java. io. File file = new java. io. File (saveurl); // read the uploaded File
String newurl = request. getRealPath ("/") + url + filename + "_ min." + ext; // new thumbnail storage address
Image src = javax. imageio. ImageIO. read (file); // construct an Image object
Float tagsize = 200;
Int old_w = src. getWidth (null); // obtain the source image width.
Int old_h = src. getHeight (null );
Int new_w = 0;
Int new_h = 0; // obtain the source image length.
Int tempsize;
Float tempdouble;
If (old_w> old_h ){
Tempdouble = old_w/tagsize;
} Else {
Tempdouble = old_h/tagsize;
}
New_w = Math. round (old_w/tempdouble );
New_h = Math. round (old_h/tempdouble); // calculate the length and width of the new graph.
BufferedImage tag = new BufferedImage (new_w, new_h, BufferedImage. TYPE_INT_RGB );
Tag. getGraphics (). drawImage (src, new_w, new_h, null); // draw the reduced Graph
FileOutputStream newimage = new FileOutputStream (newurl); // output to the file stream
Required imageencoder encoder = required codec. createJPEGEncoder (newimage );
Encoder. encode (tag); // near JPEG encoding
Newimage. close ();
}
Else {
Out. print ("<SCRIPT language = 'javascript '> ");
Out. print ("alert ('the size of the uploaded file cannot exceed '+ (file_size_max/1000) +" K ');");
Out. print ("window. location = 'upfile. jsp ;'");
Out. print ("</SCRIPT> ");
}
}
} Catch (Exception e ){
E. toString ();
}
%>
2 upload.htm
<Html>
<Head>
<Title> select an uploaded image </title>
</Head>
<Body>
<Table border = "0" align = "center" cellpadding = "0" cellspacing = "0">
<Tr>
<Td height = "45" align = "center" valign = "middle"> <form action = "uploadimage. jsp "method =" post "enctype =" multipart/form-data "name =" form1 ">
Select the uploaded Image
<Input type = "file" name = "file">
<Input type = "submit" name = "Submit" value = "Upload">
</Form> </td>
</Tr>
</Table>
</Body>
</Html>
Author: "Li Changchun's blog"
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