本例子使用了jspsmart組件進行上傳，這里可以免費下載該組件www.jspsmart.com
下載解壓后，將jar包復制到 \WEB-INF\lib 目錄后重啟服務器，jspsmart即可正常使用了
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/";?????? //應保證在根目錄中有此目錄的存在
//初始化
mySmartUpload.initialize(pageContext);
//只允許上載此類文件
try {
mySmartUpload.setAllowedFilesList("jpg,gif");
//上載文件
mySmartUpload.upload();
} catch (Exception e){
%>
?? <SCRIPT language=javascript>
?? alert("只允許上傳.jpg和.gif類型圖片文件");
?? window.location=''upfile.jsp'';
?? </script>
<%
}
try{
???? com.jspsmart.upload.File myFile = mySmartUpload.getFiles().getFile(0);
???? if (myFile.isMissing()){%>
??? <SCRIPT language=javascript>
??? alert("請先選擇要上傳的文件");
??? window.location=''upfile.jsp'';
??? </script>
???? <%}
???? else{
?????? //String myFileName=myFile.getFileName(); //取得上載的文件的文件名
??? ext= myFile.getFileExt();?????? //取得后綴名
??? int file_size=myFile.getSize();????? //取得文件的大小??
??? String saveurl="";
??? if(file_size<file_size_max){
???? //更改文件名，取得當前上傳時間的毫秒數值
???? Calendar calendar = Calendar.getInstance();
???? String filename = String.valueOf(calendar.getTimeInMillis());
???? saveurl=request.getRealPath("/")+url;
???? saveurl+=filename+"."+ext;?????????? //保存路徑
???? myFile.saveAs(saveurl,mySmartUpload.SAVE_PHYSICAL);
???? //out.print(filename);
//-----------------------上傳完成，開始生成縮略圖-------------------------????
???? java.io.File file = new java.io.File(saveurl);???????? //讀入剛才上傳的文件
???? String newurl=request.getRealPath("/")+url+filename+"_min."+ext;?? //新的縮略圖保存地址
???? Image src = javax.imageio.ImageIO.read(file);????????????????????? //構造Image對象
???? float tagsize=200;
???? int old_w=src.getWidth(null);????????????????????????????????????? //得到源圖寬
???? int old_h=src.getHeight(null);???
???? int new_w=0;
???? int new_h=0;???????????????????????????? //得到源圖長
???? 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);//計算新圖長寬
???? BufferedImage tag = new BufferedImage(new_w,new_h,BufferedImage.TYPE_INT_RGB);
???? tag.getGraphics().drawImage(src,0,0,new_w,new_h,null);??????? //繪制縮小后的圖
???? FileOutputStream newimage=new FileOutputStream(newurl);?????????? //輸出到文件流
???? JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(newimage);???????
???? encoder.encode(tag);??????????????????????????????????????????????? //近JPEG編碼
????? newimage.close();????
??? }
??? else{
???? out.print("<SCRIPT language=''javascript''>");
???? out.print("alert(''上傳文件大小不能超過"+(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>請選擇上傳的圖片</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">
請選擇上傳的圖片
???? <input type="file" name="file">
<input type="submit" name="Submit" value="上傳">
???? </form></td>
?? </tr>
</table>
</body>
</html>