jsp上傳圖片

2024-09-05 00:19:14

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jsp上傳圖片并生成縮略圖

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-inflib　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>