jsp上传图片

2024-09-05 00:19:14

字体：大中小

来源：转载

供稿：网友

jsp上传图片并生成缩略图

本例子使用了jspsmart组件进行上传，这里可以免费下载该组件www.jspsmart.com
下载解压后，将jar包复制到　web-inflib　目录后重启服务器，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/"; //应保证在根目录中有此目录的存在
//初始化
mysmartupload.initialize(pagecontext);
//只允许上载此类文件
try ...{
mysmartupload.setallowedfileslist("jpg,gif");
//上载文件
mysmartupload.upload();
} catch (exception e)...{
%>
<script language=javascript>
alert("只允许上传.jpg和.gif类型图片文件");
window.location='upfile.jsp';
</script>
<%
}
try...{

    com.jspsmart.upload.file myfile = mysmartupload.getfiles().getfile(0);
    if (myfile.ismissing())...{%>
   <script language=javascript>
   alert("请先选择要上传的文件");
   window.location='upfile.jsp';
   </script>
    <%}
    else...{
      //string myfilename=myfile.getfilename(); //取得上载的文件的文件名
   ext= myfile.getfileext();      //取得后缀名
   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，取得当前上传时间的毫秒数值
    calendar calendar = calendar.getinstance();
    string filename = string.valueof(calendar.gettimeinmillis());
    saveurl=request.getrealpath("/")+url;
    saveurl+=filename+"."+ext;          //保存路径
    myfile.saveas(saveurl,mysmartupload.save_physical);
    //out.print(filename);
//-----------------------上传完成，开始生成缩略图-------------------------
    java.io.file file = new java.io.file(saveurl);        //读入刚才上传的文件
    string newurl=request.getrealpath("/")+url+filename+"_min."+ext; //新的缩略图保存地址
    image src = javax.imageio.imageio.read(file);                     //构造image对象
    float tagsize=200;
    int old_w=src.getwidth(null);                                     //得到源图宽
    int old_h=src.getheight(null);
    int new_w=0;
    int new_h=0;                            //得到源图长
    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);//计算新图长宽
    bufferedimage tag = new bufferedimage(new_w,new_h,bufferedimage.type_int_rgb);
    tag.getgraphics().drawimage(src,0,0,new_w,new_h,null);       //绘制缩小后的图
    fileoutputstream newimage=new fileoutputstream(newurl);          //输出到文件流
    jpegimageencoder encoder = jpegcodec.createjpegencoder(newimage);
    encoder.encode(tag);                                               //近jpeg编码
     newimage.close();

   }
   else...{
    out.print("<script language='javascript'>");
    out.print("alert('上传文件大小不能超过"+(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>请选择上传的图片</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">
请选择上传的图片
    <input type="file" name="file">
<input type="submit" name="submit" value="上传">
    </form></td>
</tr>
</table>
</body>
</html>