jsp中生成图片缩略图的代码

<%@ page contentType="text/html;charset=gb2312" %>

<%@ page language="java" import="java.util.*" %>

<%@ page language="java" import="java.io.*" %>

<%@ page language="java" import="java.awt.*" %>

<%@ page language="java" import="java.awt.image.*" %>

<%@ page language="java" import="com.sun.image.codec.jpeg.*" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<head>

</head>

<body>

response.setContentType("text/html;charset=gb2312");

request.setCharacterEncoding("gb2312");

out.print("==================Test for thumbtail picture=============");

//-----------------------上传完成，开始生成缩略图-------------------------

java.io.File file = new java.io.File("E:\\1110168154_58348.jpg");//saveurl); //读入刚才上传的文件

String newurl="E:\\1110168154_58348_min.jpg";//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=287;

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;

out.print("<br/>the old width is :"+old_w+" the old height is "+old_h+"<br/>");

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

out.print("the new width is :"+new_w+" the new height is "+new_h+"<br/>");

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();

</body>

</html>