chart4.jsp

一本jsp自学教材

<%@ page contentType="image/jpeg;charset=GBK" %>
<%@ page import="com.sun.image.codec.jpeg.*"%>
<%@ page import="java.awt.image.*"%>
<%@ page import="java.awt.*"%>
<%@ page import="java.io.*"%>
<%@ page import="javax.servlet.*"%>
<%
File file = new File("C:/chart.jpg"); 
String newurl="C:/chart2.jpg";  //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); 
ServletOutputStream newimage=response.getOutputStream(); 
        //输出到文件流
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(newimage);       
encoder.encode(tag);                                               //近JPEG编码
newimage.close();   
%>
 
 //JPEGImageEncoder encoder=JPEGCodec.createJPEGEncoder(sos); 
  //encoder.encode(image);     
/*byte[] buffer = new byte[1024];
int len=0;
while((len=is.read(buffer))>0){
  sos.write(buffer,0,len); 
}  
  sos.flush();      
  sos.close(); */