java中图片处理问题

Question

我用java处理一个jpg图片，通过像素值在图片上画圆，画线等操作。总是不成功，代码如下
String filename= "D:\\map.jpg";
File file = new File("D:\\maptemp.jpg");
FileOutputStream out = new FileOutputStream(file);
//构造一个缓冲的图像。 
Image image = new ImageIcon(filename).getImage();
         //创建一个BufferedImage, 然后把导入的图片先画到这个BufferedImage. 
BufferedImage bufImage = new BufferedImage(image.getWidth(null), image.getHeight(null),  BufferedImage.TYPE_INT_RGB);
Graphics  imageGraphics =   bufImage.getGraphics();   
Point center = new Point(10,10);
Point start =new Point(0,0);
Point end = new Point(100,100);
imageGraphics.drawImage(image, 0,0,null);
         imageGraphics.fillOval((int) center.getX()-2, (int) center.getY()-2,10, 10);
imageGraphics.drawLine((int)start.getX(), (int)start.getY(), (int)end.getX(), (int)end.getY());
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); 
try {
encoder.encode(bufImage);
} catch (ImageFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}有谁能帮我解决一下，如果有其他方法，能给示例代码最好。急

Answer 1

import javax.swing.*;
import javax.imageio.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
import java.io.*;
public class TestDrawImage {
    JFrame frame;
    Container contentPane;
    JPanel pan;
    BufferedImage buffer;
    public TestDrawImage(){
        frame=new JFrame();
        contentPane=frame.getContentPane();
        try{
            buffer=ImageIO.read(new File("002.bmp"));
            Graphics g=buffer.getGraphics();
            g.setColor(Color.red);
            g.setFont(new Font("楷体",Font.PLAIN,40));
            g.drawString("哈哈，我改了", 50, 50);
            FileOutputStream fos=new FileOutputStream("new.bmp");
            ImageIO.write(buffer, "bmp", fos);
            fos.close();
        }catch(IOException e){}
        pan=new JPanel(){
            public void paint(Graphics g){
                if(buffer!=null){
                    g.drawImage(buffer, 0, 0, null);
                }
            }
        };
        contentPane.add(pan);
        if(buffer==null){
            frame.setSize(new Dimension(400,400));
        }else{
            frame.setSize(new Dimension(buffer.getWidth(),buffer.getHeight()));
        }
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
    public static void main(String args[]){
        new TestDrawImage();
    }
}