主要步骤如下:
import java.io.*;
import java.util.*;
import com.sun.image.codec.jpeg.*;
import java.awt.*;
import java.awt.geom.*;
import java.awt.image.*;OutputStream out=....;
BufferedImage image=new BufferedImage(150,100,BufferedImage.TYPE_INT_RGB);
Graphics2D g=(Graphics2D)image.getGraphics();
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
    
JPEGImageEncoder encoder=JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
out.close();