import java.io.*;
import java.awt.image.*;
import com.sun.image.codec.jpeg.*;
sourceFile:原文件地址;disFile:目的文件地址;
public boolean doZoom(int width,int height,String sourceFile,String disFile) throws Exception
{
File sourcefile=new File(sourceFile);
BufferedImage src=ImageIO.read(sourcefile);
BufferedImage image= new BufferedImage(width,height,BufferedImage.SCALE_SMOOTH);
image.getGraphics().drawImage(src,0,0,width,height,null);//绘制
File disfile=new File(disFile);
FileOutputStream fos=new FileOutputStream(disfile);//写入到流
JPEGImageEncoder sencoder = JPEGCodec.createJPEGEncoder(fos);
sencoder.encode(image);//写入jpg编码
fos.close();
return true;
}