java图片转换格式并设定大小

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
/**
 * 支持转换成BMP, JPG,PNG, JPEG, WBMP, GIF格式
 * 
 */
public class ImageConvertJPEG  {
    private String inPath;    //输入路径
    private String outPath;    //输出路径，不包含文件名，如C:\\Users\\Administrator\\Desktop或C:/Users/Administrator/Desktop
    private String outFileName; //输出文件名,如myPicture
    private int width=200;    //转换后的图片宽度
    private int heigth=200;    //轮换后的图片高度
    
    public void beginConvert() throws IOException {
    File inFile = new File(inPath);
    if (!inFile.exists() || inFile.isDirectory()) {
        throw new IOException("文件不存在！");
    }
    File outFile = new File(outPath + "/" + outFileName + ".jpeg");
    try {
        BufferedImage bufferedImage = ImageIO.read(inFile);
        BufferedImage bufferedChange=new BufferedImage(width, heigth, BufferedImage.TYPE_INT_BGR);
        Graphics2D g = (Graphics2D) bufferedChange.getGraphics();
        g.drawImage(bufferedImage, 0, 0, 256, 256, null);
        g.dispose();
        bufferedChange.flush();
        ImageIO.write(bufferedChange, "JPEG", outFile);
    } catch (Exception e) {
        throw new IOException("输入文件不是允许图片！");
    }
    }
    public ImageConvertJPEG() {
    }
    
    public ImageConvertJPEG(String inPath, String outPath, String outFileName) {
    this.inPath = inPath;
    this.outPath = outPath;
    this.outFileName = outFileName;
    }
}