java中圖片格式轉換

package test;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import javax.imageio.ImageIO;

/**
 * 圖片基本操作
 */
public class ImageEncoderService {

    private static ImageEncoderService instance;

    private ImageEncoderService() {
        instance = this;
    }

    public static ImageEncoderService getInstance() {
        if (instance == null) {
            instance = new ImageEncoderService();
        }
        return instance;
    }

    /**
     * 縮小並轉換格式
     * 
     * @param srcPath源路徑
     * @param destPath目標路徑
     * @param height目標高
     * @param width
     *            目標寬
     * @param formate
     *            文件格式
     * @return
     */
    public boolean narrowAndFormateTransfer(String srcPath, String destPath, int height, int width, String formate) {
        boolean flag = false;
        try {
            File file = new File(srcPath);
            File destFile = new File(destPath);
            if (!destFile.getParentFile().exists()) {
                destFile.getParentFile().mkdir();
            }
            BufferedImage src = ImageIO.read(file); // 讀入文件
            Image image = src.getScaledInstance(width, height, Image.SCALE_DEFAULT);
            BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics g = tag.getGraphics();
            g.drawImage(image, 0, 0, null); // 繪製縮小後的圖
            g.dispose();
            flag = ImageIO.write(tag, formate, new FileOutputStream(destFile));// 輸出到文件流
        } catch (IOException e) {
            e.printStackTrace();
        }
        return flag;
    }

    public static void main(String[] args) {
        try {
            ImageEncoderService service = new ImageEncoderService();
            boolean flag = service.narrowAndFormateTransfer("E:\\我的圖片/雨傘.jpg", "E:\\我的圖片/雨傘.png", 400, 400, "png");
            System.out.println(flag);
        } catch (Exception e) {
            System.out.println(e);
        }
    }

}