JAVA 图片png和jpeg格式的转化方式

最近遇到一些需求，需要对图片做格式转化，比如将png图片转为jpeg，或者将jpeg转为png，网上有部分代码，但是发现有些是不正确的，

毕竟png是4通道，32位，而jpeg是3通道，24位，因此两个图片之间转化时，肯定需要注意这些问题，而不是简单的图片内容的转化。

下面小编是小编亲测实用的java方法：

public class ImageConvert {

    private static final String IMAGE_PATH_PNG = "F:\Gis开发\学习资料\tile\3_0_1.png";
    private static final String IMAGE_PATH_PNG_NEW = "F:\Gis开发\学习资料\tile\3_0_1_new.png";
    private static final String IMAGE_PATH_JPEG = "F:\Gis开发\学习资料\tile\3_0_1.jpg";
    private static final String IMAGE_PATH_JPEG_NEW = "F:\Gis开发\学习资料\tile\3_0_1_new.jpg";

    public static void main(String[] args) {
        png2jpeg();
    }

    public static void png2jpeg() {
        //读取图片
        FileOutputStream fos =null;
        try {
            BufferedImage bufferedImage = ImageIO.read(new File(IMAGE_PATH_PNG));
            //转成jpeg、
            BufferedImage bufferedImage1 = new BufferedImage(bufferedImage.getWidth(),
                                                             bufferedImage.getHeight(),
                                                             BufferedImage.TYPE_INT_RGB);
            bufferedImage1.createGraphics().drawImage(bufferedImage,0,0, Color.white,null);
            fos = new FileOutputStream(IMAGE_PATH_JPEG_NEW);
            ImageIO.write(bufferedImage,"jpg",fos);
            fos.flush();
        } catch (IOException e) {
            e.printStackTrace();
            try {
                fos.close();
            } catch (IOException ioException) {
                ioException.printStackTrace();
            }
        }
    }

    public static void jpeg2png() {
        //读取图片
        try {
            BufferedImage bufferedImage = ImageIO.read(new File(IMAGE_PATH_JPEG));
            //转成png、
            BufferedImage bufferedImage1 = new BufferedImage(bufferedImage.getWidth(),
                                                            bufferedImage.getHeight(),
                                                            BufferedImage.TYPE_INT_ARGB);
            bufferedImage1.createGraphics().drawImage(bufferedImage,0,0, Color.white,null);
            FileOutputStream fos = new FileOutputStream(IMAGE_PATH_PNG_NEW);
            ImageIO.write(bufferedImage1,"png",fos);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}