import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Scanner;

import javax.imageio.*;
public class FormatConversion {
    public static final String JPG = "jpg";
    public static final String GIF = "gif";
    public static final String PNG = "png";
    public static final String BMP = "bmp";
    public static void main(String[] args) {
        String src = "E:/2.";
        new FormatConversion().Conversion(JPG,PNG,src);//JPG轉成PNG
        new FormatConversion().Conversion(JPG,GIF,src);//JPG轉成GIF
        new FormatConversion().Conversion(JPG,BMP,src);//JPG轉成BMP
        //其餘格式轉化只要呼叫Conversion函式即可
    }

    //inputFormat表示原格式，outputFormat表示轉化後的格式
    public void Conversion(String inputFormat,String outputFormat,String src){

        try {
            File input = new File(src+inputFormat);
            BufferedImage bim = ImageIO.read(input);
            File output = new File(src+outputFormat);
            ImageIO.write(bim, outputFormat, output);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}