转载自  java图片格式转化（例如jpg格式转化png）

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转成PNGnew FormatConversion().Conversion(JPG,GIF,src);//JPG转成GIFnew FormatConversion().Conversion(JPG,BMP,src);//JPG转成BMP//其余格式转化只要调用Conversion函数即可}//inputFormat表示原格式，outputFormat表示转化后的格式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();}}}