public static void main(String[] args) {
  
  //文件与BufferedImage间的转换
  BufferedImage bi=file2img("test.jpg");  //读取图片
  BufferedImage bii=img_color_brightness(bi,100);
  img2file(bii,"jpg","test1.jpg");  //生成图片
  
}

//图片色阶调整，调整rgb的分量
  public static BufferedImage img_color_brightness(BufferedImage imgsrc, int brightness) {
    try {
      //创建一个不带透明度的图片
      BufferedImage back=new BufferedImage(imgsrc.getWidth(), imgsrc.getHeight(),BufferedImage.TYPE_INT_RGB);
      int width = imgsrc.getWidth();  
          int height = imgsrc.getHeight();  
          for (int i = 0; i < height; i++) { 
            for (int j = 0; j < width; j++) {  
                  int pixel = imgsrc.getRGB(j, i); 
                  Color color = new Color(pixel);
                  int red= color.getRed()+brightness; if(red>255) red=255; if(red<0) red=0;
                  int green= color.getGreen()+brightness; if(green>255) green=255; if(green<0) green=0;
                  int blue= color.getBlue()+brightness; if(blue>255) blue=255; if(blue<0) blue=0;
                  color = new Color(red,green,blue);
                  int x=color.getRGB();
                  back.setRGB(j,i,x);
              }
          }
      return back;
    } catch (Exception e) {
      e.printStackTrace();
      return null;
    }
  }

//读取图片
  public static BufferedImage file2img(String imgpath) {
    try {
      BufferedImage bufferedImage=ImageIO.read(new File(imgpath));
      return bufferedImage;
    } catch (Exception e) {
      e.printStackTrace();
      return null;
    }
  }
  //保存图片,extent为格式，"jpg"、"png"等
  public static void img2file(BufferedImage img,String extent,String newfile) {
    try {
      ImageIO.write(img, extent, new File(newfile));
    } catch (Exception e) {
      e.printStackTrace();
    }
  }