画像重ね合わせ効果Javaコードの実現

import java.awt.AlphaComposite;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
public class NewImageUtils {
  /**
   * 
   * @Title:     
   * @Description:        java.awt.image.BufferedImage
   * @param file
   *         (  )
   * @param waterFile
   *          (  )
   * @param x
   *            X   
   * @param y
   *            Y   
   * @param alpha
   *         ,     0.0~1.0:     ~     
   * @return BufferedImage
   * @throws IOException
   */
  public static BufferedImage watermark(File file, File waterFile, int x, int y, float alpha) throws IOException {
    //     
    BufferedImage buffImg = ImageIO.read(file);
    //     
    BufferedImage waterImg = ImageIO.read(waterFile);
    //   Graphics2D  ，         
    Graphics2D g2d = buffImg.createGraphics();
    int waterImgWidth = waterImg.getWidth();//        
    int waterImgHeight = waterImg.getHeight();//        
    //                 
    g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));
    //   
    g2d.drawImage(waterImg, x, y, waterImgWidth, waterImgHeight, null);
    g2d.dispose();//               
    return buffImg;
  }

  /**
   *       
   * 
   * @param buffImg
   *              BufferedImage  
   * @param savePath
   *                  
   */
  private void generateWaterFile(BufferedImage buffImg, String savePath) {
    int temp = savePath.lastIndexOf(".") + 1;
    try {
      ImageIO.write(buffImg, savePath.substring(temp), new File(savePath));
    } catch (IOException e1) {
      e1.printStackTrace();
    }
  }

  /**
   * 
   * @param args
   * @throws IOException
   *       IO       
   * @author bls
   */
  public static void main(String[] args) throws IOException {
    String sourceFilePath = "D://img//di.png";
    String waterFilePath = "D://img//ceng.png";
    String saveFilePath = "D://img//new.png";
    NewImageUtils newImageUtils = new NewImageUtils();
    //      
    BufferedImage buffImg = NewImageUtils.watermark(new File(sourceFilePath), new File(waterFilePath), 0, 0, 1.0f);
    //       
    newImageUtils.generateWaterFile(buffImg, saveFilePath);
  }
}