图片叠加效果Java代码实现

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: 构造图片
   * @Description: 生成水印并返回java.awt.image.BufferedImage
   * @param file
   *      源文件(图片)
   * @param waterFile
   *      水印文件(图片)
   * @param x
   *      距离右下角的X偏移量
   * @param y
   *      距离右下角的Y偏移量
   * @param alpha
   *      透明度, 选择值从0.0~1.0: 完全透明~完全不透明
   * @return BufferedImage
   * @throws IOException
   */
  public static BufferedImage watermark(File file, File waterFile, int x, int y, float alpha) throws IOException {
    // 获取底图
    BufferedImage buffImg = ImageIO.read(file);
    // 获取层图
    BufferedImage waterImg = ImageIO.read(waterFile);
    // 创建Graphics2D对象，用在底图对象上绘图
    Graphics2D g2d = buffImg.createGraphics();
    int waterImgWidth = waterImg.getWidth();// 获取层图的宽度
    int waterImgHeight = waterImg.getHeight();// 获取层图的高度
    // 在图形和图像中实现混合和透明效果
    g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));
    // 绘制
    g2d.drawImage(waterImg, x, y, waterImgWidth, waterImgHeight, null);
    g2d.dispose();// 释放图形上下文使用的系统资源
    return buffImg;
  }

  /**
   * 输出水印图片
   * 
   * @param buffImg
   *      图像加水印之后的BufferedImage对象
   * @param savePath
   *      图像加水印之后的保存路径
   */
  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异常直接抛出了
   * @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();
    // 构建叠加层
    BufferedImage buffImg = NewImageUtils.watermark(new File(sourceFilePath), new File(waterFilePath), 0, 0, 1.0f);
    // 输出水印图片
    newImageUtils.generateWaterFile(buffImg, saveFilePath);
  }
}