JAVA实现图片叠加效果

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);
}
}