第二种是添加图片水印和文字水印两种方法，水印图片可以是GIF,PNG透明的文件，我一般采用的是PNG的，因为它的质量和GIF相比要高一些：

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import javax.imageio.ImageIO;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public final class ImageUtils {
public ImageUtils() {
}
/**//*
* public final static String getPressImgPath() { return ApplicationContext
* .getRealPath("/template/data/util/shuiyin.gif"); }
*/
/** *//**
* 把图片印刷到图片上
*
* @param pressImg --
*            水印文件
* @param targetImg --
*            目标文件
* @param x
*            --x坐标
* @param y
*            --y坐标
*/
public final static void pressImage(String pressImg, String targetImg,
int x, int y) {
try {
//目标文件
            File _file = new File(targetImg);
Image src = ImageIO.read(_file);
int wideth = src.getWidth(null);
int height = src.getHeight(null);
BufferedImage image = new BufferedImage(wideth, height,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.createGraphics();
g.drawImage(src, 0, 0, wideth, height, null);
//水印文件
            File _filebiao = new File(pressImg);
Image src_biao = ImageIO.read(_filebiao);
int wideth_biao = src_biao.getWidth(null);
int height_biao = src_biao.getHeight(null);
g.drawImage(src_biao, (wideth - wideth_biao) / 2,
(height - height_biao) / 2, wideth_biao, height_biao, null);
//水印文件结束
            g.dispose();
FileOutputStream out = new FileOutputStream(targetImg);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/** *//**
* 打印文字水印图片
*
* @param pressText
*            --文字
* @param targetImg --
*            目标图片
* @param fontName --
*            字体名
* @param fontStyle --
*            字体样式
* @param color --
*            字体颜色
* @param fontSize --
*            字体大小
* @param x --
*            偏移量
* @param y
*/
public static void pressText(String pressText, String targetImg,
String fontName, int fontStyle, int color, int fontSize, int x,
int y) {
try {
File _file = new File(targetImg);
Image src = ImageIO.read(_file);
int wideth = src.getWidth(null);
int height = src.getHeight(null);
BufferedImage image = new BufferedImage(wideth, height,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.createGraphics();
g.drawImage(src, 0, 0, wideth, height, null);
// String s="www.qhd.com.cn";
            g.setColor(Color.RED);
g.setFont(new Font(fontName, fontStyle, fontSize));
g.drawString(pressText, wideth - fontSize - x, height - fontSize
/ 2 - y);
g.dispose();
FileOutputStream out = new FileOutputStream(targetImg);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
out.close();
} catch (Exception e) {
System.out.println(e);
}
}
public static void main(String[] args) {
pressImage("F:/logo.png",          "F:/123.jpg", 0, 0);
}
}