Thumbnailator实现图片压缩，旋转，添加水印

先看一下效果图吧：

主要的代码如下：

package sea;

import net.coobird.thumbnailator.Thumbnails;
import net.coobird.thumbnailator.geometry.Positions;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * User: Greta.Wang
 * Date: 12-11-3
 * Read nine pictures from file system, and compose them to one, in the process, each picture will be added a watermark.
 */
public class ComposePicture {
    public static void main(String args[])
            throws IOException {
        //从工程中去读九张图片，并对图片做进一步的处理（缩小比例，旋转30度，加水印），并把图片保存在内存中做进一步的处理
        List<BufferedImage> bufferedImageList = readPicturesToMemory();
        //在内存中，合并九张图片成一张图片
        BufferedImage bufferedImageNineByNine = composeNinePicturesToOne(bufferedImageList);
        //把内存中的图片写入到指定的文件中
        File fileOutPut = new File(System.getProperty("user.dir") + "/handledpictures/compose.jpg");
        ImageIO.write(bufferedImageNineByNine, "jpg", fileOutPut);
    }
    public static List<BufferedImage> readPicturesToMemory()
            throws IOException {
        String[] pathArray = new String[9];
        List<BufferedImage> bufferedImageList = new ArrayList<BufferedImage>();
        //Thumbnail读取水印文件到内存中
        BufferedImage waterMarkBufferedImage = Thumbnails.of(ComposePicture.class.getClassLoader().getResource("5.png").getFile())
                //Thumbnail的方法，根据比例缩小，0.4f意思是缩小到原图的40%
                .scale(0.4f)
                //读取成BufferedImage对象
                .asBufferedImage();
        //读取9张待处理的图片到内存中
        for (int i = 0; i < 9; i++) {
            //取得图片的路径
            pathArray[i] = ComposePicture.class.getClassLoader().getResource("IMG_000" + i + ".JPG").getFile();
            BufferedImage image = Thumbnails.of(pathArray[i])
                    //按比例缩小
                    .scale(0.05f)
                    //加水印，0.5f表示的是透明度
                    .watermark(Positions.CENTER, waterMarkBufferedImage, 0.5f)
                    //旋转30度
                    .rotate(30)
                    //读取成BufferedImage对象
                    .asBufferedImage();
            bufferedImageList.add(image);
        }
        return bufferedImageList;
    }

    public static BufferedImage composeNinePicturesToOne(List<BufferedImage> bufferedImageList) {
        //取得处理后图像的宽度和高度，要处理的9张图片有相同的高度和宽度
        int width = bufferedImageList.get(0).getWidth();
        int height = bufferedImageList.get(0).getHeight();
        List<int[]> imageArrayList = new ArrayList<int[]>();
        for (BufferedImage bufferedImage : bufferedImageList) {
            int[] oneImageArray = new int[width * height];
            //读取图片成byte数组
            oneImageArray = bufferedImage.getRGB(0, 0, width, height, oneImageArray, 0, width);
            imageArrayList.add(oneImageArray);
        }
        //合并图片到同一个bufferedImage对象中
        BufferedImage bufferedImageNineByNine = new BufferedImage(width * 3, height * 3, BufferedImage.TYPE_INT_RGB);
        int x = 0;
        int y = 0;
        //根据x，y的坐标，先输出x轴上的三张，然后输出y轴上的图片
        for (int[] buffered : imageArrayList) {
            bufferedImageNineByNine.setRGB(width * y, height * x, width, height, buffered, 0, width);
            y++;
            if (y % 3 == 0) {
                y = 0;
                x++;
            }
        }
        return bufferedImageNineByNine;
    }
}