image工具类谷歌图片压缩

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.sql.Blob;

import org.apache.commons.codec.binary.Base64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import net.coobird.thumbnailator.Thumbnails;

public class ImageUtils {

private static final Logger logger = LoggerFactory.getLogger(ImageUtils.class);

/**
 * 将图片转换为byte
 * @date 2018年9月11日 下午4:17:47
 */
public static byte[] blobToByte(Blob blob){
	if(blob == null){
		logger.info("blob 为空");
	}
	
	byte[] data = null;
	try {
		InputStream inStream = blob.getBinaryStream();
		long nLen = blob.length();
		int nSize = (int) nLen;
		data = new byte[nSize];
		inStream.read(data);
		inStream.close();
	} catch (Exception e) {
		logger.info("获取图片数据失败,原因:" + e.getMessage());
	}
	
	return data;
}

/**
 * 对字节数组Base64编码
 * @date 2018年9月11日 下午4:20:29
 */
 public static String imageToBase64(byte[] data){
	 String base64 = new String(Base64.encodeBase64(data));
	 return base64;
 }

 
 /**
 * 根据指定大小压缩图片
 * @author cuishiliang
 * @param imageBytes  源图片字节数组
 * @param desFileSize 指定图片大小，单位kb
 * @param imageId     影像编号
 * @return 压缩质量后的图片字节数组
 */
public static byte[] compressPicForScale(byte[] imageBytes, long desFileSize, String imageId) {
    if (imageBytes == null || imageBytes.length <= 0 || imageBytes.length < desFileSize * 1024) {
        return imageBytes;
    }
    long srcSize = imageBytes.length;
    double accuracy = getAccuracy(srcSize / 1024);
    try {
        while (imageBytes.length > desFileSize * 1024) {
            ByteArrayInputStream inputStream = new ByteArrayInputStream(imageBytes);
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream(imageBytes.length);
            Thumbnails.of(inputStream)
                    .scale(accuracy)
                    .outputQuality(accuracy)
                    .toOutputStream(outputStream);
            imageBytes = outputStream.toByteArray();
        }
        logger.info("【图片压缩】imageId={} | 图片原大小={}kb | 压缩后大小={}kb",
                imageId, srcSize / 1024, imageBytes.length / 1024);
    } catch (Exception e) {
        logger.error("【图片压缩】msg=图片压缩失败!", e);
    }
    return imageBytes;
}
 
/**
 * 自动调节精度(经验数值)
 * @author cuishiliang
 * @param size 源图片大小
 * @return 图片压缩质量比
 */
private static double getAccuracy(long size) {
    double accuracy;
    if (size < 900) {
        accuracy = 0.85;
    } else if (size < 2047) {
        accuracy = 0.6;
    } else if (size < 3275) {
        accuracy = 0.44;
    } else {
        accuracy = 0.4;
    }
    return accuracy;
}

}