Java 图片压缩

1.引入包

        <!--thumbnailator图片处理 压缩 裁剪 工具-->
        <dependency>
            <groupId>net.coobird</groupId>
            <artifactId>thumbnailator</artifactId>
            <version>0.4.8</version>
        </dependency>

2.工具类

/**
 * @description: 图片上传工具类
 */
@Component
public class UploadCodeUtils {

    /**
     * @Description: 压缩比值，可以随意调节
     * @Return: null
     **/
    private static final Logger logger = LoggerFactory.getLogger(UploadCodeUtils.class);
    private static final Integer ZERO = 0;
    private static final Integer ONE_ZERO_TWO_FOUR = 1024;
    private static final Integer TWO_ZERO_FOUR_EIGHT = 2048;
    private static final Integer NINE_ZERO_ZERO = 900;
    private static final Integer THREE_TWO_SEVEN_FIVE = 3275;
    private static final Integer TWO_ZERO_FOUR_SEVEN = 2047;
    private static final Double ZERO_EIGHT_FIVE = 0.85;
    private static final Double ZERO_SIX = 0.6;
    private static final Double ZERO_FOUR_FOUR = 0.44;
    private static final Double ZERO_FOUR = 0.4;


    /**
     * @Description: 根据指定大小压缩图片
     * @Param [imageBytes：源图片字节数组, desFileSize：指定图片大小，单位kb]
     * @Return: byte[] 压缩后的图片字节数组
     **/
    public static byte[] compressPicForScale(byte[] imageBytes, long desFileSize) {
        if (imageBytes == null || imageBytes.length <= ZERO || imageBytes.length < desFileSize * ONE_ZERO_TWO_FOUR) {
            return imageBytes;
        }
        long srcSize = imageBytes.length;
        double accuracy = getAccuracy(srcSize / ONE_ZERO_TWO_FOUR);
        try {
            while (imageBytes.length > desFileSize * ONE_ZERO_TWO_FOUR) {
                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("图片原大小={}kb | 压缩后大小={}kb",
                    srcSize / ONE_ZERO_TWO_FOUR, imageBytes.length / ONE_ZERO_TWO_FOUR);
        } catch (Exception e) {
            logger.error("图片压缩失败!", e);
        }
        return imageBytes;
    }

    /**
     * @Description: 自动调节精度(经验数值)，按照图划分4级
     * @Param [size：源图片大小]
     * @Return: double 图片压缩质量比
     **/
    private static double getAccuracy(long size) {
        double accuracy;
        //判断图片大小 进行等比例压缩
        if (size < NINE_ZERO_ZERO) {
            accuracy = ZERO_EIGHT_FIVE;
        } else if (size < TWO_ZERO_FOUR_SEVEN) {
            accuracy = ZERO_SIX;
        } else if (size < THREE_TWO_SEVEN_FIVE) {
            accuracy = ZERO_FOUR_FOUR;
        } else {
            accuracy = ZERO_FOUR;
        }
        return accuracy;
    }

    /**
     * @Description: byte数组 转 InputStream
     * @Param [bytes]
     * @Return: java.io.InputStream
     **/
    public static InputStream byteToInputStream(byte[] bytes) {
        return new ByteArrayInputStream(bytes);
    }


    /**
     * @Description: InputStream 转 byte数组
     * @Param [inputStream]
     * @Return: byte[]
     **/
    public static byte[] inputStreamToByte(InputStream inputStream) throws IOException {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        byte[] buff = new byte[100];
        int rc = 0;
        while ((rc = inputStream.read(buff, 0, 100)) > 0) {
            byteArrayOutputStream.write(buff, 0, rc);
        }
        return byteArrayOutputStream.toByteArray();
    }
}