Java实现图片压缩且不改变原图尺寸

最近工作中涉及图片压缩相关的操作,需求如下:

大于2MB的图片需要压缩到2MB以下,且不改变原图的尺寸

引入依赖

        dependency
            groupIdnet.coobird/groupId
            artifactIdthumbnailator/artifactId
            version0.4.8/version
        /dependency

附件实体类

@Builder
@NoArgsConstructor
@AllArgsConstructor
@Data
public class FileCO {
    /**
     * 附件字节流
     */
    private byte[] fileContent;

    /**
     * 附件OID
     */
    private UUID attachmentOid;
}

图片实体类

@Builder
@NoArgsConstructor
@AllArgsConstructor
@Data
public class ImageInfo {

    /**
     * 图片字节流
     */
    private byte[] imageBytes;

    /**
     * 图片是否进行压缩
     */
    private Boolean compressFlag;

    /**
     * 图片宽度
     */
    private Integer width;

    /**
     * 图片高度
     */
    private Integer height;
}

图片压缩工具类

@Slf4j
public class ImageUtils {

    /**
     * 合法图片大小为2MB
     */
    private static final Long LEGAL_IMAGE_SIZE = 1024 * 2L;

    /**
     * 图片压缩 当图片大小大于2MB进行等比例压缩
     * 不修改图片尺寸进行压缩
     *
     * @param fileCO
     * @return
     */
    public static ImageInfo compressImageForScale(FileCO fileCO) throws IOException {
        byte[] imageBytes = fileCO.getFileContent();
        UUID attachmentOid = fileCO.getAttachmentOid();
        try {
            BufferedImage sourceImage = ImageIO.read(new ByteArrayInputStream(imageBytes));
            //高度
            int height = sourceImage.getHeight();
            //宽度
            int width = sourceImage.getWidth();
            if (imageBytes.length = 0 || imageBytes.length  LEGAL_IMAGE_SIZE * 1024) {
                return ImageInfo.builder()
                        .imageBytes(imageBytes)
                        .width(width)
                        .height(height)
                        .compressFlag(false)
                        .build();
            }
            long srcSize = imageBytes.length;
            double accuracy = getAccuracy(srcSize / 1024);

            while (imageBytes.length  LEGAL_IMAGE_SIZE * 1024) {
                ByteArrayInputStream inputStream = new ByteArrayInputStream(imageBytes);
                ByteArrayOutputStream outputStream = new ByteArrayOutputStream(imageBytes.length);
                Thumbnails.of(inputStream)
                        .scale(1f)
                        .outputQuality(accuracy)
                        .toOutputStream(outputStream);
                imageBytes = outputStream.toByteArray();
                //如果压缩后图片大小未改变则跳出循环,防止死循环
                if (srcSize == imageBytes.length) {
                    log.warn("[图片压缩]msg=图片压缩失败,图片大小未改变!");
                    break;
                }
            }
            log.info("[图片压缩]附件OID={} | 图片原大小={}kb | 压缩后大小={}kb",
                    attachmentOid, srcSize / 1024, imageBytes.length / 1024);
            return ImageInfo.builder()
                    .imageBytes(imageBytes)
                    .width(width)
                    .height(height)
                    .compressFlag(true)
                    .build();
        } catch (Exception e) {
            log.error("[图片压缩]msg=图片压缩失败!", e);
            throw e;
        }
    }

    /**
     * 计算压缩精度
     *
     * @param size
     * @return
     */
    private static double getAccuracy(long size) {
        double accuracy;
        //图片大小小于4M,压缩精度为0.44;否则精度为0.4
        if (size = 2048 * 2) {
            accuracy = 0.44;
        } else {
            accuracy = 0.4;
        }
        return accuracy;
    }
}
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