java实现压缩图片且不改变原图尺寸

需求：

大于2MB的图片需要压缩到2MB以下，且不改变原图的尺寸。

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引入依赖：

        <dependency>             <groupId>net.coobird</groupId>             <artifactId>thumbnailator</artifactId>             <version>0.4.8</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; }

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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();             }             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;     } }