java根据指定大小kb压缩图片

/*** 根据指定大小压缩图片** @param sourceFilePath 源图片路径 + 文件名* @param outFilePath 生成之后的图片路径 + 文件名* @param desFileSize 指定图片大小，单位kb* @return 压缩质量后的图片字节数组*/public static byte[] compressPicForScale(String sourceFilePath, String outFilePath, long desFileSize) {if (StringUtils.isEmpty(sourceFilePath)) {return null;}byte[] imageBytes = null;try {imageBytes = FileUtils.readFileToByteArray(new File(sourceFilePath));if (imageBytes == null || imageBytes.length <= 0 || imageBytes.length < desFileSize * 1024) {FileUtils.writeByteArrayToFile(new File(outFilePath), imageBytes);log.info("pressPicForScale 图片无需压缩，原始大小为：{}kb, sourceFilePath:{}", imageBytes.length / 1024, sourceFilePath);return imageBytes;}long srcSize = imageBytes.length;long size = srcSize / 1024;// 自动调节精度(经验数值)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;}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();}if (outFilePath != null) {log.info("pressPicForScale 图片压缩后大小：{}kb, sourceFilePath:{}", imageBytes.length / 1024, sourceFilePath);FileUtils.writeByteArrayToFile(new File(outFilePath), imageBytes);}} catch (Exception e) {log.error("图片压缩发生异常。sourceFilePath:{}, errorMessage:{}", sourceFilePath, e.getMessage(), e);}return imageBytes;}