1:先导入依赖
<!--thumbnailator图片处理--><dependency><groupId>net.coobird</groupId><artifactId>thumbnailator</artifactId><version>0.4.8</version></dependency>
2:创建工具类--->PicUtils
import net.coobird.thumbnailator.Thumbnails;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;/*** @PROJECT_NAME: fdfs* @AUTHOR: zhang* @DATE: -01-13 10:01* @DESCRIPTION: 图片压缩工具* @VERSION:*/public class PicUtils {//以下是常量,按照阿里代码开发规范,不允许代码中出现魔法值private static final Logger logger = LoggerFactory.getLogger(PicUtils.class);private static final Integer ZERO = 0;private static final Integer ONE_ZERO_TWO_FOUR = 1024;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;/*** 根据指定大小压缩图片** @param imageBytes 源图片字节数组* @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(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】msg=图片压缩失败!", e);}return imageBytes;}/*** 自动调节精度(经验数值)** @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 < 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;}}
3:在上传图片接口处进行压缩
/*** 图片上传*/@PostMapping("file/img")@ApiOperation(value = "图片上传接口")public Result imgUploads(@RequestParam("file") MultipartFile file) throws IOException {//压缩图片到指定120K以内,不管你的图片有多少兆,都不会超过120kb,精度还算可以,不会模糊byte[] bytes = pressPicForScale(file.getBytes(), 120);ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);//生成保存在服务器的图片名称，统一修改原后缀名为:jpgString newFileName = UUID.randomUUID() + ".jpg";OSSUtil.upload2(newFileName, inputStream);JSONObject result = new JSONObject();result.put("url", OSSUtil.getUrl2(newFileName, ""));return Result.success(result);}
还有一个压缩图片工具类,但是不能指定压缩大小,可是很有用,压缩不会丢失精度,图片也很清晰:
import com.mon.enums.ResultEnum;import com.mon.exception.GlobalException;import org.springframework.web.multipart.MultipartFile;import javax.imageio.ImageIO;import java.awt.*;import java.awt.image.BufferedImage;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;/*** @PROJECT_NAME: fdfs* @AUTHOR: zhang* @DATE: -01-13 10:33* @DESCRIPTION: 图片压缩工具* @VERSION:*/public class ImgCompression {public static InputStream getImageCom(MultipartFile file) throws IOException {//获取文件输入流InputStream inputStream = file.getInputStream();try {// 把图片读入到内存中BufferedImage bufImg = ImageIO.read(inputStream);// 压缩代码,存储图片文件byte数组ByteArrayOutputStream bos = new ByteArrayOutputStream();//防止图片变红,这一步非常重要BufferedImage bufferedImage = new BufferedImage(bufImg.getWidth(), bufImg.getHeight(), BufferedImage.TYPE_INT_RGB);bufferedImage.createGraphics().drawImage(bufImg,0,0, Color.WHITE,null);//先转成jpg格式来压缩,然后在通过OSS来修改成源文件本来的后缀格式ImageIO.write(bufferedImage,"jpg",bos);//获取输出流inputStream = new ByteArrayInputStream(bos.toByteArray());return inputStream;} catch (IOException e) {e.printStackTrace();throw new GlobalException(ResultEnum.IMG_UPLOAD_ERROR);}finally {inputStream.close();}}}
