压缩图片工具类，压缩100KB以内拿走直接用

最近遇到自拍上传图片过大问题，很烦恼，所以自己写了一个压缩图片的工具类使用，自测效果很不错，可以压缩到KB以内，像素还可以分辨清晰

下面Java代码奉上：

 import lombok.extern.slf4j.Slf4j;
 import org.w3c.dom.Element;

 import javax.imageio.IIOImage;
 import javax.imageio.ImageIO;
 import javax.imageio.ImageTypeSpecifier;
 import javax.imageio.ImageWriter;
 import javax.imageio.metadata.IIOMetadata;
 import javax.imageio.plugins.jpeg.JPEGImageWriteParam;
 import javax.imageio.stream.ImageOutputStream;
 import java.awt.*;
 import java.awt.image.BufferedImage;
 import java.io.*;
 import java.net.HttpURLConnection;
 import java.net.URL;

 /**
  * @Author: Mr. Chang
  */
 @Slf4j
 public class ImageZipUtils {

     /**
      * 采用指定宽度、高度或压缩比例 的方式对图片进行压缩
      *
      * @param imgsrc     源图片地址
      * @param imgdist    目标图片地址
      * @param widthdist  压缩后图片宽度（当rate==null时，必传）
      * @param heightdist 压缩后图片高度（当rate==null时，必传）
      * @param rate       压缩比例
      */
     public static void reduceImg(String imgsrc, String imgdist, int widthdist,
                                  int heightdist, Float rate) {
         try {
             File srcfile = new File(imgsrc);
             // 检查文件是否存在
             if (!srcfile.exists()) {
                 return;
             }
             // 如果rate不为空说明是按比例压缩
             if (rate != null && rate > 0) {
                 // 获取文件高度和宽度
                 int[] results = getImgWidth(srcfile);
                 if (results == null || results[0] == 0 || results[1] == 0) {
                     return;
                 } else {
                     widthdist = (int) (results[0] * rate);
                     heightdist = (int) (results[1] * rate);
                 }
             }
             // 开始读取文件并进行压缩
             Image src = javax.imageio.ImageIO.read(srcfile);
             BufferedImage tag = new BufferedImage((int) widthdist,
                     (int) heightdist, BufferedImage.TYPE_INT_RGB);

             tag.getGraphics().drawImage(
                     src.getScaledInstance(widthdist, heightdist,
                             Image.SCALE_SMOOTH), 0, 0, null);

             FileOutputStream out = new FileOutputStream(imgdist);
 //            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
 //            encoder.encode(tag);
 //            out.close();
             float per = (float) 0.85;
             saveAsJPEG(100, tag, per, out);

         } catch (IOException ex) {
             ex.printStackTrace();
         }
     }

     /**
      * 以JPEG编码保存图片
      *
      * @param dpi             分辨率
      * @param image_to_save   要处理的图像图片
      * @param JPEGcompression 压缩比
      * @param fos             文件输出流
      * @throws IOException
      */
     public static void saveAsJPEG(Integer dpi, BufferedImage image_to_save, float JPEGcompression, FileOutputStream fos) throws IOException {
         // Image writer
         ImageWriter imageWriter = ImageIO.getImageWritersBySuffix("jpg").next();
         ImageOutputStream ios = ImageIO.createImageOutputStream(fos);
         imageWriter.setOutput(ios);
         //and metadata
         IIOMetadata imageMetaData = imageWriter.getDefaultImageMetadata(new ImageTypeSpecifier(image_to_save), null);

         if (dpi != null && !dpi.equals("")) {

             //new metadata
             Element tree = (Element) imageMetaData.getAsTree("javax_imageio_jpeg_image_1.0");
             Element jfif = (Element) tree.getElementsByTagName("app0JFIF").item(0);
             jfif.setAttribute("Xdensity", Integer.toString(dpi));
             jfif.setAttribute("Ydensity", Integer.toString(dpi));

         }

         if (JPEGcompression >= 0 && JPEGcompression <= 1f) {
             // new Compression
             JPEGImageWriteParam jpegParams = (JPEGImageWriteParam) imageWriter.getDefaultWriteParam();
             jpegParams.setCompressionMode(JPEGImageWriteParam.MODE_EXPLICIT);
             jpegParams.setCompressionQuality(JPEGcompression);

         }

         //new Write and clean up
         imageWriter.write(imageMetaData, new IIOImage(image_to_save, null, null), null);
         ios.close();
         imageWriter.dispose();

     }

     /**
      * 获取图片宽度
      *
      * @param file 图片文件
      * @return 宽度
      */
     public static int[] getImgWidth(File file) {
         InputStream is = null;
         BufferedImage src = null;
         int result[] = {0, 0};
         try {
             is = new FileInputStream(file);
             src = javax.imageio.ImageIO.read(is);
             result[0] = src.getWidth(null); // 得到源图宽
             result[1] = src.getHeight(null); // 得到源图高
             is.close();
         } catch (Exception e) {
             e.printStackTrace();
         }
         return result;
     }

     public static byte[] readInputStream(InputStream inStream) throws Exception {
         ByteArrayOutputStream outStream = new ByteArrayOutputStream();
         //创建一个Buffer字符串
         byte[] buffer = new byte[1024];
         //每次读取的字符串长度，如果为-1，代表全部读取完毕
         int len = 0;
         //使用一个输入流从buffer里把数据读取出来
         while ((len = inStream.read(buffer)) != -1) {
             //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
             outStream.write(buffer, 0, len);
         }
         //关闭输入流
         inStream.close();
         //把outStream里的数据写入内存
         return outStream.toByteArray();
     }

     /**
      * 保存自拍照片
      * @param userId
      * @param photo_url
      * @param suffixFromUrl
      * @param path
      * @throws Exception
      */
     public static void saveZipImage(Integer userId, String photo_url, String suffixFromUrl, String path) throws Exception {

         //new一个URL对象
         URL url = new URL(photo_url);
         //打开链接
         HttpURLConnection conn = (HttpURLConnection) url.openConnection();
         //设置请求方式为"GET"
         conn.setRequestMethod("GET");
         //超时响应时间为5秒
         conn.setConnectTimeout(5 * 1000);
         //通过输入流获取图片数据
         InputStream inStream = conn.getInputStream();
         //得到图片的二进制数据，以二进制封装得到数据，具有通用性
         byte[] data = readInputStream(inStream);
         //new一个文件对象用来保存图片，默认保存当前工程根目录
         File imageFile = new File(path + userId + suffixFromUrl);
         //创建输出流
         FileOutputStream outStream = new FileOutputStream(imageFile);
         //写入数据
         outStream.write(data);
         //关闭输出流
         outStream.close();

     }

     /**
      * 开始压缩图片
      * @param userId
      * @param suffix
      * @param path
      * @return
      */
     public static String imageZipStart(Integer userId, String suffix, String path) {
         /**
          * d://3.jpg 源图片
          * d://31.jpg 目标图片
          * 压缩宽度和高度都是1000
          *
          */
         String original = path + userId + suffix;
         String target = path + userId + "target" + suffix;
         File srcfile = new File(original);
         log.info(userId + "用户自拍照压缩前自拍照大小:" + srcfile.length());
         reduceImg(original, target, 888, 888, null);
         File distfile = new File(target);
         log.info("用户自拍照压缩后自拍照大小:" + distfile.length());
         return target;
     }

     /**
      * 删除文件
      */
     public static void delFile(String fileName) {
         File deFile = new File(fileName);
         if (deFile.exists()) {
             deFile.delete();
         }
     }

 }

如有更正，欢迎下方评论联系我，谢谢