个回答

• 寒深

  2019-01-16 13:50:17

  @Service
  public class ThumbnailService {
      public static final int WIDTH  = 100;
      public static final int HEIGHT = 100;
  
      //使用类库
      public String thumbnail(MultipartFile file,String uploadPath, String realUploadPath){
          String imgName = "thum_"+file.getOriginalFilename();
          String des = realUploadPath+"/"+imgName;
          try {
              Thumbnails.of(file.getInputStream()).size(WIDTH,HEIGHT).toFile(des);
          }catch (Exception e){
              e.printStackTrace();
          }
          return uploadPath+"/"+imgName;
      }
  
      //使用java awt
      public String awt(MultipartFile file,String uploadPath, String realUploadPath){
          OutputStream os = null;
          String imgName = "thum_"+file.getOriginalFilename();
          String des = realUploadPath+"/"+imgName;
          try {
              os = new FileOutputStream(des);
              Image image = ImageIO.read(file.getInputStream());
              int width = image.getWidth(null);//原图宽
              int height = image.getHeight(null);//原图高
              int rate1 = width/WIDTH;//缩略图宽比例
              int rate2 = height/HEIGHT;//缩略图高比例
              int rate = 0;
              if(rate1 > rate2){//宽度缩略比例大于高度缩略比例，使用宽度缩略比例
                  rate = rate1;
              }else {
                  rate = rate2;
              }
              //计算缩略图最终的宽度和高度
              int newWidth = width/rate;
              int newHeight = height/rate;
              BufferedImage bufferedImage = new BufferedImage(newWidth,newHeight,BufferedImage.TYPE_INT_RGB);
              bufferedImage.getGraphics().drawImage(image.getScaledInstance(newWidth,newHeight,image.SCALE_SMOOTH),0,0,null);
              String imageType = file.getContentType().substring(file.getContentType().indexOf("/")+1);
              ImageIO.write(bufferedImage,imageType,os);
          }catch (Exception e){
              e.printStackTrace();
          }finally {
              if(os!=null){
                  try {
                      os.close();
                  }catch (Exception e){
                      e.printStackTrace();
                  }
              }
          }
          return uploadPath+"/"+imgName;
      }
  }

  
  

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