Thumbnailator图片缩放

指定大小进行缩放

public class PicUtil {  
    public static void main(String[] args) {    
            
        PicUtil.commpressPicForSize("G:\\images\\ceshi.jpg",    
                "G:\\images\\datas\\ceshi.jpg", 100, 0.3); // 图片小于100kb  
          
    }    
    
    /**  
     * 根据指定大小和指定精度压缩图片  
     *   
     * @param srcPath  
     *            源图片地址  
     * @param desPath  
     *            目标图片地址  
     * @param desFilesize  
     *            指定图片大小，单位kb  
     * @param accuracy  
     *            精度，递归压缩的比率，建议小于0.9  
     * @return  
     */    
    public static String commpressPicForSize(String srcPath, String desPath,    
            long desFileSize, double accuracy) {    
        if (StringUtils.isEmpty(srcPath) || StringUtils.isEmpty(srcPath)) {    
            return null;    
        }    
        if (!new File(srcPath).exists()) {    
            return null;    
        }    
        try {    
            File srcFile = new File(srcPath);    
            long srcFileSize = srcFile.length();    
            System.out.println("源图片：" + srcPath + "，大小：" + srcFileSize / 1024    
                    + "kb");    
    
            // 1、先转换成jpg    
            Thumbnails.of(srcPath).scale(1f).toFile(desPath);    
            // 递归压缩，直到目标文件大小小于desFileSize    
            commpressPicCycle(desPath, desFileSize, accuracy);  
    
            File desFile = new File(desPath);    
            System.out.println("目标图片：" + desPath + "，大小" + desFile.length()    
                    / 1024 + "kb");    
            System.out.println("图片压缩完成！");    
        } catch (Exception e) {    
            e.printStackTrace();    
            return null;    
        }    
        return desPath;    
    }  
    /** 
     * 图片压缩:按指定大小把图片进行缩放（会遵循原图高宽比例） 
     * 并设置图片文件大小 
     */  
    private static void commpressPicCycle(String desPath, long desFileSize,    
            double accuracy) throws IOException {    
        File srcFileJPG = new File(desPath);    
        long srcFileSizeJPG = srcFileJPG.length();    
        // 2、判断大小，如果小于指定大小，不压缩；如果大于等于指定大小，压缩    
        if (srcFileSizeJPG <= desFileSize * 1024) {  
            return;    
        }    
        // 计算宽高    
        BufferedImage bim = ImageIO.read(srcFileJPG);    
        int srcWdith = bim.getWidth();    
        int srcHeigth = bim.getHeight();    
        int desWidth = new BigDecimal(srcWdith).multiply(    
                new BigDecimal(accuracy)).intValue();    
        int desHeight = new BigDecimal(srcHeigth).multiply(    
                new BigDecimal(accuracy)).intValue();    
    
        Thumbnails.of(desPath).size(desWidth, desHeight)    
                .outputQuality(accuracy).toFile(desPath);    
        commpressPicCycle(desPath, desFileSize, accuracy);    
    }  
}

按照比例进行缩放

public class PicUtil {  
    public static void main(String[] args) {  
            PicUtil.commpressPicForScale("G:\\images\\ceshi.jpg",   
                "G:\\images\\scales\\ceshi.jpg", 100,0.3);  
        }  
        public static String commpressPicForScale(String srcPath, String desPath,    
            long desFileSize, double accuracy) {    
           if (StringUtils.isEmpty(srcPath) || StringUtils.isEmpty(srcPath)) {    
               return null;    
             }    
           if (!new File(srcPath).exists()) {    
               return null;    
           }    
           try {    
              File srcFile = new File(srcPath);    
              long srcFileSize = srcFile.length();    
              System.out.println("源图片：" + srcPath + "，大小：" + srcFileSize / 1024    
                    + "kb");    
    
              // 1、先转换成jpg    
              Thumbnails.of(srcPath).scale(1f).toFile(desPath);    
              //按照比例进行缩放  
              imgScale(desPath, desFileSize, accuracy);  
    
              File desFile = new File(desPath);    
              System.out.println("目标图片：" + desPath + "，大小" + desFile.length()    
                    / 1024 + "kb");    
              System.out.println("图片压缩完成！");    
          } catch (Exception e) {    
              e.printStackTrace();    
              return null;    
          }    
          return desPath;    
     }  
   <span style="white-space:pre;">  </span>/** 
     <span style="white-space:pre;">    </span>* 按照比例进行缩放  
     <span style="white-space:pre;">    </span>*  
     <span style="white-space:pre;">    </span>*/  
      private static void imgScale(String desPath, long desFileSize,    
            double accuracy) throws IOException{  
          File file=new File(desPath);  
          long fileSize=file.length();  
          //判断大小，如果小于指定大小，不压缩；如果大于等于指定大小，压缩  
          if(fileSize<=desFileSize*1024){  
            return;  
          }  
          //按照比例进行缩小  
          Thumbnails.of(desPath).scale(accuracy).toFile(desPath);//按比例缩小  
          System.out.println("按照比例进行缩放");  
          imgScale(desPath, desFileSize, accuracy);  
    }  
}