package test;

 import java.awt.Dimension;

 import java.awt.image.BufferedImage;

 import java.io.File;

 import java.io.IOException;

 import java.util.Iterator;

 import javax.imageio.ImageIO;

 import javax.imageio.ImageReader;

 import javax.imageio.stream.FileImageInputStream;

 import javax.imageio.stream.ImageInputStream;

 /**

  * 读取大图片的分辨率

  *

  * @author 远方bruce

  *

  */

 public class ReadResolution {

     /**

      * 通过BufferedImage获取

      * @param file 文件

      * @return 图片的分辨率

      * @throws IOException

      */

     public static String getResolution1(File file) throws IOException {

         BufferedImage image = ImageIO.read(file);

         return image.getWidth() + "x" + image.getHeight();

     }

     /**

      * 获取图片的分辨率

      *

      * @param path

      * @return

      */

     public static Dimension getImageDim(String path) {

         Dimension result = null;

         String suffix = getFileSuffix(path);

         //解码具有给定后缀的文件

         Iterator<ImageReader> iter = ImageIO.getImageReadersBySuffix(suffix);

         System.out.println(ImageIO.getImageReadersBySuffix(suffix));

         if (iter.hasNext()) {

             ImageReader reader = iter.next();

             try {

                 ImageInputStream stream = new FileImageInputStream(new File(

                         path));

                 reader.setInput(stream);

                 int width = reader.getWidth(reader.getMinIndex());

                 int height = reader.getHeight(reader.getMinIndex());

                 result = new Dimension(width, height);

             } catch (IOException e) {

                 e.printStackTrace();

             } finally {

                 reader.dispose();

             }

         }

         System.out.println("getImageDim:" + result);

         return result;

     }

     /**

      * 获得图片的后缀名

      * @param path

      * @return

      */

     private static String getFileSuffix(final String path) {

         String result = null;

         if (path != null) {

             result = "";

             if (path.lastIndexOf('.') != -1) {

                 result = path.substring(path.lastIndexOf('.'));

                 if (result.startsWith(".")) {

                     result = result.substring(1);

                 }

             }

         }

         System.out.println("getFileSuffix:" + result);

         return result;

     }

     /**

      * 截取Dimension对象获得分辨率

      * @param path

      *

      * @return

      */

     public static String getResolution2(String path) {

         String s = getImageDim(path).toString();

         s = s.substring(s.indexOf("[") + 1, s.indexOf("]"));

         String w = s.substring(s.indexOf("=") + 1, s.indexOf(","));

         String h = s.substring(s.lastIndexOf("=") + 1);

         String result = w + " x " + h;

         System.out.println("getResolution:" + result);

         return result;

     }

     /**

      * 测试

      *

      * @param args

      * @throws IOException

      */

     public static void main(String[] args) throws IOException {

         String path = "d:\\abc.JPG";

         File file = new File(path);

         System.out.println("第1种方法使用的时间：");

         long s1 = System.currentTimeMillis();

         System.out.println(getResolution1(file));

         long l1 = System.currentTimeMillis();

         System.out.println((l1 - s1)+"ms");

         System.out.println("******************************");

         System.out.println("第2种方法使用的时间：");

         long s2 = System.currentTimeMillis();

         getResolution2(path);

         long l2 = System.currentTimeMillis();

         System.out.println((l2 - s2)+"ms");

     }

 }