android ---- ImageUtil工具类

package com.itcast.util;        import java.io.BufferedInputStream;    import java.io.ByteArrayOutputStream;    import java.io.File;    import java.io.FileOutputStream;    import java.io.IOException;    import java.net.URL;    import java.net.URLConnection;    import java.security.MessageDigest;    import android.graphics.Bitmap;    import android.graphics.BitmapFactory;    import android.os.Environment;    import android.os.Handler;    import android.os.Message;    import android.util.Log;        public class ImageUtil {        private static final String SDCARD_CACHE_IMG_PATH = Environment                .getExternalStorageDirectory().getPath() + "/itcast/images/";            /**        * 保存图片到SD卡        * @param imagePath        * @param buffer        * @throws IOException        */        public static void saveImage(String imagePath, byte[] buffer)                throws IOException {            File f = new File(imagePath);            if (f.exists()) {                return;            } else {                File parentFile = f.getParentFile();                if (!parentFile.exists()) {                    parentFile.mkdirs();                }                f.createNewFile();                FileOutputStream fos = new FileOutputStream(imagePath);                fos.write(buffer);                fos.flush();                fos.close();            }        }                /**        * 从SD卡加载图片        * @param imagePath        * @return        */        public static Bitmap getImageFromLocal(String imagePath){            File file = new File(imagePath);            if(file.exists()){                Bitmap bitmap = BitmapFactory.decodeFile(imagePath);                file.setLastModified(System.currentTimeMillis());                return bitmap;            }                return null;        }                /**        * Bitmap转换到Byte[]        * @param bm        * @return        */        public static byte[] bitmap2Bytes(Bitmap bm){               ByteArrayOutputStream bas = new ByteArrayOutputStream();                 bm.compress(Bitmap.CompressFormat.JPEG, 100, bas);                 return bas.toByteArray();              }                  /**        * 从本地或者服务端加载图片        * @return        * @throws IOException         */        public static Bitmap loadImage(final String imagePath,final String imgUrl,final ImageCallback callback) {            Bitmap bitmap = getImageFromLocal(imagePath);            if(bitmap != null){                return bitmap;            }else{//从网上加载                final Handler handler = new Handler(){                    @Override                    public void handleMessage(Message msg) {                        if(msg.obj!=null){                            Bitmap bitmap = (Bitmap) msg.obj;                            callback.loadImage(bitmap, imagePath);                        }                    }                };                                Runnable runnable = new Runnable() {                    @Override                    public void run() {                        try {                            URL url = new URL(imgUrl);                            Log.e("图片加载", imgUrl);                            URLConnection conn = url.openConnection();                            conn.connect();                            BufferedInputStream bis = new BufferedInputStream(conn.getInputStream(),8192) ;                            Bitmap bitmap = BitmapFactory.decodeStream(bis);                            //保存文件到sd卡                            saveImage(imagePath,bitmap2Bytes(bitmap));                            Message msg = handler.obtainMessage();                            msg.obj = bitmap;                            handler.sendMessage(msg);                        } catch (IOException e) {                            Log.e(ImageUtil.class.getName(), "保存图片到本地存储卡出错！");                        }                    }                };                ThreadPoolManager.getInstance().addTask(runnable);            }            return null;        }            // 返回图片存到sd卡的路径        public static String getCacheImgPath() {            return SDCARD_CACHE_IMG_PATH;        }            public static String md5(String paramString) {            String returnStr;            try {                MessageDigest localMessageDigest = MessageDigest.getInstance("MD5");                localMessageDigest.update(paramString.getBytes());                returnStr = byteToHexString(localMessageDigest.digest());                return returnStr;            } catch (Exception e) {                return paramString;            }        }            /**        * 将指定byte数组转换成16进制字符串        *         * @param b        * @return        */        public static String byteToHexString(byte[] b) {            StringBuffer hexString = new StringBuffer();            for (int i = 0; i < b.length; i++) {                String hex = Integer.toHexString(b[i] & 0xFF);                if (hex.length() == 1) {                    hex = '0' + hex;                }                hexString.append(hex.toUpperCase());            }            return hexString.toString();        }                /**        *         * @author Mathew        *        */        public interface ImageCallback{            public void loadImage(Bitmap bitmap,String imagePath);        }            }