Android获取文件的MD5值

2/10/2017来源:ASP.NET技巧人气:432

package my.bag;

import java.io.File; import java.io.FileInputStream; import java.math.BigInteger; import java.security.MessageDigest; import java.util.HashMap; import java.util.Map;

import Android.app.Activity; import android.os.Bundle; import android.util.Log;

public class FileDigest extends Activity {  @Override  PRotected void onCreate(Bundle savedInstanceState) {   // TODO Auto-generated method stub   super.onCreate(savedInstanceState);   File file = new File("/mnt/sdcard/123.txt");   Log.e("md5", getFileMD5(file));  }

 /**   * 获取单个文件的MD5值!

  * @param file   * @return   */

 public static String getFileMD5(File file) {   if (!file.isFile()) {    return null;   }   MessageDigest digest = null;   FileInputStream in = null;   byte buffer[] = new byte[1024];   int len;   try {    digest = MessageDigest.getInstance("MD5");    in = new FileInputStream(file);    while ((len = in.read(buffer, 0, 1024)) != -1) {     digest.update(buffer, 0, len);    }    in.close();   } catch (Exception e) {    e.printStackTrace();    return null;   }   BigInteger bigInt = new BigInteger(1, digest.digest());   return bigInt.toString(16);  }

 /**   * 获取文件夹中文件的MD5值   *   * @param file   * @param listChild   *            ;true递归子目录中的文件   * @return   */  public static Map<String, String> getDirMD5(File file, boolean listChild) {   if (!file.isDirectory()) {    return null;   }   Map<String, String> map = new HashMap<String, String>();   String md5;   File files[] = file.listFiles();   for (int i = 0; i < files.length; i++) {    File f = files[i];    if (f.isDirectory() && listChild) {     map.putAll(getDirMD5(f, listChild));    } else {     md5 = getFileMD5(f);     if (md5 != null) {      map.put(f.getPath(), md5);     }    }   }   return map;  }

}

最后不要忘了在manifest中添加权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>