09-18 16:57:23.045: W/System.err(2414): java.io.FileNotFoundException: /storage/emulated/0/download/V2.2.0: open failed: EACCES (Permission denied)

09-18 16:57:23.046: W/System.err(2414):  at libcore.io.IoBridge.open(IoBridge.java:487)

09-18 16:57:23.046: W/System.err(2414):  at java.io.FileOutputStream.<init>(FileOutputStream.java:87)

09-18 16:57:23.046: W/System.err(2414):  at java.io.FileOutputStream.<init>(FileOutputStream.java:72)

09-18 16:57:23.046: W/System.err(2414):  at com.xuecheng.dust.update2.UpdateManager$downloadApkThread.run(UpdateManager.java:347)

09-18 16:57:23.046: W/System.err(2414): Caused by: android.system.ErrnoException: open failed: EACCES (Permission denied)

09-18 16:57:23.046: W/System.err(2414):  at libcore.io.Posix.open(Native Method)

09-18 16:57:23.046: W/System.err(2414):  at libcore.io.BlockGuardOs.open(BlockGuardOs.java:186)

09-18 16:57:23.046: W/System.err(2414):  at libcore.io.IoBridge.open(IoBridge.java:473)

看到这肯定可以断定是没有加权限，随手把读和写的权限加上了：

 <!--在SD卡中创建与删除文件权限 -->

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

<!--向SD卡写入数据的权限 -->

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

<!-- 读取数据的权限 -->

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

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

编译的时候还是出现同样的问题；经过查询资料发现：

SDK1.5需要android.permission.GET_TASKS权限判断本程序是否为当前运行的应用?

所以又把TASKS权限添加上，就可以运行写的升级程序了

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

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

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

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

原文链接：http://www.apkbus.com/blog-784586-61759.html