/**
 * 将 数据库从 assets 复制到 databases下
 */
private void copyDB() {
 //data/data/packageName/databases/
 File mkdir = new File(getFilesDir().getParent(),"databases");
 //创建 databases文件夹
 if (!mkdir.exists()) mkdir.mkdirs();
 Log.e(TAG, "copyDb: mkdir="+mkdir.getPath());
 //数据库文件
 File file = new File(mkdir,"SinBusinessWssm1.db");
 //只是在程序第一次启动时创建
 if(!file.exists()){
  //获取 assets管理
  AssetManager assets = getAssets();
  //执行文件复制
  try {
   InputStream open = assets.open("SinBusinessWssm1.db");
   FileOutputStream fos = new FileOutputStream(file);
   byte[] bs = new byte[1024];
   int len ;
   while ((len = open.read(bs))!=-1){
    fos.write(bs,0,len);
   }
   fos.flush();
   fos.close();
   open.close();
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
 Log.e(TAG, "copyDb: exists="+file.getPath());
}