Android中怎么保證數據同步寫入磁盤

這期內容當中小編將會給大家帶來有關Android中怎么保證數據同步寫入磁盤，文章內容豐富且以專業的角度為大家分析和敘述，閱讀完這篇文章希望大家可以有所收獲。

在一些特定的工作場景中，我們把數據及時寫出磁盤，而不是暫時保存在系統的文件緩存區，防止掉電導致數據丟失

/** * Force all system buffers to synchronize with the underlying * device. This method returns after all modified data and * attributes of this FileDescriptor have been written to the * relevant device(s). In particular, if this FileDescriptor * refers to a physical storage medium, such as a file in a file * system, sync will not return until all in-memory modified copies * of buffers associated with this FileDescriptor have been * written to the physical medium. * * sync is meant to be used by code that requires physical * storage (such as a file) to be in a known state For * example, a class that provided a simple transaction facility * might use sync to ensure that all changes to a file caused * by a given transaction were recorded on a storage medium. * * sync only affects buffers downstream of this FileDescriptor. If * any in-memory buffering is being done by the application (for * example, by a BufferedOutputStream object), those buffers must * be flushed into the FileDescriptor (for example, by invoking * OutputStream.flush) before that data will be affected by sync. * * @exception SyncFailedException *    Thrown when the buffers cannot be flushed, *    or because the system cannot guarantee that all the *    buffers have been synchronized with physical media. * @since   JDK1.1 */public native void sync() throws SyncFailedException;

可能一看到這個場景，很多人會想到數據庫的事務，查看Android數據庫sqlite的源碼可以看到，數據庫事務只能保證n個操作，要么都執行，要么都不執行。數據庫事務在所有操作完成后，會提醒文件系統與磁盤同步，但是不會等到所有系統緩沖區與磁盤同步完成才返回！

FileDescriptor.getFd().sync();會強制所有系統緩沖區與磁盤同步File file = new File("/sdcard/a.txt");    try {      FileOutputStream outputStream = new FileOutputStream(file);      outputStream.write("kuangxf".getBytes());      outputStream.flush();      //強制文件系統刷新      outputStream.getFD().sync();    } catch (Exception e) {      e.printStackTrace();    }

上述就是小編為大家分享的Android中怎么保證數據同步寫入磁盤了，如果剛好有類似的疑惑，不妨參照上述分析進行理解。如果想知道更多相關知識，歡迎關注億速云行業資訊頻道。