在android中备份/恢复sqlite db [英] Backup/restore sqlite db in android

问题描述

可能的重复:
Android 备份/恢复:如何备份内部数据库?

我正在开发一个包含 SQL lite db 的应用程序.我需要让用户能够备份数据库并再次恢复它.我怎样才能做到这一点?示例代码?

I am developing an app in which there is SQL lite db. I need to give the user the ability to back up the database and restore it again. How can I do that? Sample code?

如果我的用户保存了数据库，然后将应用程序升级到新的数据库版本代码，恢复是否有效?我该怎么做?

And in case my user saved the db, and then upgraded the app to a new DB version code, will restore work? How do I go about that?

推荐答案

在文件夹/data/data/'your.app.package'/databases/"中有一个 .db 文件，它是你的数据库.您可以复制该文件，保存它，然后再将其放回原处.

In the folder "/data/data/'your.app.package'/databases/" you have a .db file that is your database. You can copy that file, save it, and then place it back there again.

关于如何将数据库备份到外部存储的示例:

One example on how to backup the database to the external storage:

    final String inFileName = "/data/data/<your.app.package>/databases/foo.db";
    File dbFile = new File(inFileName);
    FileInputStream fis = new FileInputStream(dbFile);

    String outFileName = Environment.getExternalStorageDirectory()+"/database_copy.db";

    // Open the empty db as the output stream
    OutputStream output = new FileOutputStream(outFileName);

    // Transfer bytes from the inputfile to the outputfile
    byte[] buffer = new byte[1024];
    int length;
    while ((length = fis.read(buffer))>0){
        output.write(buffer, 0, length);
    }

    // Close the streams
    output.flush();
    output.close();
    fis.close();

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