我见过如何导入和导出的android数据库中的几个帖子，我发现这些code，但我似乎无法使它发挥作用。我得到的错误java.io.filenotfoundexception /存储/ sdcard0 / BackupFolder /数据库名：打开失败ENOENT（没有这样的文件或目录）。香港专业教育学院改变了一些东西，但我仍然没有得到文件中发现异常

这是我的出口：

 私人无效exportDB（）{
        尝试 {
             db.open（）;
             文件NEWFILE =新的文件（/ SD卡/ myexport）;
            输入的InputStream =新的FileInputStream（
            /data/data/com.example.mycarfuel/data

基地/ MyDatabase的）;

                的OutputStream输出=新的FileOutputStream（NEWFILE）;
                byte []的缓冲区=新的字节[1024];
                INT长;
                而（（长度= input.read（缓冲液））大于0）{
                    output.write（缓冲液，0，长度）;
                }
                output.flush（）;
                output.close（）;
                input.close（）;
                db.close（）;

            }赶上（FileNotFoundException异常E1）{
                // TODO自动生成的catch块
                e1.printStackTrace（）;
            }赶上（IOException异常E）{
                // TODO自动生成的catch块
                e.printStackTrace（）;
            }
}
 

和我的导入：

 私人无效importDB（）{
        尝试 {
            文件SD = Environment.getExternalStorageDirectory（）;
            文件数据= Environment.getDataDirectory（）;

            如果（sd.canWrite（））{
                字符串currentDBPath =//数据//+包名
                        +//数据库//+数据库名;
                    字符串backupDBPath =/ BackupFolder /数据库名

;
                文件的某个backupdb =新的文件（数据，currentDBPath）;
                文件currentDB =新的文件（SD，backupDBPath）;

                FileChannel SRC =新的FileInputStream（currentDB）.getChannel（）;
                FileChannel DST =新的FileOutputStream（某个backupdb）.getChannel（）;
                dst.transferFrom（源，0，src.size（））;
                src.close（）;
                dst.close（）;
                Toast.makeText（getBaseContext（），backupDB.toString（），


Toast.LENGTH_LONG）.show（）;
        }
    }赶上（例外五）{
        Toast.makeText（getBaseContext（），e.​​toString（），Toast.LENGTH_LONG）
                。显示（）;
    }
}
 

解决方案

SQLite数据库到本地文件系统 -

函数声明 -

 尝试{
            backupDatabase（）;
        }赶上（IOException异常E1）{
            // TODO自动生成的catch块
            e1.printStackTrace（）;
        }
 

功能定义 -

 公共静态无效backupDatabase（）抛出IOException异常{
        //打开本地数据库作为输入流
        字符串inFileName =/data/data/com.myapp.main/databases/MYDB;
        文件DBFILE =新的文件（inFileName）;
        的FileInputStream FIS =新的FileInputStream（DBFILE）;

        字符串outFileName = Environment.getExternalStorageDirectory（）+/ MYDB;
        //打开空分贝的输出流
        的OutputStream输出=新的FileOutputStream（outFileName）;
        //传输的字节从inputfile中的OUTPUTFILE
        byte []的缓冲区=新的字节[1024];
        INT长;
        而（（长度= fis.read（缓冲液））大于0）{
            output.write（缓冲液，0，长度）;
        }
        //关闭流
        output.flush（）;
        output.close（）;
        fis.close（）;
    }
 

Ive seen a few posts on how to import and export a database in android and i found these code, but i cant seem to make it work. I get the error java.io.filenotfoundexception /storage/sdcard0/BackupFolder/DatabaseName:open failed ENOENT (no such file or directory). Ive changed a few things but i still get no file found exception

here is my export:

private void exportDB() {
        try {
             db.open();
             File newFile = new File("/sdcard/myexport");
            InputStream input = new FileInputStream(
            "/data/data/com.example.mycarfuel/data

bases/MyDatabase");

                OutputStream output = new FileOutputStream(newFile);
                byte[] buffer = new byte[1024];
                int length;
                while ((length = input.read(buffer)) > 0) {
                    output.write(buffer, 0, length);
                }
                output.flush();
                output.close();
                input.close();
                db.close();

            } catch (FileNotFoundException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
}

and my import:

private void importDB() {
        try {
            File sd = Environment.getExternalStorageDirectory();
            File data = Environment.getDataDirectory();

            if (sd.canWrite()) {
                String currentDBPath = "//data//" + "PackageName"
                        + "//databases//" + "DatabaseName";
                    String backupDBPath = "/BackupFolder/DatabaseName

";
                File backupDB = new File(data, currentDBPath);
                File currentDB = new File(sd, backupDBPath);

                FileChannel src = new FileInputStream(currentDB).getChannel();
                FileChannel dst = new FileOutputStream(backupDB).getChannel();
                dst.transferFrom(src, 0, src.size());
                src.close();
                dst.close();
                Toast.makeText(getBaseContext(), backupDB.toString(),


Toast.LENGTH_LONG).show();
        }
    } catch (Exception e) {
        Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG)
                .show();
    }
}

SQlite database to our local file system-

Function declaration-

        try {
            backupDatabase();
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }

Function defined-

public static void backupDatabase() throws IOException {
        //Open your local db as the input stream
        String inFileName = "/data/data/com.myapp.main/databases/MYDB";
        File dbFile = new File(inFileName);
        FileInputStream fis = new FileInputStream(dbFile);

        String outFileName = Environment.getExternalStorageDirectory()+"/MYDB";
        //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();
    }