我看过几篇关于如何在android中导入和导出数据库的帖子,我找到了这些代码,但我似乎无法使它工作.我收到错误java.io.filenotfoundexception / storage / sdcard0 / BackupFolder / DatabaseName:打开失败的ENOENT(没有这样的文件或目录).我改变了一些东西,但我仍然没有找到文件异常
这是我的出口:
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();
}
}
和我的导入:
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();
}
}
解决方法:
功能声明 –
try {
backupDatabase();
} catch (IOException e1) {
// Todo Auto-generated catch block
e1.printstacktrace();
}
功能定义 –
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();
}
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