android 导入外部数据库注意事项

在androidstudio中，可以把db文件放在assets文件夹下（在main下创建）

在将db导入时注意要先创建对应的文件夹，否则会报错

new File(DB_PATH).mkdirs();
File dbFile=new File(dbfileString);
if (dbFile.exists()){
dbFile.delete();
}
try {
dbFile.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}

public class ImportDB {
private final int BUFFER_SIZE = 10000;
public static final String DB_NAME = "ChinaCity"; //保存的数据库文件名
public static final String PACKAGE_NAME = "com.mapplication";//工程包名
public static final String DB_PATH = "/data"
+ Environment.getDataDirectory().getAbsolutePath() + "/"
+ PACKAGE_NAME + "/databases"; //在手机里存放数据库的位置--/data/data/com.zhaninternship.mapplication/databases/ChinaCity
private Context context;

public ImportDB(Context context) {
this.context = context;
}

public void copyDatabase() {
String dbfileString = DB_PATH + "/" + DB_NAME;
new File(DB_PATH).mkdirs();
File dbFile=new File(dbfileString);
if (dbFile.exists()){
dbFile.delete();
}
try {
dbFile.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}

try {
InputStream is = this.context.getClass().getClassLoader().getResourceAsStream("assets/" + "ChinaCity.db");
FileOutputStream fos = new FileOutputStream(dbfileString);
byte[] buffer = new byte[BUFFER_SIZE];
int count=0;
while((count=is.read(buffer))>0){
fos.write(buffer, 0, count);
}
fos.flush();
fos.close();//关闭输出流
is.close();//关闭输入流
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}