如何導(dǎo)入已有數(shù)據(jù)庫
//我已經(jīng)有數(shù)據(jù)庫了，如何導(dǎo)入并查詢呢
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2020-01-18
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2020-06-08
操作方法：1. 把原數(shù)據(jù)庫包括在項目源碼的 res/raw 目錄下，然后建立一個DBManager類，代碼如下：
package?com.android.ImportDatabase;?import?java.io.File;import?java.io.FileNotFoundException;import?java.io.FileOutputStream;import?java.io.IOException;import?java.io.InputStream;?import?android.content.Context;import?android.database.sqlite.SQLiteDatabase;import?android.os.Environment;import?android.util.Log;?public?class?DBManager {????private?final?int?BUFFER_SIZE =400000;????public?static?final?String DB_NAME ="countries.db";//保存的數(shù)據(jù)庫文件名????public?static?final?String PACKAGE_NAME ="com.android.ImportDatabase";????public?static?final?String DB_PATH ="/data"????????????+ Environment.getDataDirectory().getAbsolutePath() +"/"????????????+ PACKAGE_NAME;?//在手機里存放數(shù)據(jù)庫的位置?????private?SQLiteDatabase database;????private?Context context;?????DBManager(Context context) {????????this.context = context;????}?????public?void?openDatabase() {????????this.database =this.openDatabase(DB_PATH +"/"?+ DB_NAME);????}?????private?SQLiteDatabase openDatabase(String dbfile) {????????try?{????????????if?(!(new?File(dbfile).exists())) {//判斷數(shù)據(jù)庫文件是否存在，若不存在則執(zhí)行導(dǎo)入，否則直接打開數(shù)據(jù)庫????????????????InputStream is =this.context.getResources().openRawResource(????????????????????????R.raw.countries);//欲導(dǎo)入的數(shù)據(jù)庫????????????????FileOutputStream fos =new?FileOutputStream(dbfile);????????????????byte[] buffer =new?byte[BUFFER_SIZE];????????????????int?count =0;????????????????while?((count = is.read(buffer)) >0) {????????????????????fos.write(buffer,0, count);????????????????}????????????????fos.close();????????????????is.close();????????????}????????????SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(dbfile,????????????????????null);????????????return?db;????????}catch?(FileNotFoundException e) {????????????Log.e("Database","File not found");????????????e.printStackTrace();????????}catch?(IOException e) {????????????Log.e("Database","IO exception");????????????e.printStackTrace();????????}????????return?null;????}