如何导入已有数据库
//我已经有数据库了，如何导入并查询呢
滄梧
2020-01-18
1 回答
操作方法：1. 把原数据库包括在项目源码的 res/raw 目录下，然后建立一个DBManager类，代码如下：
| 12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758 | 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"; //保存的数据库文件名 public static final String PACKAGE_NAME = "com.android.ImportDatabase"; public static final String DB_PATH = "/data" + Environment.getDataDirectory().getAbsolutePath() + "/" + PACKAGE_NAME; //在手机里存放数据库的位置 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())) { //判断数据库文件是否存在，若不存在则执行导入，否则直接打开数据库 InputStream is = this.context.getResources().openRawResource( R.raw.countries); //欲导入的数据库 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; } |
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