最近項目需要通過電話號碼查詢歸屬地，決定直接在本地sqlite的數據庫進行查詢，沒必要去訪問網絡(雖然最后還是決定還是將數據庫放在服務器上

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一 首先先將外部的sqlite數據庫放入assets文件夾下面

注意：

必須是sqlite數據庫(XXX.db)，如果是access(XXX.mdb)的必須進行轉換，網上有一些數據庫轉換器，或者使用SQLite Expert

二 創建AssetsDatabaseManager用來獲得操作數據庫的SQLiteDatabase

package com.ld.qmwj.dao.phonenumserach;

import java.io.File;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.io.OutputStream;

import java.util.HashMap;

import java.util.Map;

import android.content.Context;

import android.content.SharedPreferences;

import android.content.res.AssetManager;

import android.database.sqlite.SQLiteDatabase;

import android.util.Log;

/**

* This is a Assets Database Manager

* Use it, you can use a assets database file in you application

* It will copy the database file to "/data/data/[your application package name]/database" when you first time you use it

* Then you can get a SQLiteDatabase object by the assets database file

* @author RobinTang

* @time 2012-09-20

*

*

* How to use:

* 1. Initialize AssetsDatabaseManager

* 2. Get AssetsDatabaseManager

* 3. Get a SQLiteDatabase object through database file

* 4. Use this database object

*

* Using example:

* AssetsDatabaseManager.initManager(getApplication()); // this method is only need call one time

* AssetsDatabaseManager mg = AssetsDatabaseManager.getManager(); // get a AssetsDatabaseManager object

* SQLiteDatabase db1 = mg.getDatabase("db1.db"); // get SQLiteDatabase object, db1.db is a file in assets folder

* db1.??? // every operate by you want

* Of cause, you can use AssetsDatabaseManager.getManager().getDatabase("xx") to get a database when you need use a database

*/

public class AssetsDatabaseManager {

private static String tag = "QMWJ"; // for LogCat

private static String databasepath = "/data/data/%s/database"; // %s is packageName

// A mapping from assets database file to SQLiteDatabase object

private Map databases = new HashMap();

// Context of application

private Context context = null;

// Singleton Pattern

private static AssetsDatabaseManager mInstance = null;

/**

* Initialize AssetsDatabaseManager

* @param context, context of application

*/

public static void initManager(Context context){

if(mInstance == null){

mInstance = new AssetsDatabaseManager(context);

}

}

/**

* Get a AssetsDatabaseManager object

* @return, if success return a AssetsDatabaseManager object, else return null

*/

public static AssetsDatabaseManager getManager(){

return mInstance;

}

private AssetsDatabaseManager(Context context){

this.context = context;

}

/**

* Get a assets database, if this database is opened this method is only return a copy of the opened database

* @param dbfile, the assets file which will be opened for a database

* @return, if success it return a SQLiteDatabase object else return null

*/

public SQLiteDatabase getDatabase(String dbfile) {

if(databases.get(dbfile) != null){

Log.i(tag, String.format("Return a database copy of %s", dbfile));

return (SQLiteDatabase) databases.get(dbfile);

}

if(context==null)

return null;

Log.i(tag, String.format("Create database %s", dbfile));

String spath = getDatabaseFilepath();

String sfile = getDatabaseFile(dbfile);

File file = new File(sfile);

SharedPreferences dbs = context.getSharedPreferences(AssetsDatabaseManager.class.toString(), 0);

boolean flag = dbs.getBoolean(dbfile, false); // Get Database file flag, if true means this database file was copied and valid

if(!flag || !file.exists()){

file = new File(spath);

if(!file.exists() && !file.mkdirs()){

Log.i(tag, "Create \""+spath+"\" fail!");

return null;

}

if(!copyAssetsToFilesystem(dbfile, sfile)){

Log.i(tag, String.format("Copy %s to %s fail!", dbfile, sfile));

return null;

}

dbs.edit().putBoolean(dbfile, true).commit();

}

SQLiteDatabase db = SQLiteDatabase.openDatabase(sfile, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS);

if(db != null){

databases.put(dbfile, db);

}

return db;

}

private String getDatabaseFilepath(){

return String.format(databasepath, context.getApplicationInfo().packageName);

}

private String getDatabaseFile(String dbfile){

return getDatabaseFilepath()+"/"+dbfile;

}

private boolean copyAssetsToFilesystem(String assetsSrc, String des){

Log.i(tag, "Copy "+assetsSrc+" to "+des);

InputStream istream = null;

OutputStream ostream = null;

try{

AssetManager am = context.getAssets();

istream = am.open(assetsSrc);

ostream = new FileOutputStream(des);

byte[] buffer = new byte[1024];

int length;

while ((length = istream.read(buffer))>0){

ostream.write(buffer, 0, length);

}

istream.close();

ostream.close();

}

catch(Exception e){

e.printStackTrace();

try{

if(istream!=null)

istream.close();

if(ostream!=null)

ostream.close();

}

catch(Exception ee){

ee.printStackTrace();

}

return false;

}

return true;

}

/**

* Close assets database

* @param dbfile, the assets file which will be closed soon

* @return, the status of this operating

*/

public boolean closeDatabase(String dbfile){

if(databases.get(dbfile) != null){

SQLiteDatabase db = (SQLiteDatabase) databases.get(dbfile);

db.close();

databases.remove(dbfile);

return true;

}

return false;

}

/**

* Close all assets database

*/

static public void closeAllDatabase(){

Log.i(tag, "closeAllDatabase");

if(mInstance != null){

for(int i=0; i

if(mInstance.databases.get(i)!=null){

mInstance.databases.get(i).close();

}

}

mInstance.databases.clear();

}

}

}

在getDatabase中，第一次先將assets中的數據庫拷貝到當前工程下(/data/data/[your application package name]/database/數據庫名稱)

以后就可以直接在database中獲得該數據庫的SQLiteDatabase，從而進行增刪改查操作了

三 使用

// 初始化，只需要調用一次

AssetsDatabaseManager.initManager(getApplication());

// 獲取管理對象，因為數據庫需要通過管理對象才能夠獲取

AssetsDatabaseManager mg = AssetsDatabaseManager.getManager();

// 通過管理對象獲取數據庫

SQLiteDatabase db1 = mg.getDatabase("data.db");

// 對數據庫進行操作

db1.execSQL("XXXXXX");

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