import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteException;import android.database.sqlite.SQLiteOpenHelper;/** * 將把assets下的資料庫檔案直接複製到DB_PATH,但資料庫檔案大小限制在1M以下 * 如果有超過1M的大檔案,則需要先分割為N個小檔案,然後使用copyBigDatabase()替換copyDatabase() */public class DBManager extends SQLiteOpenHelper { // 使用者資料庫檔案的版本 private static final int DB_VERSION = 1; // 資料庫檔案目標存放路徑為系統預設位置,com.rys.lb 是你的包名 private static String DB_PATH = "/data/data/com.chishacai/"; // 如果你想把資料庫檔案存放在SD卡的話 // private static String DB_PATH = // android.os.Environment.getExternalStorageDirectory().getAbsolutePath() // + "/arthurcn/drivertest/packfiles/"; private static String DB_NAME = "cscpb.db"; private static String ASSETS_NAME = "cscdb/cscpb.db"; private SQLiteDatabase myDataBase; private final Context myContext; /** * 如果資料庫檔案較大,使用FileSplit分割為小於1M的小檔案 此例中分割為 data.db.100 data.db.101 * data.db.102.... */ // 第一個檔案名稱尾碼 private static final int ASSETS_SUFFIX_BEGIN = 0; // 最後一個檔案名稱尾碼 private static final int ASSETS_SUFFIX_END = 3; private static SQLiteDatabase credb ; /** * 在SQLiteOpenHelper的子類當中,必須有該建構函式 * @param context 內容物件 * @param name 資料庫名稱 * @param factory 一般都是null * @param version 當前資料庫的版本,值必須是整數並且是遞增的狀態 */ public DBManager(Context context, String name, CursorFactory factory, int version) { // 必須通過super調用父類當中的建構函式 super(context, name, null, version); this.myContext = context; } public DBManager(Context context, String name, int version) { this(context, name, null, version); } public DBManager(Context context, String name) { this(context, name, DB_VERSION); } public DBManager(Context context) { this(context, DB_PATH + DB_NAME); } public void createDataBase() throws IOException { boolean dbExist = checkDataBase(); if (dbExist) { // 資料庫已存在,do nothing. System.out.println("資料庫已經存在"); } else { // 建立資料庫 try { File dir = new File(DB_PATH); if (!dir.exists()) { dir.mkdirs(); } File dbf = new File(DB_PATH + DB_NAME); if (dbf.exists()) { dbf.delete(); } credb = SQLiteDatabase.openOrCreateDatabase(dbf, null); // 複製asseets中的db檔案到DB_PATH下 // copyDataBase(); copyBigDataBase(); } catch (IOException e) { throw new Error("資料庫建立失敗"); } } } // 檢查資料庫是否有效 private boolean checkDataBase() { SQLiteDatabase checkDB = null; String myPath = DB_PATH + DB_NAME; try { checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); } catch (SQLiteException e) { // database does't exist yet. } if (checkDB != null) { checkDB.close(); System.out.println("關閉"); } return checkDB != null ? true : false; } public DBManager open1() { String myPath = DB_PATH + DB_NAME; System.out.println("資料庫已經..."); myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); System.out.println("資料庫開啟"); return this; } /** * Copies your database from your local assets-folder to the just created * empty database in the system folder, from where it can be accessed and * handled. This is done by transfering bytestream. * */ private void copyDataBase() throws IOException { // Open your local db as the input stream InputStream myInput = myContext.getAssets().open(ASSETS_NAME); // Path to the just created empty db String outFileName = DB_PATH + DB_NAME; // Open the empty db as the output stream OutputStream myOutput = new FileOutputStream(outFileName); // transfer bytes from the inputfile to the outputfile byte[] buffer = new byte[1024]; int length; while ((length = myInput.read(buffer)) > 0) { myOutput.write(buffer, 0, length); } // Close the streams myOutput.flush(); myOutput.close(); myInput.close(); } // 複製assets下的大資料庫檔案時用這個 private void copyBigDataBase() throws IOException { InputStream myInput; String outFileName = DB_PATH + DB_NAME; OutputStream myOutput = new FileOutputStream(outFileName); for (int i = ASSETS_SUFFIX_BEGIN; i < ASSETS_SUFFIX_END + 1; i++) { myInput = myContext.getAssets().open(ASSETS_NAME + "." + i); byte[] buffer = new byte[1024]; int length; while ((length = myInput.read(buffer)) > 0) { myOutput.write(buffer, 0, length); } myOutput.flush(); myInput.close(); } myOutput.close(); System.out.println("資料庫已經複製"); } /** * 關閉剛建立的資料庫 */ public void closedb() { if(credb != null) { credb.close() ; System.out.println("建立的資料庫已關閉"); } } @Override public synchronized void close() { if (myDataBase != null) { myDataBase.close(); System.out.println("關閉成功1"); } super.close(); System.out.println("關閉成功2"); } /** * 該函數是在第一次建立的時候執行, 實際上是第一次得到SQLiteDatabase對象的時候才會調用這個方法 */ @Override public void onCreate(SQLiteDatabase db) { } /** * 資料庫表結構有變化時採用 */ @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { } public void open() { SQLiteDatabase DataBase = this.openOrCreateDatabase("data.db", null); } private SQLiteDatabase openOrCreateDatabase(String string, Object object) { // TODO Auto-generated method stub return null; }}
改了一點點東西,代碼的注釋就能看懂。
1.如果資料庫檔案大於1M,就用Filesplit工具切割。先去下載這個軟體工具2.首先把已有的資料庫放到assets檔案夾下面,如果沒有這個檔案就先在android項目中建立這個檔案夾。