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; /** * 将把assets下的数据库文件直接复制到DB_PATH，但数据库文件大小限制在1M以下 * 如果有超过1M的大文件，则需要先分割为N个小文件，然后使用copyBigDatabase()替换copyDatabase() */ public class DBManager extends SQLiteOpenHelper { // 用户数据库文件的版本 private static final int DB_VERSION = 1; // 数据库文件目标存放路径为系统默认位置，com.rys.lb 是你的包名 private static String DB_PATH = "/data/data/com.chishacai/"; // 如果你想把数据库文件存放在SD卡的话 // 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; /** * 如果数据库文件较大，使用FileSplit分割为小于1M的小文件 此例中分割为 data.db.100 data.db.101 * data.db.102.... */ // 第一个文件名后缀 private static final int ASSETS_SUFFIX_BEGIN = 0; // 最后一个文件名后缀 private static final int ASSETS_SUFFIX_END = 3; private static SQLiteDatabase credb ; /** * 在SQLiteOpenHelper的子类当中，必须有该构造函数 * @param context 上下文对象 * @param name 数据库名称 * @param factory 一般都是null * @param version 当前数据库的版本，值必须是整数并且是递增的状态 */ public DBManager(Context context, String name, CursorFactory factory, int version) { // 必须通过super调用父类当中的构造函数 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) { // 数据库已存在，do nothing. System.out.println("数据库已经存在"); } else { // 创建数据库 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); // 复制asseets中的db文件到DB_PATH下 // copyDataBase(); copyBigDataBase(); } catch (IOException e) { throw new Error("数据库创建失败"); } } } // 检查数据库是否有效 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("关闭"); } return checkDB != null ? true : false; } public DBManager open1() { String myPath = DB_PATH + DB_NAME; System.out.println("数据库已经..."); myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); System.out.println("数据库打开"); 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(); } // 复制assets下的大数据库文件时用这个 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("数据库已经复制"); } /** * 关闭刚创建的数据库 */ public void closedb() { if(credb != null) { credb.close() ; System.out.println("创建的数据库已关闭"); } } @Override public synchronized void close() { if (myDataBase != null) { myDataBase.close(); System.out.println("关闭成功1"); } super.close(); System.out.println("关闭成功2"); } /** * 该函数是在第一次创建的时候执行， 实际上是第一次得到SQLiteDatabase对象的时候才会调用这个方法 */ @Override public void onCreate(SQLiteDatabase db) { } /** * 数据库表结构有变化时采用 */ @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; } }
改了一点点东西，代码的注释就能看懂。
1.如果数据库文件大于1M，就用Filesplit工具切割。先去下载这个软件工具
2.首先把已有的数据库放到assets文件夹下面，如果没有这个文件就先在android项目中建立这个文件夹。