package com.test.db;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;

public class DbtestActivity extends Activity {
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.main);

 // com.test.db 是程序的包名，請根據(jù)自己的程序調(diào)整
 // /data/data/com.test.db/
 // databases 目錄是準(zhǔn)備放 SQLite 數(shù)據(jù)庫的地方，也是 Android 程序默認(rèn)的數(shù)據(jù)庫存儲目錄
 // 數(shù)據(jù)庫名為 test.db
 String DB_PATH = "/data/data/com.test.db/databases/";
 String DB_NAME = "test.db";

 // 檢查 SQLite 數(shù)據(jù)庫文件是否存在
 if ((new File(DB_PATH + DB_NAME)).exists() == false) {
  // 如 SQLite 數(shù)據(jù)庫文件不存在，再檢查一下 database 目錄是否存在
  File f = new File(DB_PATH);
  // 如 database 目錄不存在，新建該目錄
  if (!f.exists()) {
  f.mkdir();
  }

  try {
  // 得到 assets 目錄下我們實現(xiàn)準(zhǔn)備好的 SQLite 數(shù)據(jù)庫作為輸入流
  InputStream is = getBaseContext().getAssets().open(DB_NAME);
  // 輸出流
  OutputStream os = new FileOutputStream(DB_PATH + DB_NAME);

  // 文件寫入
  byte[] buffer = new byte[1024];
  int length;
  while ((length = is.read(buffer)) > 0) {
   os.write(buffer, 0, length);
  }

  // 關(guān)閉文件流
  os.flush();
  os.close();
  is.close();
  } catch (Exception e) {
  e.printStackTrace();
  }
 }

 // 下面測試 /data/data/com.test.db/databases/ 下的數(shù)據(jù)庫是否能正常工作
 SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(DB_PATH + DB_NAME, null);
 Cursor cursor = database.rawQuery("select * from test", null);

 if (cursor.getCount() > 0) {
  cursor.moveToFirst();
  try {
  // 解決中文亂碼問題
  byte test[] = cursor.getBlob(0);
  String strtest = new String(test, "utf-8").trim();

  // 看輸出的信息是否正確
  System.out.println(strtest);
  } catch (UnsupportedEncodingException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
  }
 }
 cursor.close();
 }
}

package zcping.syan.DBDefinition;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import zcping.syan.DragonBaby.R;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;

public class ReleaseDataBaseActivity{
 /** Called when the activity is first created. */
 //SD卡下的目錄
 private final String DATABASE_PATH = android.os.Environment
  .getExternalStorageDirectory().getAbsolutePath() + "/db_exam";
 //數(shù)據(jù)庫名
 private final String DATABASE_FILENAME = "db_exam.db";
 //這個context是必需的，沒有context，怎么都不能實現(xiàn)數(shù)據(jù)庫的拷貝操作；
 private Context context;
 //構(gòu)造函數(shù)必需傳入Context，數(shù)據(jù)庫的操作都帶有這個參數(shù)的傳入
 public ReleaseDataBaseActivity(Context ctx) {
 this.context = ctx;
 }

 public SQLiteDatabase OpenDataBase() {
 try {
  String databaseFilename = DATABASE_PATH + "/" + DATABASE_FILENAME;
  File dir = new File(DATABASE_PATH);
  //判斷SD卡下是否存在存放數(shù)據(jù)庫的目錄，如果不存在，新建目錄
  if (!dir.exists()) {
  dir.mkdir();
  Log.i("ReleaseDataBaseActivity", "dir made:" + DATABASE_PATH);
  } else {
  Log.i("ReleaseDataBaseActivity", "dir exist:" + DATABASE_PATH);
  }
  try {
  //如果數(shù)據(jù)庫已經(jīng)在SD卡的目錄下存在，那么不需要重新創(chuàng)建，否則創(chuàng)建文件，并拷貝/res/raw下面的數(shù)據(jù)庫文件
  if (!(new File(databaseFilename)).exists()) {
   Log.i("ReleaseDataBaseActivity", "file not exist:"
    + databaseFilename);
   ///res/raw數(shù)據(jù)庫作為輸出流
   InputStream is = this.context.getResources().openRawResource(
    R.raw.db_exam);
   //測試用
   int size = is.available();
   Log.i( "ReleaseDataBaseActivity", "DATABASE_SIZE:" + 1 );
   Log.i("ReleaseDataBaseActivity", "count:" + 0);
   //用于存放數(shù)據(jù)庫信息的數(shù)據(jù)流
   FileOutputStream fos = new FileOutputStream(
    databaseFilename);
    byte[] buffer = new byte[8192];
   int count = 0;
   Log.i("ReleaseDataBaseActivity", "count:" + count);
   //把數(shù)據(jù)寫入SD卡目錄下
   while ((count = is.read(buffer)) > 0) {
   fos.write(buffer, 0, count);
   }
   fos.flush();
   fos.close();
   is.close();
  }
  } catch (FileNotFoundException e) {
  Log.e("Database", "File not found");
  e.printStackTrace();
  } catch (IOException e) {
  Log.e("Database", "IO exception");
  e.printStackTrace();
  }
  //實例化sd卡上得數(shù)據(jù)庫，database作為返回值，是后面所有插入，刪除，查詢操作的借口。
  SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(
   databaseFilename, null);
  return database;

 } catch (Exception e) {
 }
 return null;
 }
}