android如何导出数据库到SD卡

package com.digitnexus.scv.util;

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

import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.res.AssetManager;
import android.os.Environment;
import android.util.Log;

import com.digitnexus.core.util.sdcard.SDCardUtil;

public class ImportDBFile {

   	private final String TAG = ImportDBFile.class.getSimpleName() ; 
	private final int BUFFER_SIZE = 40*1024;
	public String DB_NAME = "scv.db"; // save db file name
	public String PACKAGE_NAME = null;
	public String DB_PATH = "/data" + Environment.getDataDirectory().getAbsolutePath() ;
	
	public final String Package_path = Environment.getExternalStorageState() ;

	private Context context;
	
	
	public ImportDBFile(){}

	public ImportDBFile(Context context, String dbName) {
		this.context = context;
		DB_NAME = dbName ; 
	}

	public void openDatabase() {
		ApplicationInfo applicationInfo = context.getApplicationInfo() ;
		PACKAGE_NAME = applicationInfo.packageName ;
		copyDataBaseToAPP(DB_PATH +"/"+ PACKAGE_NAME +"/databases/" + DB_NAME);
	}

	private void copyDataBaseToAPP(String dbfile) {
		try {
		   	// if the db file does not exist, first import the db file
			if (!(new File(dbfile).exists())) {
				File file = new File(dbfile.substring(0, dbfile.lastIndexOf("/"))) ;
				file.mkdirs();
				System.out.println("Create database directory successed!");
				file.createNewFile() ;
				AssetManager am =  null ;    
				am = this.context.getAssets();    
				InputStream is = am.open(DB_NAME);    // to import the db file
				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();
				Log.i(TAG, "import " + DB_NAME + "successful!") ;
			}
		} catch (FileNotFoundException e) {
			Log.e("Database", "File not found");
			e.printStackTrace();
		} catch (IOException e) {
			Log.e("Database", "IO exception");
			e.printStackTrace();
		}
	}
	
	public void exportDBToSDCard(){
		ApplicationInfo applicationInfo = context.getApplicationInfo() ;
		PACKAGE_NAME = applicationInfo.packageName ;
		String path = DB_PATH +"/"+ PACKAGE_NAME +"/databases/" + DB_NAME ;
		try {
			FileInputStream fis = new FileInputStream(new File(path)) ;
			System.out.println(SDCardUtil.getSDCardPath()+"/"+DB_NAME);
			System.out.println(Environment.getExternalStorageDirectory()
					.getAbsolutePath()); ;
			FileOutputStream fos = new FileOutputStream(SDCardUtil.getSDCardPath()+"/"+DB_NAME) ;
			byte[] buffer = new byte[BUFFER_SIZE];
			int count = 0;
			while ((count = fis.read(buffer)) > 0) {
				fos.write(buffer, 0, count);
			}
			fos.close();
			fis.close();
			System.out.println("import to sdcard success!");
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		
	}
}