android 读取本地数据库db文件（Android sqlite）

在Android中，要读取本地的.db文件并使用SQLite数据库，你可以按照以下步骤操作：

1. 将.db文件放置在Android项目的assets文件夹中。
2. 使用SQLiteOpenHelper或SQLiteDatabase打开和查询该数据库文件。

以下是一个简单的例子，演示如何读取位于assets文件夹中的example.db文件：

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
 
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
 
public class DatabaseHelper extends SQLiteOpenHelper {
 
    private static String DB_PATH = "";
    private static String DB_NAME = "example.db";
    private final Context mContext;
    private SQLiteDatabase mDataBase;
 
    public DatabaseHelper(Context context) {
        super(context, DB_NAME, null, 1); // 1 is the database version
        this.mContext = context;
        DB_PATH = context.getApplicationInfo().dataDir + "/databases/";
        try {
            createDataBase();
            openDataBase();
        } catch (IOException e) {
            throw new Error("ErrorCopyingDataBase");
        }
    }
 
    private void createDataBase() throws IOException {
        boolean dbExist = checkDataBase();
        if (dbExist) {
            // do nothing - database already exist
        } else {
            // By calling this method and passing in the name of our db file,
            // it will check to see if there is a database by that name in
            // our assets folder. If not, it doesn't overwrite.
            this.getReadableDatabase();
            try {
                copyDataBase();
            } catch (IOException e) {
                throw new Error("ErrorCopyingDataBase");
            }
        }
    }
 
    private boolean checkDataBase() {
        File dbFile = new File(DB_PATH + DB_NAME);
        return dbFile.exists();
    }
 
    private void copyDataBase() throws IOException {
        InputStream mInput = mContext.getAssets().open(DB_NAME);
        OutputStream mOu