在把数据库文件放在raw中，在应用程序中如何打开

时间：2021-10-01 08:21:17

1、DbManager代码

 1 package com.zyh.zyhimportdatabase;
 2 
 3 import java.io.File;
 4 import java.io.FileOutputStream;
 5 import java.io.InputStream;
 6 
 7 import android.content.Context;
 8 import android.database.sqlite.SQLiteDatabase;
 9 import android.os.Environment;
10 
11 public class DbManager {
12     private static final int BUFFER_SIZE = 1024;
13     private static final String DB_NAME = "person2.db";
14     private static final String PACKAGE_NAME = "com.zyh.zyhimportdatabase";
15     private static final String DB_PATH = "/data" + 
16     Environment.getDataDirectory().getAbsolutePath() + "/" + PACKAGE_NAME;
17     
18     private SQLiteDatabase database;
19     private Context context;
20     
21     public DbManager(Context context){
22         this.context = context;
23     }
24     
25     public void openDatabase(){
26         this.database = this.openDatabase(DB_PATH + "/" + DB_NAME);
27     }
28 
29     private SQLiteDatabase openDatabase(String dbFile) {
30         try {
31             File db_file = new File(dbFile);
32             if(!db_file.exists()){
33                 InputStream is = this.context.getResources().openRawResource(R.raw.person2);
34                 FileOutputStream fos = new FileOutputStream(dbFile);
35                 byte[] buffer = new byte[BUFFER_SIZE];
36                 int len = 0;
37                 while((len = is.read(buffer)) > 0){
38                     fos.write(buffer, 0, len);
39                 }
40                 fos.close();
41                 is.close();
42             }
43             
44             SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(db_file, null);
45             return db;
46         } catch (Exception e) {
47             // TODO Auto-generated catch block
48             e.printStackTrace();
49         }
50         return null;
51     }
52     
53     public SQLiteDatabase getDb(){
54         return this.database;
55     }
56     
57     public void closeDatabase(){
58         this.database.close();
59     }
60 }

2、activity代码

 1 package com.zyh.zyhimportdatabase;
 2 
 3 import android.os.Bundle;
 4 import android.os.Environment;
 5 import android.util.Log;
 6 import android.app.Activity;
 7 import android.database.sqlite.SQLiteDatabase;
 8 
 9 public class MainActivity extends Activity {
10 
11     @Override
12     protected void onCreate(Bundle savedInstanceState) {
13         super.onCreate(savedInstanceState);
14         setContentView(R.layout.activity_main);
15         
16         //Log.i("zyh", Environment.getDataDirectory().getAbsolutePath());
17         DbManager dbHelper = new DbManager(getApplicationContext());
18         dbHelper.openDatabase();
19         SQLiteDatabase db = dbHelper.getDb();
20         System.out.println(db.isReadOnly());
21         dbHelper.closeDatabase();
22         
23     }
24 
25 }

 上述代码的参考:http://www.cnblogs.com/xiaowenji/archive/2011/01/03/1925014.html

 

注意:A、关于对getReadableDatabase()的误区:可以参考http://blog.csdn.net/liuhe688/article/details/6715983/和http://blog.chinaunix.net/uid-22816738-id-3802353.html

B、关于多线程对db的使用，正确的方法可以参考:http://blog.csdn.net/sky_monkey/article/details/23820021

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