转:Android SQLite 数据库 存取 BLOB 二进制 文件
原文地址,转载请说明:http://blog.sina.com.cn/s/blog_539070ad0100nesa.html
Android开发时用到二进制数据(也可以理解为BYTE数组)的SQLite存取,可能会有人对存取如mp3、图片类文件困惑,其实mp3、图片类文件读到内存就可理解为BYTE数组,只要在下面的基础上增加将文件读到BYTE数组就可以了,其他操作是相同的(在网上搜了一段代码放下面了)。
写此文的目的是方便自己今后查询,当然碰巧方便了其他人就当我奉献了:)
package com.Jung.DH; import java.io.ByteArrayOutputStream; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.util.Log; // 数据操作类 public class testSeedDB { private Context mContext = null; private testDBHelper mDBHelper = null; private SQLiteDatabase mTestDatabase = null; private static final String DATABASE_NAME = "DHSeedData.db"; private static final int DATABASE_VERSION = 1; private static final String TABLE_SEED = "TBseed"; private static final String TABLE_INFO = "TBinfo"; // 构造函数,一个引用类的Context作为参数 public testSeedDB(Context context){ mContext = context; } // 打开数据库 public void open(){ mDBHelper = new testDBHelper(mContext,DATABASE_NAME, null, DATABASE_VERSION); mTestDatabase = mDBHelper.getWritableDatabase(); Log.i("testSeedDB", "open"); } // Close the database public void close(){ mDBHelper.close(); } public void CreateSeedTable() { // 创建数据表是先删除以前的,以免出错 String sql = "drop table "+ TABLE_SEED; try { mTestDatabase.execSQL(sql); } catch (SQLException e) { } // second create table sql = "CREATE TABLE IF NOT EXISTS " + TABLE_SEED + " (ID INTEGER PRIMARY KEY, ToyID INTEGER,ToySeed BLOB,ToyMemo TEXT);"; try { mTestDatabase.execSQL(sql); } catch (SQLException ex) { } Log.i("testSeedDB", "CreateSeedTable"); } public void CreateInfoTable() { // first delete old table String sql = "drop table"+ TABLE_INFO; try { mTestDatabase.execSQL(sql); } catch (SQLException e) { } // second create table sql = "CREATE TABLE IF NOT EXISTS " + TABLE_INFO + " (ToyID INTEGER PRIMARY KEY,ToySeed BLOB,ToyMemo TEXT not null);"; try { mTestDatabase.execSQL(sql); } catch (SQLException ex) { } } public void CleanSeedTable() { try { mTestDatabase.delete(TABLE_SEED, null, null); } catch (SQLException e) { } Log.i("testSeedDB", "ClearSeedTable"); } public void insertSeedItem(long ToyID, byte[]ToySeed) { String sqlstr = "insert into " + TABLE_SEED + " (ToyID, ToySeed,ToyMemo) values (?,?,?);"; Object[] args = new Object[]{ToyID,ToySeed,null}; try{ mTestDatabase.execSQL(sqlstr,args); } catch (SQLException ex) { } Log.i("testSeedDB", "insertSeedItem"); } public byte[] GetSeedItem(long ToyID) { Cursor cur; byte[] strSeed = null; String col[] = {"ToyID", "ToySeed" ,"ToyMemo"}; String strToy = "ToyID=" + new Integer((int) ToyID).toString(); try{ cur = mTestDatabase.query(TABLE_SEED, col, strToy, null, null, null, null); cur.moveToFirst(); strSeed = cur.getBlob(1); } catch (SQLException ex) { } if (cur !=null) cur.close; Log.i("testSeedDB", strToy); return strSeed; } // 数据操作的基础类,作为数据操作的内嵌子类 public class testDBHelper extends SQLiteOpenHelper { public testDBHelper(Context context, String name, CursorFactory factory, int version) { super(context, name, factory, version); // TODO Auto-generated constructor stub } @Override public voidonCreate(SQLiteDatabase db) { // TODO Auto-generated method stub } @Override public voidonUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub } } // end of testDBHelper }
// 读文件到 BYTE 来自网上未验证
//http://www.a3gs.com/BookViews.asp?InfoID=2865&ClassID=935
导入包:
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
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