【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p3、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;

 

<span styl

【转】android三个特殊的资源目录 /res/xm ... | 【转】绝对有用，Android系统更改事件之横 ...

• 2011-05-17 14:09
• 浏览 6535
• 评论(0)
• 分类:非技术
• 查看更多