android - 如何将图像存储为 Sqlite 中的 blob 以及如何检索它？

Question

我想将图像(来自 url)存储到 sqlite 数据库中。

为此我使用:

db = new DataBase(getApplicationContext());
URL url = new URL("http://sree.cc/wp-content/uploads/schogini_team.png");
URLConnection ucon = url.openConnection();
InputStream is = ucon.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is,128);
ByteArrayBuffer barb= new ByteArrayBuffer(128);

int current = 0;
while ((current = bis.read()) != -1) {
    barb.append((byte) current);
}

ContentValues filedata= new ContentValues();

filedata.put(DataBase.IMG_SRC,barb.toByteArray());

db.insert(DataBase.Table_Img, null, filedata);

在Insert()中:

public void insert(String tableImg, Object object,
        ContentValues dataToInsert) {
    // TODO Auto-generated method stub
    String sql = "INSERT INTO "+tableImg+" ("+ID+","+IMG_SRC+") " +
            "VALUES ('"+1+"','"+dataToInsert+"')";
    db.execSQL(sql);
}

对于图像的检索:

Cursor cursor = db.selectDataToShow(DataBase.Table_Img, DataBase.IMG_SRC);

byte[] imageByteArray=cursor.getBlob(cursor.getColumnIndex(DataBase.IMG_SRC));      
cursor.close();

ByteArrayInputStream imageStream = new ByteArrayInputStream(imageByteArray);
Bitmap theImage = BitmapFactory.decodeStream(imageStream);

System.out.println(">>>>>>>>>>>>>>>>>>>>>> "+theImage);

所以这里我得到了 null。

在我的数据库中，图像的值存储为:Image=[B@43e5ac48]

Answer 1

这是我用于我的应用程序的代码

此代码将从 url 获取图像并将其转换为字节数组

byte[] logoImage = getLogoImage(IMAGEURL);

private byte[] getLogoImage(String url){
     try {
             URL imageUrl = new URL(url);
             URLConnection ucon = imageUrl.openConnection();

             InputStream is = ucon.getInputStream();
             BufferedInputStream bis = new BufferedInputStream(is);

             ByteArrayBuffer baf = new ByteArrayBuffer(500);
             int current = 0;
             while ((current = bis.read()) != -1) {
                  baf.append((byte) current);
             }

             return baf.toByteArray();
     } catch (Exception e) {
          Log.d("ImageManager", "Error: " + e.toString());
     }
     return null;
}

为了将图像保存到数据库，我使用了此代码。

 public void insertUser(){
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        String delSql = "DELETE FROM ACCOUNTS";
        SQLiteStatement delStmt = db.compileStatement(delSql);
        delStmt.execute();

        String sql = "INSERT INTO ACCOUNTS (account_id,account_name,account_image) VALUES(?,?,?)";
        SQLiteStatement insertStmt = db.compileStatement(sql);
        insertStmt.clearBindings();
        insertStmt.bindString(1, Integer.toString(this.accId));
        insertStmt.bindString(2,this.accName);
        insertStmt.bindBlob(3, this.accImage);
        insertStmt.executeInsert();
        db.close();
}

要检索图像，这是我使用的代码。

public Account getCurrentAccount() {
    SQLiteDatabase db = dbHelper.getWritableDatabase();
    String sql = "SELECT * FROM ACCOUNTS";
    Cursor cursor = db.rawQuery(sql, new String[] {});

    if(cursor.moveToFirst()){
        this.accId  = cursor.getInt(0);
        this.accName = cursor.getString(1);
        this.accImage = cursor.getBlob(2);
    }
    if (cursor != null && !cursor.isClosed()) {
        cursor.close();
    }
    db.close();
    if(cursor.getCount() == 0){
        return null;
    } else {
        return this;
    }
}

最后把这张图片加载到一个imageview中

logoImage.setImageBitmap(BitmapFactory.decodeByteArray( currentAccount.accImage, 
        0,currentAccount.accImage.length));