如何在 Sqlite & 中将图像存储为 blob如何找回它？

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);
}

用于检索图像：

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 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;
}

要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();
}

为了检索图像，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;
    }
}

最后将此图像加载到图像视图中

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

Answer 2

在 DBAdaper 即数据库帮助程序类中声明这样的表

 private static final String USERDETAILS=
    "create table userdetails(usersno integer primary key autoincrement,userid text not null ,username text not null,password text not null,photo BLOB,visibility text not null);";

插入这样的值，

图像转换为 byte[]

ByteArrayOutputStream baos = new ByteArrayOutputStream();  
Bitmap bitmap = ((BitmapDrawable)getResources().getDrawable(R.drawable.common)).getBitmap();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);   
byte[] photo = baos.toByteArray(); 
db.insertUserDetails(value1,value2, value3, photo,value2);

首先在 DEAdaper 类中将

 public long insertUserDetails(String uname,String userid, String pass, byte[] photo,String visibility) 
{
    ContentValues initialValues = new ContentValues();
    initialValues.put("username", uname);
    initialValues.put("userid",userid);
    initialValues.put("password", pass);
    initialValues.put("photo",photo);
    initialValues.put("visibility",visibility);
    return db.insert("userdetails", null, initialValues);
}

检索图像如下

Cursor cur=your query;
while(cur.moveToNext())
{
     byte[] photo=cur.getBlob(index of blob cloumn);
}

将 byte[] 转换为图像

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

我认为此内容可以解决您的问题

Answer 3

在 insert()

public void insert(String tableImg, Object object,
        ContentValues dataToInsert) {

   db.insert(tablename, null, dataToInsert);
}

希望它能帮助你。

Answer 4

对于一个ionic项目

    var imgURI       = "";
    var imgBBDD      = ""; //sqllite for save into

    function takepicture() {
                var options = {
                    quality : 75,
                    destinationType : Camera.DestinationType.DATA_URL,
                    sourceType : Camera.PictureSourceType.CAMERA,
                    allowEdit : true,
                    encodingType: Camera.EncodingType.JPEG,
                    targetWidth: 300,
                    targetHeight: 300,
                    popoverOptions: CameraPopoverOptions,
                    saveToPhotoAlbum: false
                };

                $cordovaCamera.getPicture(options).then(function(imageData) {
                    imgURI = "data:image/jpeg;base64," + imageData;
                    imgBBDD = imageData;
                }, function(err) {
                    // An error occured. Show a message to the user
                });
            }

现在我们将imgBBDD放入SqlLite

     function saveImage = function (theId, theimage){
      var insertQuery = "INSERT INTO images(id, image) VALUES("+theId+", '"+theimage+"');"
      console.log('>>>>>>>');
      DDBB.SelectQuery(insertQuery)
                    .then( function(result) {
                        console.log("Image saved");
                    })
                    .catch( function(err) 
                     {
                        deferred.resolve(err);
                        return cb(err);
                    });
    }

A服务器端（php）

        $request = file_get_contents("php://input"); // gets the raw data
        $dades = json_decode($request,true); // true for return as array


    if($dades==""){
            $array = array();
            $array['error'] = -1;
            $array['descError'] = "Error when get the file";
            $array['logError'] = '';
            echo json_encode($array);
            exit;
        }
        //send the image again to the client
        header('Content-Type: image/jpeg');
        echo '';

Answer 5

byte[] byteArray = rs.getBytes("columnname");  

Bitmap bm = BitmapFactory.decodeByteArray(byteArray, 0 ,byteArray.length);

Answer 6

您可能还想对 Base64 进行编码和解码

    function uncompress(str:String):ByteArray {
            import mx.utils.Base64Decoder;
            var dec:Base64Decoder = new Base64Decoder();
            dec.decode(str);
            var newByteArr:ByteArray=dec.toByteArray();        
            return newByteArr;
        }


    // Compress a ByteArray into a Base64 String.
    function compress(bytes:ByteArray):String { 
        import mx.utils.Base64Decoder; //Transform String in a ByteArray.
        import mx.utils.Base64Encoder; //Transform ByteArray in a readable string.
        var enc:Base64Encoder = new Base64Encoder();    
        enc.encodeBytes(bytes);
        return enc.drain().split("\n").join("");
    }