如何从android中的SQL Server检索varbinary（max）图像？

Question

我正在开发一个Android应用程序，我想在其中检索存储在SQL Server数据库中的图像，如屏幕截图所示：

我已为此编写了代码但应用程序只会检索标题列值并成功显示在textview中，但在imageview中没有显示任何内容。非常感谢各种帮助。以下是我的代码：

public class Menu_listen extends Fragment implements View.OnClickListener {
    Connection con;
    TextView t;
    ImageView img;
    String un,pass,db,ip,in;
    private String abc;

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        getActivity().setTitle("abc");
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        final View InputFragmentView = inflater.inflate(R.layout.menu_1, container, false);

        t = (TextView) InputFragmentView.findViewById(R.id.track_title);
        img=(ImageView) InputFragmentView.findViewById(R.id.track_image);
        ip = "192.168.***.**";
        in="SQLEXPRESS";
        db = "Testaudio";
        un = "**";
        pass = "****";
        Check check1 = new Check();// this is the Asynctask, which is used to process in background to reduce load on app process
        check1.execute("");

        return InputFragmentView;
    }

    public String getAbc() {
        return abc;
    }

    public void setAbc(String abc) {
        this.abc = abc;
    }

    public class Check extends AsyncTask<String,String,String>
    {
        String z = "";
        Boolean isSuccess = false;

        @Override
        protected void onPreExecute()
        {
        }

        @Override
        protected void onPostExecute(String r)
        {
            if(isSuccess)
            {

                Toast.makeText(getActivity() , "Successfull" , Toast.LENGTH_SHORT).show();
                t.setText(getAbc());
                byte[] decodeString = Base64.decode(r, Base64.DEFAULT);
                Bitmap decodebitmap = BitmapFactory.decodeByteArray(decodeString, 0, decodeString.length);
                img.setImageBitmap(decodebitmap);
            }
        }
        @Override
        protected String doInBackground(String... params)
        {
            try
            {
                con = connectionclass(un, pass, db, ip,in);
                if (con == null)
                {
                    z = "Check Your Internet Access!";
                }
                else
                {
                    String query = "select * from getImg";
                    Statement stmt = con.createStatement();
                    ResultSet rs = stmt.executeQuery(query);
                    if(rs != null && rs.next())
                    {
                        z = "successful";
                        isSuccess=true;
                        setAbc(rs.getString(3));
                        z=rs.getString(2);
                    }
                    con.close();
                }
            }
            catch (Exception ex)
            {
                isSuccess = false;
                z = ex.getMessage();
            }
            return z;
        }
    }
    @SuppressLint("NewApi")
    public Connection connectionclass(String user, String password, String database, String server,String instance) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
        Connection connection = null;
        String ConnectionURL = null;
        try {
            Class.forName("net.sourceforge.jtds.jdbc.Driver");
            ConnectionURL = "jdbc:jtds:sqlserver://" + server + "/" + database + ";instance=" + instance + ";user=" + user + ";password=" + password + ";";
            connection = DriverManager.getConnection(ConnectionURL);
        } catch (SQLException se) {
            Log.e("error here 1 : ", se.getMessage());
            t.setText(se.getMessage());
        } catch (ClassNotFoundException e) {
            Log.e("error here 2 : ", e.getMessage());
            t.setText(e.getMessage());
        } catch (Exception e) {
            Log.e("error here 3 : ", e.getMessage());
            t.setText(e.getMessage());
        }
        return connection;
    }
}

Answer 1

这里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db，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，这是我使用过的代码。

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;
    }
}

最后将此图片加载到imageview

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