java - JAVAFX：从数据库加载图像

Question

我需要一些关于从数据库加载图像的帮助。如何从数据库中检索图像并将其放入 Image/ImageView？

非常感谢！

Answer 1

import java.nio.ByteBuffer;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.effect.DropShadow;
import javafx.scene.image.PixelFormat;
import javafx.scene.image.PixelWriter;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class ImageOpsTest extends Application {

    // Image Data
    private static final int IMAGE_WIDTH = 10;
    private static final int IMAGE_HEIGHT = 10;
    private byte imageData[] = 
        new byte[IMAGE_WIDTH * IMAGE_HEIGHT * 3];

    // Drawing Surface (Canvas)
    private GraphicsContext gc;
    private Canvas canvas;
    private Group root;

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("PixelWriter Test");
        root = new Group();
        canvas = new Canvas(200, 200);
        canvas.setTranslateX(100);
        canvas.setTranslateY(100);
        gc = canvas.getGraphicsContext2D();
        createImageData();
        drawImageData();
        primaryStage.setScene(new Scene(root, 400, 400));
        primaryStage.show();

    }

    private void createImageData() {
        int i = 0;
        for (int y = 0; y < IMAGE_HEIGHT; y++) {
            int r = y * 255 / IMAGE_HEIGHT;
            for (int x = 0; x < IMAGE_WIDTH; x++) {
                int g = x * 255 / IMAGE_WIDTH;
                imageData[i] = (byte) r;
                imageData[i + 1] = (byte) g;
                i += 3;
            }
        }
    }

    private void drawImageData() {
        boolean on = true;
        PixelWriter pixelWriter = gc.getPixelWriter();
        PixelFormat<ByteBuffer> pixelFormat = PixelFormat.getByteRgbInstance();
        for (int y = 50; y < 150; y += IMAGE_HEIGHT) {
            for (int x = 50; x < 150; x += IMAGE_WIDTH) {
                if (on) {
                    pixelWriter.setPixels(x, y, IMAGE_WIDTH,
                            IMAGE_HEIGHT, pixelFormat, imageData, 
                            0, IMAGE_WIDTH * 3);
                }
                on = !on;
            }
            on = !on;
        }

        // Add drop shadow effect
        gc.applyEffect(new DropShadow(20, 20, 20, Color.GRAY));
        root.getChildren().add(canvas);
    }
}  

This example taken from the docs demonstrates how you can create an image out of byte[]. When you store image into the database, you get them back as byte[].
Now, how you retrieve the image from the database is completely up to you but once you retrieve it, you can use the program above to convert it into an image.