Java FX 图像显示在搜索查询上

Question

i was recently working on image upload using blob images and it works but now when i try to search for the specific person in the search it is not showing up i was trying to convert blob image to byte and display in image field in java fx form

this is my code

 @FXML
    private void handleSearchResults(KeyEvent event) throws IOException {

        try {

            String sql = "select * from Staff_information where id=? ";
            pst = conn.prepareStatement(sql);
            pst.setString(1, txtSearch.getText());
            rs = pst.executeQuery();

            String add1 = rs.getString("id");
            txtid.setText(add1);

            byte[] img = rs.getBytes("Image");
            BufferedImage bufferedImage = ImageIO.read(img);
            WritableImage image = SwingFXUtils.toFXImage(bufferedImage, null);

            imageDisplay.setImage(image);
            imageDisplay.setFitWidth(200);
            imageDisplay.setFitHeight(200);


        } catch (Exception e) {
            System.out.println("missingdata");
        } finally {

            try {

                rs.close();
                pst.close();

            } catch (Exception e) {

            }
        }

    }

This is my code for file upload which works

File Upload

 @FXML
    private void UploadImageActionPerformed(ActionEvent event) {

        FileChooser fileChooser = new FileChooser();

        //Set extension filter
        FileChooser.ExtensionFilter extFilterJPG
                = new FileChooser.ExtensionFilter("JPG files (*.JPG)", "*.JPG");
        FileChooser.ExtensionFilter extFilterjpg
                = new FileChooser.ExtensionFilter("jpg files (*.jpg)", "*.jpg");
        FileChooser.ExtensionFilter extFilterPNG
                = new FileChooser.ExtensionFilter("PNG files (*.PNG)", "*.PNG");
        FileChooser.ExtensionFilter extFilterpng
                = new FileChooser.ExtensionFilter("png files (*.png)", "*.png");
        fileChooser.getExtensionFilters()
                .addAll(extFilterJPG, extFilterjpg, extFilterPNG, extFilterpng);
        //Show open file dialog
        File file = fileChooser.showOpenDialog(null);

        try {
            BufferedImage bufferedImage = ImageIO.read(file);
            WritableImage image = SwingFXUtils.toFXImage(bufferedImage, null);
            img.setImage(image);
            img.setFitWidth(200);
            img.setFitHeight(200);
            img.scaleXProperty();
            img.scaleYProperty();
            img.setSmooth(true);
            img.setCache(true);
            FileInputStream fin = new FileInputStream(file);
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            byte[] buf = new byte[1024];

            for (int readNum; (readNum = fin.read(buf)) != -1;) {
                bos.write(buf, 0, readNum);
            }
            person_image = bos.toByteArray();

        } catch (IOException ex) {
            Logger.getLogger("ss");
        }
    }

byte[] person_image = null;

 @FXML
    private void handleaddemployee(ActionEvent event) throws IOException {

        try {
                String empID = "nill";
                if (!txtempID.getText().equals("")) {
                    empID = txtempID.getText();
                }

                Employee e = new Employee(
                        empID,
                        person_image 
                );
                dbemployee.addEmployee(e);

            } else {
                 System.out.println("not working");
            }

        } catch (SQLException ex) {
           System.out.println("error");

        } catch (NumberFormatException e) {
         System.out.println("number error");

        }

    }

to verify i tried my first field that is reading from database which gives a result "2" test data but image for the employee "2" is not loading and crashing

any help will be appreciated thank you

Error

Error

Answer 1

The cursor (pointer to the current row) in a ResultSet initially points before the first row. The next() method returns a boolean indicating if there are more rows to move to, and moves to the next row if there is one.

In the code you posted, you never call rs.next() , so when you try to retrieve the id and the image, the cursor is not pointing to any row, and (I think) an exception is thrown.

In your case, since you're searching by what appears to be a primary key, you are expecting zero or one rows to be returned. So you need:

private void handleSearchResults(KeyEvent event) throws IOException {

    try {

        String sql = "select * from Staff_information where id=? ";
        pst = conn.prepareStatement(sql);
        pst.setString(1, txtSearch.getText());
        rs = pst.executeQuery();

        if (rs.next()) {
            String add1 = rs.getString("id");
            txtid.setText(add1);

            byte[] img = rs.getBytes("Image");
            BufferedImage bufferedImage = ImageIO.read(img);
            WritableImage image = SwingFXUtils.toFXImage(bufferedImage, null);

            imageDisplay.setImage(image);
            imageDisplay.setFitWidth(200);
            imageDisplay.setFitHeight(200);
        } else {
            // no match found.... inform user, etc
        }

    } catch (Exception e) {
        System.out.println("missingdata");
    } finally {

        try {

            rs.close();
            pst.close();

        } catch (Exception e) {

        }
    }

}