Java FX 图像显示在搜索查询中

Question

我最近在使用 blob 图像上传图像并且它有效但是现在当我尝试在搜索中搜索特定的人时，它没有出现我试图将 blob 图像转换为字节并以 java fx 形式

显示在图像字段中

这是我的代码

 @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) {

            }
        }

    }

这是我的文件上传代码，有效

文件上传

 @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");

        }

    }

验证我尝试了我的第一个字段，该字段正在从数据库中读取结果为“2”的测试数据但员工“2”的图像未加载并崩溃

任何帮助将不胜感激谢谢

错误

Answer 1

ResultSet 中的游标（指向当前行的指针）最初指向在第一行之前。 next() 方法 returns 一个布尔值，指示是否有更多行要移动到，如果有则移动到下一行。

在您发布的代码中，您从不调用 rs.next()，因此当您尝试检索 ID 和图像时，光标未指向任何行，并且（我认为）抛出异常.

在您的情况下，由于您正在搜索似乎是主键的内容，因此您期望返回零行或一行。所以你需要：

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) {

        }
    }

}

Java FX 图像显示在搜索查询中

Java FX image display on search query

java

blob

javafx