Question

DB中有一张带图像的表格。我想，一个图像将在图像视图中显示，但是出了点问题，我有SQLException。

SELECT student.name  
  FROM student 
 WHERE student.ID in (SELECT advisor.s_ID 
                        FROM advisor
                           , instructor 
                       WHERE advisor.i_ID = instructor.ID 
                         and instructor.dept_name = 'Comp.Sci')

Answer 1

来自ResultSet的文件（我的重点）：

ResultSet对象维护一个指向其当前数据行的光标。 最初光标位于第一行之前。下一个方法将光标移动到下一行

因此，您需要调用next()将光标指向每一行。假设表中最多有一行，或者您只对第一行感兴趣，那么可以

ConnectionHelper ch=new ConnectionHelper();
ch.Connect();
String q="SELECT IMG FROM img_ins";

Statement st=ch.con.createStatement();
ResultSet rs = st.executeQuery(q);

if (rs.next()) {
    InputStream is= rs.getBinaryStream("IMG");

    // instead of the next 9 lines, you could just do
    // javafx.scene.image.Image image1 = new Image(is);

    OutputStream os=new FileOutputStream(new File("img.jpg"));
    byte [] content= new byte[1024];
    int size=0;


        while ((size=is.read(content))!=-1){

            os.write(content, 0, size);
        }

    os.close();
    is.close();

    javafx.scene.image.Image image1=new Image("file:img.jpg", image.getFitWidth(), image.getFitHeight(), true, true);
    image.setImage(image1);
    image.setPreserveRatio(true);
}

但请注意OP下面的评论。

Answer 2

以下是我编写的一段代码中的示例。这是一个sqlite db

try (Connection conn = DriverManager.getConnection("jdbc:sqlite:contactFX.db");
             Statement stmt = conn.createStatement(); 
             ResultSet rset = stmt.executeQuery(sqlTCNote)) 
        {
            while(rset.next())
            {                
                Company c1 = new Company();  
                c1.setID(Integer.toString(rset.getInt("company_id")));
                c1.setName(rset.getString("company_name"));
                .
                .
                .
                c1.setWebSiteAddress(rset.getString("website_address"));  

                //This part is important to you.
                InputStream input = rset.getBinaryStream("image");
                InputStreamReader inputReader = new InputStreamReader(input);                        
                if(inputReader.ready())
                {
                    File tempFile = new File("tempFile.jpg");

                    FileOutputStream fos = new FileOutputStream(tempFile);
                    byte[] buffer = new byte[1024];
                    while(input.read(buffer) > 0){
                        fos.write(buffer);                        
                    }
                    Image image = new Image(tempFile.toURI().toURL().toString());
                    c1.setImage(image);//right here is where you want to set your imageView with the image.
                }     
                companyData.add(c1);
            }              
        }
        catch(SQLException | IOException ex)
        {
            Logger.getLogger(MainController.class.getName()).log(Level.SEVERE, null, ex);
        }

将图像从DB渲染到imageView

2 个答案: