所以，您似乎遇到了一系列复杂的问题。让我们从这里开始，从数据库中加载数据...
while(rs.next())
{
row = new Vector(columnsNumber);
for(int i=1; i<=columnsNumber; i++)
{
// adding the rows in "row vector"
InputStream binaryStream = rs.getBinaryStream(i);
row.add(rs.getString(i));
row.add(rs.getBinaryStream(8));
}
// adding the rows in the database
rowdata.add(row);
}
因此，对于ResultSet 中的每一行，您可以查看列，但是对于每一列，您添加 String 值和最后一列中的 blob，因此 blob 将被添加 6 次（基于在您的屏幕截图上）。显然，这不是您想要的，也是您在其他每一列中获得java.io.ByteArrayInputStream@1cb63183 的原因。
相反，您想遍历列1-columnsNumbers - 1，因为我们不想要最后一列，并将图像添加到最后一列，可能类似于...
while(rs.next())
{
row = new Vector(columnsNumber);
for(int i=1; i < columnsNumber; i++)
{
// adding the rows in "row vector"
InputStream binaryStream = rs.getBinaryStream(i);
row.add(rs.getString(i));
}
row.add(rs.getBinaryStream(8));
// adding the rows in the database
rowdata.add(row);
}
下一个问题...
它仍然在最后一列打印java.io.ByteArrayInputStream@1cb63183！？
这仅仅是因为您添加到row Vector 的只是表示数据库中二进制数据的二进制流，JTable 无法渲染它。您应该首先查看Concepts: Editors and Renderers 和Using Custom Renderers，了解有关如何自定义这些组件的渲染的更多详细信息
首先，我们需要将二进制数据转换为我们可以使用的图像格式
row.add(ImageIO.read(rs.getBinaryStream(8)));
并使用类似于Rendering BufferedImage in JTable cell 中概述的内容
或
row.add(new ImageIcon(ImageIO.read(rs.getBinaryStream(8))));
这应该允许“默认”TableCellRenderer 呈现它
可运行示例...
警告： 这个例子有点长，因为我必须构建数据库并填充它。为简单起见，它使用独立的H2 Database engine，但应该可以转换为大多数其他数据库。该示例还使用了blob 的列类型，这是故意的，因为它提高了数据库引擎的性能。
使用DefaultTableModel 时在JTable 中显示图像的问题是，DefaultTableModel 从TableModel#getColumnClass 方法返回Object.class
即使DefaultTableModel 文档也注意到了这一点...
警告： DefaultTableModel 返回一个
Object 的列类。什么时候
DefaultTableModel 与
TableRowSorter 这将导致广泛使用
toString，用于非String 数据类型
太贵了。如果您使用 DefaultTableModel 和
TableRowSorter 强烈建议您覆盖
getColumnClass 返回适当的类型。
我通过自定义从TestPane#makeTableModel 返回的DefaultTableModel 克服了这个问题...
DefaultTableModel model = new DefaultTableModel(new String[]{"Name", "Image"}, 0) {
@Override
public Class<?> getColumnClass(int columnIndex) {
return columnIndex == 1 ? Icon.class : super.getColumnClass(columnIndex);
}
};
这允许JTable 使用正确的TableCellRenderer
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.imageio.ImageIO;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;
public class Main {
public static void main(String[] args) {
try {
Class.forName("org.h2.Driver");
makeDatabase();
populateDatabase();
new Main();
} catch (ClassNotFoundException | SQLException | IOException exp) {
exp.printStackTrace();
}
}
protected static Connection makeConnection() throws SQLException {
String path = "jdbc:h2:./TestDatabase";
return DriverManager.getConnection(path, "sa", "");
}
protected static void makeDatabase() throws SQLException {
String cmd = "create table if not exists fruits ("
+ "key BIGINT IDENTITY, "
+ "name varchar(128), "
+ "image longblob)";
try (Connection con = makeConnection()) {
try (PreparedStatement stmt = con.prepareStatement(cmd)) {
System.out.println("> Make fruits table");
stmt.executeUpdate();
}
}
}
protected static void populateDatabase() throws SQLException, IOException {
removeAlFruits();
insert("Apple", ImageIO.read(new File("Apple.png")));
insert("Banana", ImageIO.read(new File("Banana.png")));
insert("Cherries", ImageIO.read(new File("Cherries.png")));
insert("Grapes", ImageIO.read(new File("Grapes.png")));
insert("Orange", ImageIO.read(new File("Orange.png")));
insert("Pear", ImageIO.read(new File("Pear.png")));
insert("Pine Apple", ImageIO.read(new File("PineApple.png")));
insert("Strewberry", ImageIO.read(new File("Strewberry.png")));
insert("Water Melon", ImageIO.read(new File("WaterMelon.png")));
}
protected static void insert(String name, BufferedImage image) throws SQLException, IOException {
String cmd = "insert into fruits (name, image) values (?, ?)";
try (Connection con = makeConnection()) {
try (PreparedStatement stmt = con.prepareStatement(cmd)) {
try (InputStream is = convertImageToInputStream(image)) {
System.out.println("> Insert " + name);
stmt.setString(1, name);
stmt.setBinaryStream(2, is);
int rows = stmt.executeUpdate();
System.out.println("> " + rows + " rows updated");
}
}
}
}
protected static InputStream convertImageToInputStream(BufferedImage image) throws IOException {
ByteArrayOutputStream baos = null;
ByteArrayInputStream bais = null;
try {
baos = new ByteArrayOutputStream();
ImageIO.write(image, "png", baos);
baos.close();
bais = new ByteArrayInputStream(baos.toByteArray());
} finally {
if (baos != null) {
try {
baos.close();
} catch (IOException ex) {
}
}
}
return bais;
}
protected static void removeAlFruits() throws SQLException {
String cmd = "delete from fruits";
try (Connection con = makeConnection()) {
try (PreparedStatement stmt = con.prepareStatement(cmd)) {
System.out.println("> Remove all fruits");
int rows = stmt.executeUpdate();
System.out.println("> " + rows + " rows updated");
}
}
}
public Main() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (SQLException | IOException ex) {
ex.printStackTrace();
}
}
});
}
public class TestPane extends JPanel {
public TestPane() throws SQLException, IOException {
setLayout(new BorderLayout());
DefaultTableModel model = makeTableModel();
JTable table = new JTable(model);
table.setRowHeight(100);
add(new JScrollPane(table));
}
protected DefaultTableModel makeTableModel() throws SQLException, IOException {
DefaultTableModel model = new DefaultTableModel(new String[]{"Name", "Image"}, 0) {
@Override
public Class<?> getColumnClass(int columnIndex) {
return columnIndex == 1 ? Icon.class : super.getColumnClass(columnIndex);
}
};
String cmd = "select name, image from fruits";
try (Connection con = makeConnection()) {
try (PreparedStatement stmt = con.prepareStatement(cmd)) {
try (ResultSet rs = stmt.executeQuery()) {
while (rs.next()) {
String name = rs.getString(1);
Blob blob = rs.getBlob(2);
ImageIcon icon = null;
try (InputStream is = blob.getBinaryStream()) {
BufferedImage img = ImageIO.read(is);
icon = new ImageIcon(img);
}
model.addRow(new Object[]{name, icon});
}
}
}
}
return model;
}
}
}
替代方法是使用自定义TableCellRender，如Rendering BufferedImage in JTable cell 中所示