How do I read and insert BLOBs data from database?

最新推荐文章于 2025-12-01 18:34:47 发布

原创最新推荐文章于 2025-12-01 18:34:47 发布 · 130 阅读

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本文提供了一个Java程序示例，展示了如何使用JDBC插入和查询数据库中的BLOB类型数据，包括图片文件的读取与写入。

Only for reference.

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.sql.*;

public class TestOperBlob {
    private static String url = "jdbc:oracle:thin:@localhost:1521:orcl";
    private static String username = "test";
    private static String password = "test";
    
    public void queryBlob(){
      try{
          conn = getConnection();
          conn.setAutoCommit(false);

          String sql = "INSERT INTO pictures (name, description, image) VALUES (?, ?, ?)";
          PreparedStatement stmt = conn.prepareStatement(sql);
          stmt.setString(1, "java.gif");
          stmt.setString(2, "Java Official Logo");

          File image = new File("D:\\Projects\\kodejava\\web\\images\\java.gif");
          fis = new FileInputStream(image);
          stmt.setBinaryStream(3, fis, (int) image.length());
          stmt.execute();

          conn.commit();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeConnection(conn);
        }
    }

    public void insertBlob(){
      Connection conn = null;
      try {
            conn = getConnection();

            String sql = "SELECT name, description, image FROM pictures ";
            PreparedStatement stmt = conn.prepareStatement(sql);
            ResultSet resultSet = stmt.executeQuery();
            while (resultSet.next()) {
                String name = resultSet.getString(1);
                System.out.println("Name        = " + name);
                String description = resultSet.getString(2);
                System.out.println("Description = " + description);

                File image = new File("D:\\java.gif");
                FileOutputStream fos = new FileOutputStream(image);

                byte[] buffer = new byte[256];
                // Get the binary stream of our BLOB data
                InputStream is = resultSet.getBinaryStream(3);
                while (is.read(buffer) > 0) {
                    fos.write(buffer);
                }

                fos.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            if (fis != null) {
                fis.close();
            }
            closeConnection(conn);
        }
    }
    
    private static Connection getConnection() throws Exception {    
        Connection connection = null;    
        Class.forName("com.mysql.jdbc.Driver");    
        connection = DriverManager.getConnection(url, username, password);
        return connection;    
    }    
        
    private static void closeConnection(Connection connection) throws SQLException {    
        if (connection != null && !connection.isClosed()) {             
            connection.close();    
        }    
    }
    
    public static void main(String[] args) throws Exception {
        queryBlob();
        insertBlob();
    }
}