PostgreSQL java读取bytes字段

写入bytea：

　　　　　　  File img = new File("/tmp/eclipse.png");

            fin = new FileInputStream(img);

            con = DriverManager.getConnection(url, user, password);

            pst = con.prepareStatement("INSERT INTO images(data) VALUES(?)");

            pst.setBinaryStream(1, fin, (int) img.length());

            pst.executeUpdate();

            System.out.println("WriteImage.main() success.");
            

读取bytea：

　　　　　　  String query = "SELECT data, LENGTH(data) FROM images WHERE id = 1";

            pst = con.prepareStatement(query);

            ResultSet result = pst.executeQuery();

            result.next();  //offset to the first row

            fos = new FileOutputStream("//home//apple//Pictures//eclipse.png");

            int len = result.getInt(2);

            byte[] buf = result.getBytes("data");

            fos.write(buf, 0, len);

            System.out.println("read image.main() success.");