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.");