postgres jdbc 8.4 和 9 之间关于字节数组有什么变化？

发布于 2024-10-14 21:54:35 字数 1756 浏览 0 评论 0原文

我正在运行 Mac OSX 10.6 和 PostgreSQL 9.0。我编写了一个简单的 Java 应用程序，它将图像插入到 bytea 字段中，然后查询同一字段来检查它。

表格：

 CREATE TABLE test.test_table
   (
   id integer NOT NULL,
  image bytea,
  CONSTRAINT test_table_pkey PRIMARY KEY (id)
);

程序类似于：

//insert the file
    PreparedStatement ps = connection.prepareStatement("INSERT INTO test.test_table( id, image ) VALUES (?, ?);");
            byte[] bytesFromFile = readFile("img/test1.bmp");
            ps.setInt(1, 1);
            ps.setBytes(2, bytesFromFile);
            ps.execute();
            ps.close();

            PreparedStatement stmt = connection.prepareStatement("Select id,image from test.test_table");
            ResultSet rs = stmt.executeQuery();
    //Get the file from the BD  and save it to the FS 
            while (rs.next()) {
                String id = rs.getString(1);
                InputStream imageStream = rs.getBinaryStream(2);
                String imageName = OUTPUT_DIR + "/" + id + ".bmp";
                FileOutputStream f = new FileOutputStream(imageName);
                byte buff[] = new byte[1024];
                int l;
                while ((l = imageStream.read(buff)) > 0) {
                    f.write(buff, 0, l);
                }
                f.close();
                System.out.println("CREATED : " + imageName);// + " size " +

            }

以下是事实。

使用驱动程序 postgresql-9.0-801.jdbc4.jar 就可以了完美地工作在 PostgreSQL 8.4 和 PostgreSQL 9
使用驱动程序 8.4-701.jdbc4 有效仅在 PostgreSQL 8.4 中。
使用带有 PostgreSQL 的驱动程序 8.4-701.jdbc4 9 不行。提取的文件不同。 md5表明数据库中的内容与原始文件相同。因此，我的假设是问题出在提取文件期间。

我可以升级驱动程序，没问题。我关心的是：PostgreSQL 9 不再支持的通信协议内部发生了什么变化？

原文

I'm running Mac OSX 10.6 with PostgreSQL 9.0. I wrote a simple Java application that insert an image in a bytea field and then query the same field to check it.

The table:

 CREATE TABLE test.test_table
   (
   id integer NOT NULL,
  image bytea,
  CONSTRAINT test_table_pkey PRIMARY KEY (id)
);

The program is something like:

//insert the file
    PreparedStatement ps = connection.prepareStatement("INSERT INTO test.test_table( id, image ) VALUES (?, ?);");
            byte[] bytesFromFile = readFile("img/test1.bmp");
            ps.setInt(1, 1);
            ps.setBytes(2, bytesFromFile);
            ps.execute();
            ps.close();

            PreparedStatement stmt = connection.prepareStatement("Select id,image from test.test_table");
            ResultSet rs = stmt.executeQuery();
    //Get the file from the BD  and save it to the FS 
            while (rs.next()) {
                String id = rs.getString(1);
                InputStream imageStream = rs.getBinaryStream(2);
                String imageName = OUTPUT_DIR + "/" + id + ".bmp";
                FileOutputStream f = new FileOutputStream(imageName);
                byte buff[] = new byte[1024];
                int l;
                while ((l = imageStream.read(buff)) > 0) {
                    f.write(buff, 0, l);
                }
                f.close();
                System.out.println("CREATED : " + imageName);// + " size " +

            }

Here are the facts.

Using the driver
postgresql-9.0-801.jdbc4.jar it
works perfectly both in
PostgreSQL 8.4 and with PostgreSQL 9
Using the driver 8.4-701.jdbc4 works
only in PostgreSQL 8.4 .
Using the
driver 8.4-701.jdbc4 with PostgreSQL
9 doesn't work. The extracted file is different. An md5 shows that the content in the database is equals to the original file. Therefore, my assumption is that the problem is during the extraction of the file.

I can upgrade the driver, thats no problem. My concern is: what has changed inside the communication protocol that is no longer supported in PostgreSQL 9 ?

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