在不保存文件的情况下读取Blob文件 [英] Read Blob file without saving it a file

问题描述

我计划使用作为Blob存储在数据库中的公共密钥对字符串进行加密.我创建了名为 readBlob()的方法来读取密钥并将其保存到文件中./p>

I have planned to encrypt a string using a public key which is stored in a database as Blob.I have created method called readBlob() to read the key and save it to the file.

  public static void readBlob(int userid, String filename) throws SQLException, IOException {
      String url = "jdbc:mysql://localhost:3306/bank";
        String user = "root";
        String password = "root";
        String email=null;

            Connection conn = DriverManager.getConnection(url, user, password);
            String sql = "select * from users where user_id=?";
            PreparedStatement statement = conn.prepareStatement(sql);
            statement.setLong(1, userid);
            ResultSet result = statement.executeQuery();
            File file = new File(filename);
            @SuppressWarnings("resource")
            FileOutputStream output = new FileOutputStream(file);
            String keys=null;

    while(result.next()) {
         byte[] buffer = new byte[1];
         InputStream input = result.getBinaryStream("key");
         while (input.read(buffer) > 0) {
             output.write(buffer);
            }        
        }
  }

它确实工作得很好，但是我不需要将其保存到本地文件中，我需要一种无需保存即可读取Blob的方法.

It worked really well but I don't need to save it to the local file ,I need a way to read the Blob without saving it.

推荐答案

您可以使用

以Java编程语言中Blob对象的形式检索此ResultSet对象的当前行中指定列的值.

Retrieves the value of the designated column in the current row of this ResultSet object as a Blob object in the Java programming language.

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