java - 读取 Blob 文件而不将其保存为文件

Question

我计划使用公钥加密字符串，该公钥作为 Blob 存储在数据库中。我创建了名为 readBlob() 的方法来读取 key 并将其保存到文件中。

  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);
            }        
        }
  }

它工作得很好，但我不需要将其保存到本地文件，我需要一种方法来读取 Blob 而不保存它。

Answer 1

您可以使用getBlob

Blob key = result.getBlob("key")

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