oracle中的base64编解码 [英] Base64 encoding and decoding in oracle

问题描述

如何在 Oracle 中对值进行 Base64 编码/解码?

How can I do Base64 encode/decode a value in Oracle?

推荐答案

我已经实现了这一点，以通过我的 MS Exchange 服务器发送西里尔文电子邮件.

I've implemented this to send Cyrillic e-mails through my MS Exchange server.

function to_base64(t in varchar2) return varchar2 is
 begin
    return utl_raw.cast_to_varchar2(utl_encode.base64_encode(utl_raw.cast_to_raw(t)));
end to_base64;

试试吧.

upd:经过微小的调整后，我想出了这个，所以现在它可以双向工作了:

upd: after a minor adjustment I came up with this, so it works both ways now:

function from_base64(t in varchar2) return varchar2 is
begin
  return utl_raw.cast_to_varchar2(utl_encode.base64_decode(utl_raw.cast_to_raw(t)));
end from_base64;

你可以检查一下:

SQL> set serveroutput on
SQL> 
SQL> declare
  2    function to_base64(t in varchar2) return varchar2 is
  3    begin
  4      return utl_raw.cast_to_varchar2(utl_encode.base64_encode(utl_raw.cast_to_raw(t)));
  5    end to_base64;
  6  
  7    function from_base64(t in varchar2) return varchar2 is
  8    begin
  9      return utl_raw.cast_to_varchar2(utl_encode.base64_decode(utl_raw.cast_to_raw    (t)));
 10    end from_base64;
 11  
 12  begin
 13    dbms_output.put_line(from_base64(to_base64('asdf')));
 14  end;
 15  /

asdf

PL/SQL procedure successfully completed

upd2: 好的，这里有一个适用于 CLOB 的示例转换，我刚刚想出了.尝试为您的斑点解决这个问题.:)

upd2: Ok, here's a sample conversion that works for CLOB I just came up with. Try to work it out for your blobs. :)

declare

  clobOriginal     clob;
  clobInBase64     clob;
  substring        varchar2(2000);
  n                pls_integer := 0;
  substring_length pls_integer := 2000;

  function to_base64(t in varchar2) return varchar2 is
  begin
    return utl_raw.cast_to_varchar2(utl_encode.base64_encode(utl_raw.cast_to_raw(t)));
  end to_base64;

  function from_base64(t in varchar2) return varchar2 is
  begin
    return utl_raw.cast_to_varchar2(utl_encode.base64_decode(utl_raw.cast_to_raw(t)));
  end from_base64;

begin

  select clobField into clobOriginal from clobTable where id = 1;

  while true loop

    /*we substract pieces of substring_length*/
    substring := dbms_lob.substr(clobOriginal,
                                 least(substring_length, substring_length * n + 1 - length(clobOriginal)),
                                 substring_length * n + 1);  
    /*if no substring is found  - then we've reached the end of blob*/

    if substring is null then
      exit;
    end if;  

    /*convert them to base64 encoding and stack it in new clob vadriable*/
    clobInBase64 := clobInBase64 || to_base64(substring);          
    n := n + 1;  

  end loop;

  n := 0;
  clobOriginal := null;

  /*then we do the very same thing backwards - decode base64*/
  while true loop 

    substring := dbms_lob.substr(clobInBase64,
                                 least(substring_length, substring_length * n + 1 - length(clobInBase64)),
                                 substring_length * n + 1);  
    if substring is null then
      exit;
    end if;  
    clobOriginal := clobOriginal || from_base64(substring);  
    n := n + 1;  
  end loop; 

      /*and insert the data in our sample table - to ensure it's the same*/
  insert into clobTable (id, anotherClobField) values (1, clobOriginal);

end;

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