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问oracle中的Base64编码与解码
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Stack Overflow用户

提问于 2010-09-27 21:34:33

回答 4查看 162.5K关注 0票数 44

如何在Oracle中对值进行Base64编码/解码？

oracle

base64

回答 4

Stack Overflow用户

回答已采纳

发布于 2010-09-28 01:27:16

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

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;

试试看。

更新：经过一个小的调整后，我想出了这个，所以现在它是双向工作的：

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;

你可以查看它：

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，这是我刚刚想出来的适用于CLOB的转换示例。试着为你的乳房解决这个问题。:)

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;

票数 58

Stack Overflow用户

发布于 2016-11-29 03:37:38

使用utl_encode.base64_encode和utl_encode.base64_decode解决方案有一个限制，它们只能处理最多32,767个字符/字节的字符串。

如果你不得不转换更大的字符串，你将面临几个障碍。

BASE64_ENCODE该函数必须读取3个字节并对其进行转换。在多字节字符的情况下(例如，以UTF-8存储的öäüè€，也称为AL32UTF8)，3字符不一定也是3字节。为了始终读取3个字节，你必须首先将你的CLOB转换成BLOB。
同样的问题也适用于BASE64_DECODE。该函数必须读取4个字节并将其转换为3个字节。这3个字节不一定也是3个，base64-- NEW_LINE (CR和/或LF)字符，每个64个字符。这样的换行符在解码时必须忽略。

考虑到所有这些，全功能的解决方案可能是这样的：

CREATE OR REPLACE FUNCTION DecodeBASE64(InBase64Char IN OUT NOCOPY CLOB) RETURN CLOB IS

    blob_loc BLOB;
    clob_trim CLOB;
    res CLOB;

    lang_context INTEGER := DBMS_LOB.DEFAULT_LANG_CTX;
    dest_offset INTEGER := 1;
    src_offset INTEGER := 1;
    read_offset INTEGER := 1;
    warning INTEGER;
    ClobLen INTEGER := DBMS_LOB.GETLENGTH(InBase64Char);

    amount INTEGER := 1440; -- must be a whole multiple of 4
    buffer RAW(1440);
    stringBuffer VARCHAR2(1440);
    -- BASE64 characters are always simple ASCII. Thus you get never any Mulit-Byte character and having the same size as 'amount' is sufficient

BEGIN

    IF InBase64Char IS NULL OR NVL(ClobLen, 0) = 0 THEN 
        RETURN NULL;
    ELSIF ClobLen<= 32000 THEN
        RETURN UTL_RAW.CAST_TO_VARCHAR2(UTL_ENCODE.BASE64_DECODE(UTL_RAW.CAST_TO_RAW(InBase64Char)));
    END IF;        
    -- UTL_ENCODE.BASE64_DECODE is limited to 32k, process in chunks if bigger    

    -- Remove all NEW_LINE from base64 string
    ClobLen := DBMS_LOB.GETLENGTH(InBase64Char);
    DBMS_LOB.CREATETEMPORARY(clob_trim, TRUE);
    LOOP
        EXIT WHEN read_offset > ClobLen;
        stringBuffer := REPLACE(REPLACE(DBMS_LOB.SUBSTR(InBase64Char, amount, read_offset), CHR(13), NULL), CHR(10), NULL);
        DBMS_LOB.WRITEAPPEND(clob_trim, LENGTH(stringBuffer), stringBuffer);
        read_offset := read_offset + amount;
    END LOOP;

    read_offset := 1;
    ClobLen := DBMS_LOB.GETLENGTH(clob_trim);
    DBMS_LOB.CREATETEMPORARY(blob_loc, TRUE);
    LOOP
        EXIT WHEN read_offset > ClobLen;
        buffer := UTL_ENCODE.BASE64_DECODE(UTL_RAW.CAST_TO_RAW(DBMS_LOB.SUBSTR(clob_trim, amount, read_offset)));
        DBMS_LOB.WRITEAPPEND(blob_loc, DBMS_LOB.GETLENGTH(buffer), buffer);
        read_offset := read_offset + amount;
    END LOOP;

    DBMS_LOB.CREATETEMPORARY(res, TRUE);
    DBMS_LOB.CONVERTTOCLOB(res, blob_loc, DBMS_LOB.LOBMAXSIZE, dest_offset, src_offset,  DBMS_LOB.DEFAULT_CSID, lang_context, warning);

    DBMS_LOB.FREETEMPORARY(blob_loc);
    DBMS_LOB.FREETEMPORARY(clob_trim);
    RETURN res;    

END DecodeBASE64;




CREATE OR REPLACE FUNCTION EncodeBASE64(InClearChar IN OUT NOCOPY CLOB) RETURN CLOB IS

    dest_lob BLOB;  
    lang_context INTEGER := DBMS_LOB.DEFAULT_LANG_CTX;
    dest_offset INTEGER := 1;
    src_offset INTEGER := 1;
    read_offset INTEGER := 1;
    warning INTEGER;
    ClobLen INTEGER := DBMS_LOB.GETLENGTH(InClearChar);

    amount INTEGER := 1440; -- must be a whole multiple of 3
    -- size of a whole multiple of 48 is beneficial to get NEW_LINE after each 64 characters 
    buffer RAW(1440);
    res CLOB := EMPTY_CLOB();

BEGIN

    IF InClearChar IS NULL OR NVL(ClobLen, 0) = 0 THEN 
        RETURN NULL;
    ELSIF ClobLen <= 24000 THEN
        RETURN UTL_RAW.CAST_TO_VARCHAR2(UTL_ENCODE.BASE64_ENCODE(UTL_RAW.CAST_TO_RAW(InClearChar)));
    END IF;
    -- UTL_ENCODE.BASE64_ENCODE is limited to 32k/(3/4), process in chunks if bigger    

    DBMS_LOB.CREATETEMPORARY(dest_lob, TRUE);
    DBMS_LOB.CONVERTTOBLOB(dest_lob, InClearChar, DBMS_LOB.LOBMAXSIZE, dest_offset, src_offset, DBMS_LOB.DEFAULT_CSID, lang_context, warning);
    LOOP
        EXIT WHEN read_offset >= dest_offset;
        DBMS_LOB.READ(dest_lob, amount, read_offset, buffer);
        res := res || UTL_RAW.CAST_TO_VARCHAR2(UTL_ENCODE.BASE64_ENCODE(buffer));       
        read_offset := read_offset + amount;
    END LOOP;
    DBMS_LOB.FREETEMPORARY(dest_lob);
    RETURN res;

END EncodeBASE64;

票数 12

Stack Overflow用户

发布于 2013-11-13 02:28:40

所有之前的帖子都是正确的。剥猫皮的方法不止一种。下面是做同样事情的另一种方法：(只需将"what_ever_you_want_to_convert“替换为您的字符串并在Oracle中运行它：

    set serveroutput on;
    DECLARE
    v_str VARCHAR2(1000);
    BEGIN
    --Create encoded value
    v_str := utl_encode.text_encode
    ('what_ever_you_want_to_convert','WE8ISO8859P1', UTL_ENCODE.BASE64);
    dbms_output.put_line(v_str);
    --Decode the value..
    v_str := utl_encode.text_decode
    (v_str,'WE8ISO8859P1', UTL_ENCODE.BASE64);
    dbms_output.put_line(v_str);
    END;
    /

source

票数 2

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/3804279

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