将Oracle 中的blob导出到文件中

declare

  l_directory varchar(200) := '__dir__';

    l_file UTL_FILE.FILE_TYPE; 

    l_buffer RAW(32767); 

    l_amount BINARY_INTEGER:=32767; 

    l_pos NUMBER:=1; 

    l_Blob Blob; 

    l_Blob_len Number; 

    l_lob_id number;

    CURSOR cur is

      select __id__ from __table_name__;

BEGIN 

  open cur;

    loop

      fetch cur into l_lob_id;

      EXIT when cur%NOTFOUND;

      select __blob_fild__ into l_Blob from __table_name__ where __id__=l_lob_id ;

      l_file:=UTL_FILE.FOPEN(l_directory,'adapter_blob.'||to_char(l_lob_id)||'.bin','wb',32767);

      l_Blob_len:=dbms_lob.getlength(l_Blob); 

      l_pos := 1;

      WHILE l_pos<l_Blob_len LOOP 

        DBMS_LOB.READ(l_Blob,l_amount,l_pos,l_buffer);

        UTL_FILE.PUT_RAW(l_file,l_buffer,TRUE); 

        l_pos:=l_pos+l_amount; 

      end loop; 

      utl_file.fclose(l_file); 

    end loop;  

    exception 

        when others then 

        if utl_file.is_open(l_file) then 

        utl_file.fclose(l_file); 

        end if; 

END;