plsql 将blob格式数据导出到rtf文件

create or replace directory file_dir as 'E:\test';

declare
i_blob blob;
file_handle utl_file.file_type;
v_pathna varchar2(30);
i_blob_len INTEGER;
i_amount binary_integer:=32767;
i_pos integer:=1; 
i_buffer raw(32767); 
str_bdnm varchar2(40);
cursor cur_rec is select * from ZZLL_BD_LSYG;
recur ZZLL_BD_LSYG%ROWTYPE; 

begin
  open cur_rec;
  loop 
    fetch cur_rec into recur;
    exit when cur_rec%NOTFOUND;
    str_bdnm:= recur.BDNM; 
    select LSYG into i_blob from ZZLL_BD_LSYG where BDNM=str_bdnm;
    dbms_lob.open(i_blob,dbms_lob.lob_readonly);
    file_handle := utl_file.fopen('FILE_DIR',str_bdnm||'.rtf','wb',32767);
    i_blob_len := dbms_lob.getlength(i_blob);
    while i_pos < i_blob_len loop
        DBMS_LOB.read(i_blob,i_amount,i_pos,i_buffer);
        utl_file.put_raw(file_handle,i_buffer,true); 
        i_pos:=i_pos+i_amount; 
    end loop;
    i_pos :=1;
    dbms_lob.close(i_blob);
    utl_file.fclose(file_handle);
  end loop;
end;

代码中主要使用游标cursor 对数据库中的行读取选择其中的列，utl_file工具包完成文件的打开，写入，关闭操作。
操作数据表ZZLL_BD_LSYG