以下是oracle中Blob、Clob、Varchar之间的互相转换（都是百度找的，亲测可用）
Blob转Varchar2:
CREATE OR REPLACE FUNCTION blob_to_varchar (blob_in IN BLOB)RETURN VARCHAR2ISv_varchar VARCHAR2(4000);v_start PLS_INTEGER := 1;v_buffer PLS_INTEGER := 4000;BEGIN--select userenv(LANGUAGE) into g_nls_db_char from dual; if DBMS_LOB.GETLENGTH(blob_in) is null thenreturn empty_clob();end if;DBMS_OUTPUT.put_line(TEST: || CEIL(DBMS_LOB.GETLENGTH(blob_in)));--DBMS_LOB.CREATETEMPORARY(v_clob, TRUE);FOR
