为减少导入时产生的错误，导入前先运行下面脚本：

DECLARE
  TYPE T_VARCHAR_TAB IS TABLE OF VARCHAR2(32767) INDEX BY BINARY_INTEGER;
  V_PRIVS_STR  T_VARCHAR_TAB;
  V_ROLE_STR   T_VARCHAR_TAB;
  V_DROP_STR   VARCHAR2(32767);
  V_CREATE_STR VARCHAR2(32767);
BEGIN
  FOR I IN (SELECT USERNAME
              FROM DBA_USERS
             WHERE USERNAME NOT IN
                   ('SYS', 'SYSTEM', 'DBSNMP', 'WMSYS', 'ORDSYS', 'OE')) LOOP
 
    SELECT DBMS_METADATA.GET_DDL('USER', I.USERNAME)
      INTO V_CREATE_STR
      FROM DUAL;
    SELECT 'GRANT ' || PRIVILEGE || ' ON ' || OWNER || '.' || TABLE_NAME ||
           ' TO ' || GRANTEE BULK COLLECT
      INTO V_PRIVS_STR
      FROM DBA_TAB_PRIVS
     WHERE GRANTEE = I.USERNAME;
 
    SELECT 'GRANT ' || GRANTED_ROLE || ' TO ' || GRANTEE BULK COLLECT
      INTO V_ROLE_STR
      FROM DBA_ROLE_PRIVS
     WHERE GRANTEE = I.USERNAME;
    SELECT 'DROP USER ' || I.USERNAME || ' CASCADE'
      INTO V_DROP_STR
      FROM DUAL;
 
    EXECUTE IMMEDIATE V_DROP_STR;
    EXECUTE IMMEDIATE V_CREATE_STR;
    FOR I IN 1 .. V_PRIVS_STR.COUNT LOOP
      BEGIN
        EXECUTE IMMEDIATE V_PRIVS_STR(I);
      EXCEPTION
        WHEN OTHERS THEN
          NULL;
      END;
    END LOOP;
    FOR I IN 1 .. V_ROLE_STR.COUNT LOOP
      EXECUTE IMMEDIATE V_ROLE_STR(I);
    END LOOP;
  END LOOP;
END;
/

详细内容看YANGTINGKUN的博客：

      http://space.itpub.net/4227/viewspace-69014