java中从1970-1-1到当前时间之间的毫秒数转换为oracle date

select sessiontimezone,dbtimezone,sysdate,current_date from dual;

CREATE OR REPLACE PACKAGE cux_time_utils_pkg IS

    FUNCTION unix_timestamp_to_utc_date(in_unix_timestamp IN NUMBER) RETURN DATE DETERMINISTIC;

    FUNCTION unix_timestamp_to_session_date(in_unix_timestamp IN NUMBER) RETURN DATE DETERMINISTIC;

    FUNCTION date_to_unix_timesecond(in_date IN DATE) RETURN NUMBER DETERMINISTIC;

    FUNCTION date_to_unix_times_millis(in_date IN DATE) RETURN NUMBER DETERMINISTIC;

    FUNCTION java_currenttimemillis RETURN NUMBER;

    FUNCTION current_unix_times_millis RETURN NUMBER DETERMINISTIC;
END; 

CREATE OR REPLACE PACKAGE BODY cux_time_utils_pkg IS

    --return utc0 date
    --返回0时区时间
    FUNCTION unix_timestamp_to_utc_date(in_unix_timestamp IN NUMBER) RETURN DATE DETERMINISTIC IS
        v_date DATE;
    BEGIN
        v_date := to_date(‘1970-01-01‘,
                          ‘yyyy-mm-dd‘) + in_unix_timestamp / 1000 / 60 / 60 / 24;
        RETURN v_date;
    END;

    --return sessiontimezone date
    --返回当前回话时区时间
    --select sessiontimezone,dbtimezone,sysdate,current_date from dual;
    FUNCTION unix_timestamp_to_session_date(in_unix_timestamp IN NUMBER) RETURN DATE DETERMINISTIC IS
        v_date DATE;
    BEGIN
        v_date := to_date(‘1970-01-01‘,
                          ‘yyyy-mm-dd‘) + in_unix_timestamp / 1000 / 60 / 60 / 24 +
                  to_number(substr(tz_offset(sessiontimezone),
                                   1,
                                   3)) / 24;
        RETURN v_date;
    END;

    --返回1970-01-01 00:00:00到in_date之间的秒数
    FUNCTION date_to_unix_timesecond(in_date IN DATE) RETURN NUMBER DETERMINISTIC IS
        v_unix_timestamp NUMBER;
    BEGIN
        v_unix_timestamp := (in_date - to_date(‘1970-01-01‘,
                                               ‘yyyy-mm-dd‘)) * 60 * 60 * 24;
        RETURN v_unix_timestamp;
    END;

    --返回1970-01-01 00:00:00到in_date之间的毫秒数
    --此方法不够精确，因为in_date精度为秒，所以返回值的精度为千毫秒
    --可调整入参结构为timestamp,再进行优化
    FUNCTION date_to_unix_times_millis(in_date IN DATE) RETURN NUMBER DETERMINISTIC IS
        v_unix_timestamp NUMBER;
    BEGIN
        v_unix_timestamp := (in_date - to_date(‘1970-01-01‘,
                                               ‘yyyy-mm-dd‘)) * 1000 * 60 * 60 * 24;
        RETURN v_unix_timestamp;
    END;

    --返回java的当前毫秒数
    FUNCTION java_currenttimemillis RETURN NUMBER AS
        LANGUAGE JAVA NAME ‘java.lang.System.currentTimeMillis() return java.lang.Integer‘;


    --返回当前时间的毫秒数
    FUNCTION current_unix_times_millis RETURN NUMBER DETERMINISTIC IS
        v_unix_timestamp NUMBER;
    BEGIN
        v_unix_timestamp := extract(DAY FROM(systimestamp - to_timestamp(‘1970-01-01‘,
                                                                     ‘YYYY-MM-DD‘))) * 1000 * 60 * 60 * 24 +
                            to_number(to_char(sys_extract_utc(systimestamp),
                                              ‘SSSSSFF3‘));
        RETURN v_unix_timestamp;
    END;

END;