Conversion between nsdate of Objective-c Foundation and nsstring, long type

1, NSString converted into nsdate

    NSString *datestr = "2013-6-3 14:58:00";
    NSDateFormatter *format=[[nsdateformatter alloc] init];
    [Format setdateformat:@ "Yyyy-mm-dd HH:mm:ss"];
    NSDate *date=[format DATEFROMSTRING:DATESTR];
    

2, NSDate converted into Longlong type

    Nstimeinterval time = [date timeIntervalSince1970];
    Long Long dTime = [[NSNumber numberwithdouble:time] longlongvalue];

3, Longlong type converted into nsdate

    Java Time/1000 is objective-c time long long
    value = [number Longlongvalue]/1000;//number is nsnumber type
    nsnumber * Time = [NSNumber numberwithlonglong:value];
    Convert to Nstimeinterval
    nstimeinterval nstimeinterval = [Time longvalue];
    NSDate *date = [[NSDate alloc] initwithtimeintervalsince1970:nstimeinterval];

4, NSDate type converted into NSString

    NSDate *date = [NSDate date];
    NSDateFormatter *format=[[nsdateformatter alloc] init];
    [Format setdateformat:@ "Yyyy-mm-dd HH:mm:ss"];
    NSString *datestring = [format stringfromdate:date];