I have a value of type java.util.Date which was obtained from a legacy third-party API. Is there a direct way of converting it to kotlinx.datetime.LocalDateTime? I know how to do it only in a roundabout way, such as serializing to String and deserializing, or by converting to java.time.LocalDateTime first and then to the wanted type.
i Think the best thing you can do is to convert it to a string and than convert into a kotlinx.datetime.LocalDateTime
The problem is that not all java types can be converted directly into a kotlin one especially not with the old DataType java.util.Date.
It is also posible with the new DataType java.time.LocalDateTime.
Related
Is there any significant performance difference between the following two?
String json = mapper.writeValueAsString(searchResult);
response.getWriter().write(json);
vs
mapper.writeValue(response.getWriter(), searchResult);
writeValueAsString JavaDoc says:
Method that can be used to serialize any Java value as a String.
Functionally equivalent to calling writeValue(Writer,Object) with
StringWriter and constructing String, but more efficient.
So, in case, you want to write JSON to String is much better to use this method than writeValue. Both these methods use _configAndWriteValue.
In your case it is better to write JSON directly to response.getWriter() than generating String object and after that writing it to response.getWriter().
In the Bond C# manual, it notes the following:
These following changes will break wire compatibility and are not recommended:
Adding or removing required fields
Incompatible change of field types (any type change not covered above); e.g.: int32 to string, string to wstring
...
But it doesn't explain why. The use case here is that I'm using Bond that connects a C# application with a C++ backend. The field is currently a string. I want to change it to a wstring. The manual notes that C# strings can handle C++ strings and C++ wstrings. Therefore, why I can't I just change the field type from string to wstring? Why does this break wire compat?
In Bond's binary formats, strings are UTF8 encoded (no BOM) and wstrings are UTF16-LE encoded. If you were to switch a field from string to wstring, the reading side would try to interpret UTF8 data as UTF16-LE data. These two encodings are not compatible with each other, hence a field type change from string to wstring is a breaking change.
Note that the manual says "For example C# string can represent either Bond type string or wstring." It does not say anything about C++ types. When working with Bond across C# and C++, there are three type systems: Bond's, C#'s, and C++'s.
If on the C++ side, you want to use something akin to std::wstring to store the field in memory, take a look as using Custom type mapping with the string concept.
I'm using Authorize.net API and they require card expiration field to be formated as "yyyy-mm". We did that with this simple line of code:
expirationDate = model.Year.ToString("D4") & "-" & model.Month.ToString("D2")
and this absolutelly worked. I still have cards stored in the system that were saved using this method! But today I was testing something completelly unrelated, and wanted to add another card, and bam, this code exploded with this exception:
System.InvalidCastException: 'Conversion from string "D4" to type 'Integer' is not valid.'
Inner exception to that one is:
Input string was not in a correct format.
This just... doesn't make sense to me. Why in the world is it trying to convert format specifier (D4) into an integer? What input string? What in the world changed in two days?
The problem is that your are using a Nullable(Of Integer). This is a different structure that does not support the overloads of the ToString method a normal Integer has.
You can view the overloads of the Nullable structure here.
I suggest you use the GetValueOrDefault() method to get the proper Integer and also apply the value you expect in case the value is Nothing.
If it is impossible that a instance with a Nothing set for the year reaches this method you can simply use the Value property.
I still do not fully understand why you get this strange error message. Maybe you could check out what the actual method that is called is? Pointing at the method should give you that information. It can't be Nullable(Of Integer).ToString
Well, I found a workable solution and something of an answer thanks to #Nitram's comment. The type of Year/Month property has been changed from Integer to Integer?. Obviously, this isn't a very satisfying answer because I still don't understand why the nullable int can't be formatted, and yet the code compiles perfectly. The working solution for me has been using static format method on String as so:
expirationDate = String.Format("{0:D4}-{1:D2}", model.Year, model.Month)
This works fine even with nullable types.
I must create a DAO with hibernate that can work in a generic way, that means to execute some queries based on properties types.
My generic DAO works ok when filtering String properties of any class, it accepts "contains", "starts with", "ends with" using "like" restrictions:
Restrictions.like(propertyName, (String) value, getMatchMode());
The problem I have is that I need to also create a similar "contains", "starts with", "ends with" to bytes (byte[]) properties, the hibernate
SimpleExpression like(String propertyName, Object value)
api does not work (probably totally expected not to work), so I was thinking maybe I could convert the bytes stored in DB into a String, and then with a workaround apply the normal stringed Restrictions.like api.
The problem is that I think there's no standard way to convert bytes[] into String since there's no standard data type among DB platforms, I mean, Oracle uses "RAW", hsql uses "VARBINARY" and so on (Oracle uses its own RAWTOHEX for instance).
Or should any of you have an idea how to sort out the problem it will be very welcome.
Cheers.
///RGB
In MySQL you could use HEX to convert BINARY to String. i.e.
SELECT
*
FROM
myTable
WHERE
HEX(myBinaryField) LIKE 'abc%'`
In your Java code you could use some Base64 Encoder, which will convert bytes to string. Then you could just persist the Base64 encoded String and use normal LIKE queries. Maybe not the most efficient way, but it should work well.
I foundout that scalaquery uses java.sql.date as the date object. But it drops time when I create java.sql.date.
Is there any way that I can use to create mysql datetime field in scalaquery?
There is no java.util.Date support in ScalaQuery. However, it's possible to enhance ScalaQuery with your own type mappers. For java.util.Date such a wrapper could look like this
implicit val JavaUtilDateTypeMapper = MappedTypeMapper.base[java.util.Date, Long] (_.getTime, new java.util.Date(_))
converting the java.util.Date into a simple Long. It depends on your database what's the best target, in my case a Long works perfectly.
Instead of using java.sql.Date, try using java.sql.Timestamp, when declaring the column.
It looks like that yields a better mapping for a column with both date and time elements.