Java Reflection - Method not found

Question

I am trying to find the method of a PreparedStatement (ps):

Method method = ps.getClass().getMethod("setLong", int.class, Class.forName("java.lang.Long"));
method.setAccessible(true);
method.invoke(ps, fieldIndex, value);

but it isn't found. I have to use Class.forName("java.lang.Long") instead of Long.class.

For String it works:

Method method = ps.getClass().getMethod("setString", int.class, Class.forName("java.lang.String"));
method.setAccessible(true);
method.invoke(ps, fieldIndex, value);

What am I doing wrong? Any idea? Is the namespace of Long wrong?

Why on earth would you use reflection, if you already have all values in hand? Simply call ps.setLong(fieldIndex, value). — Seelenvirtuose
– Seelenvirtuose, Commented Mar 6, 2018 at 10:13
@Seelenvirtuose maybe (one can always hope) this is one of those Minimal, Complete, and Verifiable examples the legends talk about. And the setAccessible call indicates that those methods are not visible to the calling code. But they are, so maybe MrSct just thought they weren't :/ — Malte Hartwig
– Malte Hartwig, Commented Mar 6, 2018 at 10:21
I have a string variable that tells me which type have to use like that: Method method = ps.getClass().getMethod("set"+ methodType, int.class, Class.forName(getFullNameClass(methodType))); — MrScf
– MrScf, Commented Mar 6, 2018 at 10:45
That still sounds like an xy problem. The actual type is determined by the statement or target column and whatever set… method you will use, the driver will attempt to convert the argument to the target type. It would be very strange, if you can’t just use setObject(int,Object) or setObject(int,Object,type:int)… — Holger
– Holger, Commented Mar 12, 2018 at 12:37

assylias · Accepted Answer · 2018-03-06 10:10:07Z

10

The second argument is a long, not a Long:

Method method = ps.getClass().getMethod("setLong", int.class, long.class);

Also, for a String, you don't need to call Class.forName("java.lang.String"): String.class would work as well.

But as commented, if you already have a PreparedStatement instace, you could simply call:

ps.setLong(fieldIndex, value);

answered Mar 6, 2018 at 10:10

assylias

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