Iterating over a hashMap key changes to BigDecimal

Question

My issue is this, I have hashMap

//for (String tablaBuscar : listaTablas) {
        // RECUPERAR REGISTROS POR TABLA
    HashMap<String,String> listaRegistros =(HashMap<String,String>) RequerimientosTablaDestino
                .getListaLineasPorTablaYColumna(idCabecera,idCriterio);

when I want to iterate (I have tried several ways, this is the last one)

Iterator<String>  entradaMap =  listaRegistros.keySet().iterator();
Iterator<String> valorMap =  listaRegistros.values().iterator();
while(entradaMap.hasNext()&&valorMap.hasNext()) {
    String elemento=entradaMap.next().toString();
    int registro =(Integer.parseInt(elemento));
    String tablaBuscar = (String)valorMap.next();

in "int registro" line I get "cannot cast from BigDecimal to Int" Debugging I have seen that ALLWAYS the key of the hash map is "big decimal type", no matter the way I have created it.

If I try to use it as a BigDecimal as seen in debugging time, I get compilations failures because "type missmatch" "cannot cast" etc...

So the compiler thinks that the key is the type I have put, but at runtime the program thinks that te key is allways a bigDecimal.

Any idea? thanks

Please post a short but *complete* program demonstrating the problem. I can't see how you'd get the problem you're reporting on the line you're reporting it... — Jon Skeet, Nov 02 '15 at 14:03

score 0 · Answer 1 · answered Nov 02 '15 at 14:00

If your key set only contains String values parseable as BigDecimal, you can easily retrieve an actual BigDecimal object from the keys by iterating them and using the constructor taking a String argument:

for (String key: myMap.keySet()) {
    BigDecimal converted = new BigDecimal(key);
}

Also as shown, no need for a double iteration through Iterator on both keys and values.

If you want an additional layer of validation, you can catch a NumberFormatException when initializing your BigDecimal, e.g. new BigDecimal("foo") would throw one.

Also, you can retrieve the integer value of your BigDecimal objects by invoking BigDecimal#intValue or BigDecimal.intValueExact.

Thanks, guys. The issue happened because ibatis parametrization has not the java type in resultMap. And (Idon't know why) it takes key as BigDecimal when is declared as String. — Miguel Abreu, Nov 02 '15 at 15:35

score 0 · Answer 2 · answered Mar 11 '16 at 17:56

I just ran into this same issue. Miguel alluded to the solution in his comment on Mena's answer, but to be more explicit the fix involves adding a parameter to your result mapper to force the return of a String:

<resultMap type="java.util.HashMap" id="dataTypeMap">
    <result column="DATA_TYPE_ID" javaType="java.lang.String" property="id" />
    <result column="DATA_TYPE" property="name" />
</resultMap>

Iterating over a hashMap key changes to BigDecimal

2 Answers2