@Override
    public ConstantParam apply(ConstantParam constantParam) {
        return new ConstantParam(String.format("%s(%s, %s)", getName(),
                constantParam.format(), key.format()));
    }
JsonGetterFunction constructor

@param field the field to be extracted
@param key the key of the field in the json
inlong-sort/sort-common/src/main/java/org/apache/inlong/sort/protocol/transformation/function/JsonGetterFunction.java