Java 8 Lambda将Number [] []转换为double [] []

Number[][] intArray = new Integer[][]{ {1, 2, 3}, {4, 5, 6}, {7, 8, 9} };
double[][] doubleArray = Arrays.stream(intArray)
                            .forEach(pArray -> Arrays.stream(pArray)
                                                .mapToDouble(d ->d.doubleValue())
                                                .toArray())
                            .toArray();
Number[][] intArray = new Integer[][]{ {1, 2, 3