java利用反射扩展任意数组的方法

    public static Object goodCopyOf(Object a,int newLength){//该方法可以 用来扩展任意类型的数组
        Class cl =  a.getClass();
        if (!cl.isArray()) return null;
        Class componentType = cl.getComponentType();
        int length = java.lang.reflect.Array.getLength(a);
        Object newArray = java.lang.reflect.Array.newInstance(componentType,newLength);
        System.arraycopy(a,0,newArray,0,Math.min(length,newLength));
        return  newArray;
    }