public static String maskJson(String input, String key) {
        if(input == null)
            return null;
        DocumentContext ctx = JsonPath.parse(input);
        return maskJson(ctx, key);
    }
@Test
    public void testMaskRequestBody() {
        String input = "{\"name\":\"Steve\",\"contact\":{\"phone\":\"416-111-1111\"},\"password\":\"secret\"}";
        String output = Mask.maskJson(input, "test1");
        System.out.println(output);
        Assert.assertEquals(JsonPath.parse(output).read("$.contact.phone"), "************");
        Assert.assertEquals(JsonPath.parse(output).read("$.password"), "******");
        Assert.assertEquals(output, "{\"name\":\"Steve\",\"contact\":{\"phone\":\"************\"},\"password\":\"******\"}");
    }