@Test
    public void test_1() {
        String json = "{\"a\":14900000000000002396241300002543983538316751946695148944854736328125e-7}";
        A a = JSON.parseObject(json, A.class);
        JSONObject obj = JSON.parseObject(json, JSONReader.Feature.UseBigDecimalForDoubles);

        BigDecimal expected = new BigDecimal("14900000000000002396241300002543983538316751946695148944854736328125e-7");
        assertEquals(expected, a.a); //失败
        assertEquals(obj.get("a"), a.a); //失败
    }

    @Test
    public void test_2() {
        String json = "{\"a\":12345678901234567890123456789012345678e-10}";
        A a = JSON.parseObject(json, A. class);
        JSONObject obj = JSON.parseObject(json, JSONReader.Feature.UseBigDecimalForDoubles);

        BigDecimal expected = new BigDecimal("12345678901234567890123456789012345678e-10");
        assertEquals(expected, a.a); //成功
        assertEquals(obj.get("a"), a.a); //失败
    }
    
    public static class A {
        public BigDecimal a;
    }