在post请求时表示空值

fetch('https://example.com/api', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    name: 'John',
    age: null, // 表示空值
    email: ''   // 表示空字符串
  })
});

import requests

url = 'https://example.com/api'
data = {
    'name': 'John',
    'age': None,  # 表示空值
    'email': ''   # 表示空字符串
}

response = requests.post(url, json=data)

import org.springframework.web.client.RestTemplate;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;

public class Example {
    public static void main(String[] args) {
        RestTemplate restTemplate = new RestTemplate();
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);

        String requestBody = "{\"name\":\"John\",\"age\":null,\"email\":\"\"}";
        HttpEntity<String> request = new HttpEntity<>(requestBody, headers);

        restTemplate.postForObject("https://example.com/api", request, String.class);
    }
}

app.post('/api', (req, res) => {
  const { name, age, email } = req.body;
  console.log(name, age, email); // 确保能够正确打印出空值
  res.send('Received');
});