如何在Flutter中使用http.post并作为String Json对象发送

dependencies:
  http: ^0.13.3

import 'package:http/http.dart' as http;

import 'package:http/http.dart' as http;

void main() {
  final url = Uri.parse('https://example.com/api/endpoint');
  final headers = {'Content-Type': 'application/json'};
  final jsonBody = '{"key": "value"}';

  http.post(url, headers: headers, body: jsonBody).then((response) {
    if (response.statusCode == 200) {
      print('Request successful');
      print('Response body: ${response.body}');
    } else {
      print('Request failed with status: ${response.statusCode}');
    }
  }).catchError((error) {
    print('Error occurred: $error');
  });
}