Flutter中如何从接口返回结果中提取access_token值

Got it, let's walk through how to pull that access_token out of the JSON response. First, you'll need to parse the raw response string into a Dart map so you can access the token by its key. Here's what you need to do:

Step 1: Add the JSON parsing import #

First, make sure you have this import at the top of your Dart file to handle JSON decoding:

import 'dart:convert';

Step 2: Modify your request to parse the response #

You can update your existing code in two ways—either keeping the .then() chain or switching to async/await (which is cleaner since you already marked the function as async).

Option 1: Using .then() (keeping your original structure) #

Future<Null> getData() async { 
  var url = "http://192.168.1.23:7070/api/v2/token"; 
  http.post(url, body:{ 
    "grant_type": "string", 
    "branchcode": "string", 
    "password": "string", 
    "username": "string", 
    "dbname": "string", 
    "dbuser": "string", 
    "dbpassword": "string", 
    "dbtype": "string" 
  }).then((response){ 
    print("Response Status: ${response.statusCode}"); 
    // Only parse if the request succeeded (status code 200)
    if (response.statusCode == 200) {
      // Convert the raw JSON string to a Dart Map
      Map<String, dynamic> jsonResponse = jsonDecode(response.body);
      // Extract the access_token by its key
      String accessToken = jsonResponse['access_token'];
      print("Extracted Access Token: $accessToken");
      // Now you can store this token (e.g., in SharedPreferences) or use it for other requests
    } else {
      print("Request failed with status: ${response.statusCode}");
    }
  }).catchError((error) {
    print("Error making request: $error");
  }); 
}

Option 2: Using async/await (cleaner, more readable) #

Since your function is already marked async, using await makes the code flow more linearly and easier to debug:

Future<Null> getData() async { 
  try {
    var url = "http://192.168.1.23:7070/api/v2/token"; 
    var response = await http.post(url, body:{ 
      "grant_type": "string", 
      "branchcode": "string", 
      "password": "string", 
      "username": "string", 
      "dbname": "string", 
      "dbuser": "string", 
      "dbpassword": "string", 
      "dbtype": "string" 
    });

    print("Response Status: ${response.statusCode}"); 
    if (response.statusCode == 200) {
      Map<String, dynamic> jsonResponse = jsonDecode(response.body);
      String accessToken = jsonResponse['access_token'];
      print("Extracted Access Token: $accessToken");
      // Use or store the token here
    } else {
      print("Request failed with status: ${response.statusCode}");
    }
  } catch (error) {
    print("Error occurred: $error");
  }
}

Key Notes: #

• Always check the response status code first (like 200 OK) before parsing—this avoids trying to decode error responses that might not be valid JSON.
• The jsonDecode() function converts the raw string response into a Map<String, dynamic>, which lets you access values using their JSON keys (like 'access_token').
• Once you have the token, you can store it (e.g., using the shared_preferences package) to reuse it in future API calls instead of requesting a new one every time.

内容的提问来源于stack exchange，提问作者Kaan Karamanoğlu