未处理的异常："字符串"类型不是"列表<dynamic>"类型的子类型

Question

我之前使用AWS Lambda和API网关创建了一个API，该网关从我的DynamoDB表中获取数据。

这是我的lambda函数

const AWS = require("aws-sdk");
const documentClient = new AWS.DynamoDB.DocumentClient();
exports.handler = async event => {
const params = {
TableName: "//tableName" 
};
try {
// Utilising the scan method to get all items in the table
const data = await documentClient.scan(params).promise();
const response = {
statusCode: 200,
body: JSON.stringify(data.Items)
};
return response;
} catch (e) {
return {
statusCode: 500
};
}
};

以下是来自API的示例响应。

{"statusCode":200,"body":"[{"product":"clear","__typename":"ProductModel","size":"small","_lastChangedAt":1625829002606,"_version":1,"company":"add","updatedAt":"2021-07-09T11:10:02.578Z","category":"Pot","createdAt":"2021-07-09T11:10:02.578Z","price":"69","description":"this doesn't even make sense","id":"f4acb29c-f8f3-4765-abf6-aef0002a837c"},{"product":"product","__typename":"ProductModel","size":"1","_lastChangedAt":1625988107746,"_version":1,"company":"company","updatedAt":"2021-07-11T07:21:47.704Z","category":"Climbers","createdAt":"2021-07-11T07:21:47.704Z","price":"221","description":"description","id":"0a51d3c3-4df3-4549-abaa-f8b88e8ac407"}]"}
{"mode":"full","isActive":false}

现在，当我完成解码响应正文的常规步骤时。我将此错误作为未处理的异常：类型"String"不是类型"List"的子类型。以下是我的做法

void getProductData() async {
List list ;
var response = await http.get(Uri.parse('//api-endpoint'));
Map<String,dynamic> map  = json.decode(response.body);
list = map["body"];
}

解码的JSON响应

{statusCode: 200, body: [{"product":"clear","__typename":"ProductModel","size":"small","_lastChangedAt":1625829002606,"_version":1,"company":"add","updatedAt":"2021-07-09T11:10:02.578Z","category":"Pot","createdAt":"2021-07-09T11:10:02.578Z","price":"69","description":"this doesn't even make sense","id":"f4acb29c-f8f3-4765-abf6-aef0002a837c"},{"product":"product","__typename":"ProductModel","size":"1","_lastChangedAt":1625988107746,"_version":1,"company":"company","updatedAt":"2021-07-11T07:21:47.704Z","category":"Climbers","createdAt":"2021-07-11T07:21:47.704Z","price":"221","description":"description","id":"0a51d3c3-4df3-4549-abaa-f8b88e8ac407"}]
}

Answer 1

你能试试下面的几行吗？

--第一个解决方案看起来是正确的，但我已经改进了一点。让我们朝这个方向走吧。

void getProductData() async {
List<Map<String,dynamic>> list;
final response = await http.get(Uri.parse('//api-endpoint'));
Map<String,dynamic> map  = json.decode(response.body);
final body = map['body'];

if(body is List){
list = List.from(map["body"] as List<Map<String,dynamic>>);
}else {
print('Body is'nt List');
}
}