使用Decodable链接多个JSON请求- Swift 5

import Foundation

struct User: Decodable {
    let id: Int
    let name: String
    // 其他属性...
}

func fetchUsers(completion: @escaping ([User]?) -> Void) {
    let url1 = URL(string: "https://example.com/users1.json")!
    let url2 = URL(string: "https://example.com/users2.json")!

    let group = DispatchGroup()
    var users: [User] = []

    group.enter()
    URLSession.shared.dataTask(with: url1) { data, response, error in
        defer { group.leave() }

        if let error = error {
            print("Error: \(error)")
            completion(nil)
            return
        }

        guard let data = data else {
            print("No data received")
            completion(nil)
            return
        }

        do {
            let decodedUsers = try JSONDecoder().decode([User].self, from: data)
            users.append(contentsOf: decodedUsers)
        } catch {
            print("Error decoding JSON: \(error)")
            completion(nil)
        }
    }.resume()

    group.enter()
    URLSession.shared.dataTask(with: url2) { data, response, error in
        defer { group.leave() }

        if let error = error {
            print("Error: \(error)")
            completion(nil)
            return
        }

        guard let data = data else {
            print("No data received")
            completion(nil)
            return
        }

        do {
            let decodedUsers = try JSONDecoder().decode([User].self, from: data)
            users.append(contentsOf: decodedUsers)
        } catch {
            print("Error decoding JSON: \(error)")
            completion(nil)
        }
    }.resume()

    group.notify(queue: .main) {
        completion(users)
    }
}

// 调用示例
fetchUsers { users in
    if let users = users {
        // 处理获取到的用户数据
        print(users)
    } else {
        // 处理错误情况
        print("Failed to fetch users")
    }
}