400向Swift中的本地服务器发出post请求时出现错误

var request = URLRequest(url: URL(string: "http://localhost:8080/api")!)
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")

let jsonData = ["key": "value"]
request.httpBody = try? JSONSerialization.data(withJSONObject: jsonData, options: [])

import Foundation

let url = URL(string: "http://localhost:8080/api")!
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")

let jsonData = ["key": "value"]
request.httpBody = try? JSONSerialization.data(withJSONObject: jsonData, options: [])

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    if let error = error {
        print("Error: \(error)")
        return
    }
    
    if let httpResponse = response as? HTTPURLResponse {
        print("Status Code: \(httpResponse.statusCode)")
    }
    
    if let data = data {
        let responseString = String(data: data, encoding: .utf8)
        print("Response: \(responseString ?? "")")
    }
}

task.resume()