Swift JSONDecoder 类型不匹配错误

swift
struct User: Codable {
    let name: String
    let age: Int
}
let jsonString = """
{
    "name": "John",
    "age": 25
}
"""
let jsonData = jsonString.data(using: .utf8)!
let decoder = JSONDecoder()
do {
    let user = try decoder.decode(User.self, from: jsonData)
    print(user)
} catch {
    print("Failed to decode JSON: \(error)")
}