Question

有没有办法配置gson来忽略未知的枚举值？对于示例

在我的客户端代码中有一个枚举DeviceType有2个枚举值：PC， MOBILE

但是当服务器被发送另一种类型，例如MAC作为另一种类型设备类型。如何配置我的gson deserilalizer来设置 DeviceType = null而不是抛出异常？

谢谢，

肖恩

Answer 1

您可以轻松编写忽略未知值的自定义JsonDeserializer。阅读更多here。有关起点，请查看源gson源代码，类com.google.gson.DefaultTypeAdapters.EnumTypeAdapter

Answer 2

现在我们可以使用可为空的枚举类型，例如：

data class SomeDTO (
    val type : DeviceType?,
    //other values
)

在这种情况下，解析不会有任何异常。

Answer 3

我不能100％确定这是否可行，但您可以在枚举上声明一个lazy var persistentContainer: NSPersistentContainer = { /* The persistent container for the application. This implementation creates and returns a container, having loaded the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail. */ let container = NSPersistentContainer(name: "CoreTest3") let description = NSPersistentStoreDescription() description.shouldInferMappingModelAutomatically = true description.shouldMigrateStoreAutomatically = true container.persistentStoreDescriptions = [description] container.loadPersistentStores(completionHandler: { (storeDescription, error) in if let error = error as NSError? { // Replace this implementation with code to handle the error appropriately. // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. /* Typical reasons for an error here include: * The parent directory does not exist, cannot be created, or disallows writing. * The persistent store is not accessible, due to permissions or data protection when the device is locked. * The device is out of space. * The store could not be migrated to the current model version. Check the error message to determine what the actual problem was. */ fatalError("Unresolved error \(error), \(error.userInfo)") } }) return container }()方法来覆盖默认实现，其中一个为未知值而不是IllegalArgumentException返回null。

documentation建议使用重写的静态实现。

然后它只取决于Gson如何处理该方法的结果（假设Gson甚至使用该方法进行解析），但它是一个简单的解决方法，值得一试。

Gson忽略未知的枚举值

3 个答案: