写在前面,由于苹果公司对CoreData的改动，使得在Xcode8.0和ios10.0以上环境下使用新语法使用CoreData不兼容ios9以下系统，本实例主要简单介绍Swift3.0中CoreData的使用，同时处理了不兼容ios9以下版本系统的问题。

开发环境：Xcode8.1，iOS10.0

说明：本实例为swift纯代码编写

下面为实例的主要实现代码：

AppDelegate.swift

import UIKit  
import CoreData 
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
   var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    //创建导航视图为主界面
    window = UIWindow(frame:UIScreen.main.bounds);
    window?.backgroundColor = UIColor.white;
    let nav = UINavigationController(rootViewController: ViewController());
    window?.rootViewController = nav;
    window?.makeKeyAndVisible();
    return true
}

 //省略......

func applicationWillTerminate(_ application: UIApplication) {
    if #available(iOS 10.0, *) {
        self.saveContext()
    } else {
    }
}

// MARK: - Core Data stack
@available(iOS 10.0 , *)
lazy var persistentContainer: NSPersistentContainer = {
    let container = NSPersistentContainer(name: "saveDataDemo")
    container.loadPersistentStores(completionHandler: { (storeDescription, error) in
        if let error = error as NSError? {
            fatalError("Unresolved error \(error), \(error.userInfo)")
        }
    })
    return container
}()

lazy var applicationDocumentsDirectory: URL = {
    let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
    return urls[urls.count-1]
}()
//iOS9下的 Core Data stack
lazy var managedObjectModel: NSManagedObjectModel = {
    let modelURL = Bundle.main.url(forResource: "saveDataDemo", withExtension: "momd")!
    return NSManagedObjectModel(contentsOf: modelURL)!
}()

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
    let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = self.applicationDocumentsDirectory.appendingPathComponent("SingleViewCoreData.sqlite")
    var failureReason = "There was an error creating or loading the application's saved data."
    do {
        try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: nil)
    } catch {
        // Report any error we got.
        var dict = [String: AnyObject]()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" as AnyObject?
        dict[NSLocalizedFailureReasonErrorKey] = failureReason as AnyObject?
        
        dict[NSUnderlyingErrorKey] = error as NSError
        let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
        NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
        abort()
    }
    
    return coordinator
}()

lazy var managedObjectContext: NSManagedObjectContext = {
    let coordinator = self.persistentStoreCoordinator
    var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
    managedObjectContext.persistentStoreCoordinator = coordinator
    return managedObjectContext
}()
  //iOS9下的 Core Data stack结束
// MARK: - Core Data Saving support
@available(iOS 10.0 , *)
func saveContext () {
    let context = persistentContainer.viewContext
    if context.hasChanges {
        do {
            try context.save()
        } catch {
            // 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.
            let nserror = error as NSError
            fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
        }
    }
}

}

ViewController.swift

import UIKit
import CoreData
class ViewController: UIViewController , UITextFieldDelegate{
var mycontext : NSManagedObjectContext!;
var  mynum , myname , myage : UITextField!;

override func viewDidLoad() {
    if #available(iOS 10.0, *) {
        mycontext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
        
    } else {
        print("IOS9");
        mycontext = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
    }
    super.viewDidLoad()
   
   //此处省略界面创建代码详细请看源文件
    //添加事件实现隐藏键盘
    let tap = UITapGestureRecognizer(target: self, action: #selector(tap(G:)));
    self.view.addGestureRecognizer(tap);
}
//界面跳转
func showData(){
    navigationController?.pushViewController(showViewController(), animated: true);
}

//隐藏键盘
func tap(G:UITapGestureRecognizer) {
    self.view.endEditing(true);
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    self.view.endEditing(true);
    return true;
}

//保存数据到CoreData
func SavaDataToCoredata(){
    do{
        let inserInfo = NSEntityDescription.insertNewObject(forEntityName: "MyStudents", into: mycontext);
        if(mynum.text != "" && myname.text != "" && myage.text != ""){
            inserInfo.setValue(Int(mynum.text!), forKey: "num");
            inserInfo.setValue("\(myname.text!)", forKey: "name");
            inserInfo.setValue(Int(myage.text!), forKey: "age");
            try mycontext.save()
            mynum.text = "";
            myname.text = "";
            myage.text = "";
            let myAlert = UIAlertController(title: "提示", message: "保存成功", preferredStyle: .alert);
            let myokAction = UIAlertAction(title: "确定", style: .default, handler: nil);
            myAlert.addAction(myokAction);
            self.present(myAlert, animated: true, completion: nil);
            
        }else{
            let myAlert = UIAlertController(title: "提示", message: "请输入完整的信息", preferredStyle: .alert);
            let myOkAction = UIAlertAction(title: "确定", style: .default, handler: nil);
            myAlert.addAction(myOkAction);
            self.present(myAlert, animated: true, completion: nil);
            
        }
        
    }catch{
        fatalError();
    }
}
//清除coreData中的数据
func delCoreData(){
    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "MyStudents");
    do{
        let rels = try mycontext.fetch(request) as! [NSManagedObject];
        for rel in rels{
            mycontext.delete(rel);
        }
        try mycontext.save();
        let myAlert = UIAlertController(title: "提示", message: "清空数据库成功", preferredStyle: .alert);
        let myOkAction = UIAlertAction(title: "确定", style: .default, handler: nil);
        myAlert.addAction(myOkAction);
        present(myAlert, animated: true, completion: nil);
    }catch{
        fatalError();
    }
    
}

}

showViewController.swift

import UIKit;
import CoreData;
class showViewController: UIViewController {
let fullsize = UIScreen.main.bounds.size;
let myEntity = "Students";
var myContext : NSManagedObjectContext!;
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "MyStudents");
var myTextView : UITextView!;
override func viewDidLoad() {
    if #available(iOS 10.0, *) {
        myContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
        
    } else {
        myContext = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
    }
    super.viewDidLoad()

    self.title = "显示数据";
    self.view.backgroundColor = UIColor.white;
    
    myTextView = UITextView(frame: CGRect(x: 0, y: 0, width: fullsize.width, height: fullsize.height));
    myTextView.center = CGPoint(x: fullsize.width * 0.5, y: fullsize.height * 0.5);
    myTextView.textAlignment = .left;
    myTextView.textColor = UIColor.red;
    myTextView.isEditable = false;
    self.view.addSubview(myTextView);
    show();
}

func show(){
    do{
        let rels = try myContext.fetch(request) as! [NSManagedObject];
        var re = "";
        for rel in rels {
            if rel.value(forKey: "name") != nil{
                re += "\n学号：000\(rel.value(forKey: "num")!)\n" + "姓名： \(rel.value(forKey: "name")!)\n" + "年龄： \(rel.value(forKey: "age")!)\n";
            }
        }
        if re != ""{
            myTextView.text = re;
        }else{
            myTextView.text = "未找到相关数据！";
            myTextView.textColor = UIColor.red;
        }
    }catch{
        fatalError();
    }
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}

下面是程序运行效果图

未命名.png

源码地址：https://github.com/pkx0128/saveDataDemo.git