Swift 3.0 下使用Coredata以及读写本地文件（兼容

一、创建Coredata有两种方式，一种是创建项目的时候创建，另一种是直接command +N选择Coredata创建

enter description here

二、创建CoreData工具类CodataTool.swift

//
//  CodataTool.swift
//  PricingExcellence
//
//  Created by Mr_怪蜀黍 on 2017/7/11.
//  Copyright © 2017年 LW. All rights reserved.
//

import UIKit
import CoreData

class CodataTool: NSObject {
  
  /*
   * 通过AppDelegate单利来获取管理的数据上下文对象，操作实际内容
   * 通过NSEntityDescription.insertNewObjectForEntityForName方法创建实体对象
   * 给实体对象赋值
   * 通过saveContext()保存实体对象
   */
  func SavaDataToCoredataWith(entity:String, dataDic:NSDictionary){
      do{
          //获取数据对象
          var myContext : NSManagedObjectContext!;
          if #available(iOS 10.0, *) {
              myContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
          } else {
              myContext = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
          }
          
          let inserInfo = NSEntityDescription.insertNewObject(forEntityName: entity, into: myContext);
          for (key, value) in dataDic {             // 遍历字典中的所有key value
              inserInfo.setValue(value, forKey: key as! String);
          }
          
          try myContext.save()
          
          print("保存数据成功")
          
      }catch{
          fatalError();
      }
  }
  
  /*
   查询数据
   */
  func getDataFromCoredataWith(entity:String , key:NSString)->Any{
      //获取数据对象
      var myContext : NSManagedObjectContext!;
      //声明数据的请求
      let request = NSFetchRequest<NSFetchRequestResult>(entityName: entity);
      if #available(iOS 10.0, *) {
          myContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
      } else {
          myContext = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
      }
      var requestData :Any?
      
      do{
          let dataList = try myContext.fetch(request) as! [NSManagedObject];
          
          for data in dataList as![Product] {
              
              if data.product_id == key.intValue{
                  requestData = data
                  return requestData as Any
              }else{
                  requestData = ""
              }
          }
      }catch{
          fatalError();
      }
      return requestData as Any
  }

  //清除coreData中的数据
  func deleteCoreDataWit(entity:String){
      //获取数据对象
      var myContext : NSManagedObjectContext!;
      //声明数据的请求
      let request = NSFetchRequest<NSFetchRequestResult>(entityName: entity);
      if #available(iOS 10.0, *) {
          myContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
      } else {
          myContext = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
      }

      do{
          let rels = try myContext.fetch(request) as! [NSManagedObject];
          for rel in rels{
              myContext.delete(rel);
          }
          try myContext.save();
          print("删除数据成功")
          
      }catch{
          fatalError();
      }
      
  }
  
  /**本地文件的读写*/
  func setProductNameData(){
      //取得txt文件路径
      let path = Bundle.main.path(forResource: "ProductName", ofType: "txt")!
      print (path)
      //设定路径
      let url: NSURL = NSURL(fileURLWithPath: path)
      
//        //定义可变数据变量
//        let data = NSMutableData()
//        //向数据对象中添加文本，并制定文字code
//        data.append("Hello Swift".data(using: String.Encoding.utf8, allowLossyConversion: true)!)
//        //用data写文件
//        data.write(toFile: url.path!, atomically: true)
      
      //从url里面读取数据，读取成功则赋予readData对象，读取失败则走else逻辑
      if let readData = NSData(contentsOfFile: url.path!) {
          //如果内容存在 则用readData创建文字列
//            print((data: readData as Data, encoding: String.Encoding.utf8.rawValue))
          let dataString:NSString = NSString.init(data: readData as Data, encoding: String.Encoding.utf8.rawValue) as Any as! NSString
          print(dataString)
          let array: [Any] = dataString.components(separatedBy: "\n")
         
          for index in 1...55{
              print(array[index-1])
              let dic:NSDictionary = ["name":array[index-1],"product_id":index]
              self.SavaDataToCoredataWith(entity: "Product", dataDic: dic)
          }
          
      } else {  
          //nil的话，输出空
          print("Null")
      }
  
  }

}

三、在AppDelegate.swift中关联CoreData

func applicationWillTerminate(_ application: UIApplication) {
        if #available(iOS 10.0, *) {
            self.saveContext()
        } else {
            // Fallback on earlier versions
        }
    }
    
    // MARK: - Core Data stack
    @available(iOS 10.0 , *)
    lazy var persistentContainer: NSPersistentContainer = {
       
        let container = NSPersistentContainer(name: "ProductCodata")
        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]
    }()
    
    lazy var managedObjectModel: NSManagedObjectModel = {
        let modelURL = Bundle.main.url(forResource: "ProductCodata", withExtension: "momd")!
        return NSManagedObjectModel(contentsOf: modelURL)!
    }()
    
    lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
        let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
        let url = self.applicationDocumentsDirectory.appendingPathComponent("ProductCodata.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
    }()
    
    // MARK: - Core Data Saving support
    @available(iOS 10.0 , *)
    func saveContext () {
        let context = persistentContainer.viewContext
        if context.hasChanges {
            do {
                try context.save()
            } catch {
                
                let nserror = error as NSError
                fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
            }
        }
    }

四、关于多表的关联

enter description here enter description here