Question

以下是Warning: StandardWrapperValve[LoginServlet]: Servlet.service() for servlet LoginServlet threw exception java.lang.NoClassDefFoundError: Could not initialize class org.apache.xml.security.Init at org.opensaml.DefaultBootstrap.initializeXMLSecurity(DefaultBootstrap.java:195) at org.opensaml.DefaultBootstrap.bootstrap(DefaultBootstrap.java:98) at opensamltest1.SAMLHelper.printSAMLObject(SAMLHelper.java:180) at LoginServlet.processRequest(LoginServlet.java:53) at LoginServlet.doPost(LoginServlet.java:100) at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283) at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167) at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206) at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180) at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235) at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119) at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283) at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200) at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132) at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111) at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77) at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536) at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112) at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117) at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56) at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137) at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591) at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571) at java.lang.Thread.run(Thread.java:745)中使用FetchedResultsController的示例，而另一个ViewController的保存未传递给它。

MainVC.swift
```
ViewController
```

AddRecordVC.swift

lazy var coreDataManager = CoreDataManager()

// Initialize fetched request
private var fetchRecordRequestController: NSFetchedResultsController = NSFetchedResultsController()

override func viewDidLoad() {
super.viewDidLoad()

// Do any additional setup after loading the view.

// Initialize managedObjectContext
let mainManagedObjectContext = coreDataManager.managedObjectContext

// Create Fetch Request
let fetchRequest = NSFetchRequest(entityName: "Record")

// Configure Fetch Request
fetchRequest.sortDescriptors = [NSSortDescriptor(key: "date", ascending: false)]

// Initialize Fetched Results Controller
fetchRecordRequestController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: mainManagedObjectContext, sectionNameKeyPath: nil, cacheName: nil)

// Configure Fetched Results Controller
fetchRecordRequestController.delegate = self

// Fetch data from object
do {
    try fetchRecordRequestController.performFetch()
} catch let fetchError as NSError {
    print("(RootViewController)fetchError: \(fetchError), \(fetchError.userInfo)")
}

// Add observer in NSNotificationCenter for NSManagedObjectContextObjectsDidChange
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(managedObjectContextObjectsDidChange), name: NSManagedObjectContextObjectsDidChangeNotification, object: mainManagedObjectContext)

override func viewWillDisappear(animated: Bool) {
NSNotificationCenter.defaultCenter().removeObserver(self)
}

// MARK: - NSFetchedResultsController Delegate Methods

func controllerWillChangeContent(controller: NSFetchedResultsController) {
    tableView.beginUpdates()
}

// Delete corresponding row in tableView
func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {
switch type {
case .Insert:
    tableView.insertRowsAtIndexPaths([newIndexPath!], withRowAnimation: .Fade)
case .Delete:
    tableView.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: .Fade)
case .Update:
    tableView.reloadRowsAtIndexPaths([indexPath!], withRowAnimation: .Fade)
case .Move:
    tableView.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: .Fade)
    tableView.insertRowsAtIndexPaths([newIndexPath!], withRowAnimation: .Fade)
}
}

func controllerDidChangeContent(controller: NSFetchedResultsController) {
tableView.endUpdates()
}

func managedObjectContextObjectsDidChange(notification: NSNotification) {

let mainManagedObjectContext = coreDataManager.managedObjectContext
guard let userInfo = notification.userInfo else { return }

if let inserts = userInfo[NSInsertedObjectsKey] as? Set<NSManagedObject> where inserts.count > 0 {
    print("--- INSERTS ---")
    print(inserts)
    print("+++++++++++++++")
    do {
        try mainManagedObjectContext.save()
    } catch let saveError as NSError {
        print("(RootViewController)saveError: \(saveError), \(saveError.userInfo)")
    }
}

if let updates = userInfo[NSUpdatedObjectsKey] as? Set<NSManagedObject> where updates.count > 0 {
    print("--- UPDATES ---")
    for update in updates {
        print(update.changedValues())
    }
    print("+++++++++++++++")
}

if let deletes = userInfo[NSDeletedObjectsKey] as? Set<NSManagedObject> where deletes.count > 0 {
    print("--- DELETES ---")
    print(deletes)
    print("+++++++++++++++")
}
}

一旦AddRuleVC回到RootVC，视图就不会刷新。 但是在应用程序退出并重新启动后，它确实显示了数据。 CoreDataStack使用了一个单独的类，如下所示。

CoreDataManager.swift

// Method to save the extracted values to CoreData Objects
private func saveValues() {
// Initializing
let mainManagedObjectContext = coreDataManager.managedObjectContext
// Initialize entity description
let RecordDescription = NSEntityDescription.entityForName("Record",inManagedObjectContext:mainManagedObjectContext)
let record = Record(entity: RecordDescription!, insertIntoManagedObjectContext: mainManagedObjectContext)
// Set object values from temporary variables
record.date = dateTemp!
record.tareWeight = tareWeightTemp
record.grossWeight = grossWeightTemp
record.nettWeight = nettWeightTemp
record.numberOfBags = numberOfBagsTemp
record.weightOfBags = weightOfBagsTemp
record.rivaju = rivajuTemp
record.putti = puttiTemp
record.rateOfPaddy = rateOfPaddyTemp
record.amount = amountTemp
// Save the object
do {
    if mainManagedObjectContext.hasChanges {
        try mainManagedObjectContext.save()
    }
} catch let saveError as NSError {
    print("(AddRecordViewController)saveError: \(saveError), \(saveError.userInfo)")
}
}

// MARK： - 助手方法

class CoreDataManager: NSObject {

// MARK: - Core Data Stack

lazy var managedObjectModel: NSManagedObjectModel = {
let modelURL = NSBundle.mainBundle().URLForResource("App Name", withExtension: "momd")!
return NSManagedObjectModel(contentsOfURL: modelURL)!
}()

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
// Create the coordinator and store
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite")
var failureReason = "There was an error creating or loading the application's saved data."
do {
    try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil)
} catch {
    // Report any error we got.
    var dict = [String: AnyObject]()
    dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
    dict[NSLocalizedFailureReasonErrorKey] = failureReason

    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
managedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
return managedObjectContext
}()

Answer 1

您的CoreDataManager类在AddRecordVC内生成一个新的托管对象上下文，与MainVC中的托管对象上下文不同，因此当您保存第二个上下文时，将更新持久性存储，但更改将赢得＆除非您合并更改，否则将反映在第一个上下文中。

这不好，你只需要一个主线程的上下文。所以你应该做的是使用依赖注入来管理对象上下文。在您的应用启动时启动CoreDataManager，然后将上下文注入MainVC，然后当您转到AddRecordVC时，也只是传递相同的上下文。

Answer 2

保存新项目后，您需要通过异步执行tableview.reloadData()重新加载表格视图。

虽然项目正在核心数据中保存，但在重新启动之前无法查看它们

2 个答案: