GCD 队列串行 并行 同步 异步 小例
发现GCD Swift版有所更改，以后小例都用swift写，练习熟悉。
坚持，每天收获一点。
//
// ViewController.swift
// GCD_demo
//
// Created by apple on 2017/5/31.
// Copyright © 2017年 ZY. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
overridefunc viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
concurrentQueue()
}
overridefunc didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
//串行队列
//串行同步和异步的区别主要是：同步会阻塞线程，异步线程继续运行，耗时任务将被搁置执行
func serialQueueDemo(){
let serialQueue =DispatchQueue(label:"zy")//默认是串行队列
#if ture
for indexin 1..<10 {
serialQueue.async {//不管异步还是同步都只是开辟一个线程。
Thread.current.name? = "异步线程名字\(index)"
if index==3 || index==7 {
Thread.sleep(forTimeInterval: 5);//
}
print(serialQueue.label,index,Thread.current);
}
print("线程阻塞了吗")
}
#else
for indexin 1..<10 {
serialQueue.sync {//不管异步还是同步都只是开辟一个线程。
Thread.current.name? ="同步线程名字\(index)"
if index==3|| index==7 {
Thread.sleep(forTimeInterval:5);
}
print(serialQueue.label,index,Thread.current);
}
print("线程阻塞了吗")
}
#endif
}
//并发队列
func concurrentQueue(){
let concurrentQueyue =DispatchQueue(label: "zy.concurrent", attributes: DispatchQueue.Attributes.concurrent)
for indexin 1..<10 {
concurrentQueyue.async {//异步会动态开辟线程，耗时任务也会被异步执行，线程不会阻塞。
Thread.current.name? ="异步线程名字\(index)"
if index==3|| index==7 {
Thread.sleep(forTimeInterval:5);//
}
print(concurrentQueyue.label,index,Thread.current);
}
print("线程阻塞了吗")
}
for indexin 1..<10 {
concurrentQueyue.sync {//同步都只是开辟一个线程。会阻塞线程
Thread.current.name? ="同步线程名字\(index)"
if index==3|| index==7 {
Thread.sleep(forTimeInterval:5);
}
print(concurrentQueyue.label,index,Thread.current);
}
print("线程阻塞了吗")
}
}
}
小例参考：