多线程网络02

作者: 努力爬行中的蜗牛 | 来源:发表于2019-12-11 19:45 被阅读0次

1 GCD栅栏函数

栅栏函数用户控制队列里异步函数的的执行顺序。
注：栅栏函数不能使用全局并发队列，需要用自己创建的并发队列。

- (void)barrier {
    // 创建并发队列
    dispatch_queue_t queue = dispatch_queue_create("com.zyx.barrier", 0);
    // 创建人物，添加到队列
    dispatch_async(queue, ^{
        NSLog(@"download1-----");
    });
    dispatch_async(queue, ^{
        NSLog(@"download2-----");
    });
    // 栅栏函数，用于控制先执行人物1和2 再执行任务3
    dispatch_barrier_async(queue, ^{
        NSLog(@"++++++++++++++++++++++");
    });
    dispatch_async(queue, ^{
        NSLog(@"download3-----");
    });
}

2 GCD快速迭代

开子线程和主线程一起完成遍历任务，任务的执行是并发的。

- (void)applyDemo {
    /*
     参数1：遍历次数
     参数2：队列（并发队列）
     参数3：索引
     */
    dispatch_apply(20, dispatch_get_global_queue(0, 0), ^(size_t index) {
        NSLog(@"%zd---%@",index,[NSThread currentThread]);
    });
}

// 文件剪切操作
- (void)moveFile {
    // 1 拿到要移动文件路径
    NSString *from = @"/Users/apple/Desktop/from";
    // 2 获取目标文件路径
    NSString *to = @"/Users/apple/Desktop/to";
    // 3 得到目录下所有文件
    NSArray *filePath = [[NSFileManager defaultManager] subpathsAtPath:from];
    NSLog(@"%@",filePath);
    // 4 移动文件到指定目录
    NSInteger count = filePath.count;
    dispatch_apply(count, dispatch_get_global_queue(0, 0), ^(size_t index) {
        // 4.1 拼接文件全路径
        NSString *fullPath = [from stringByAppendingPathComponent:filePath[index]];
        NSString *toFullPath = [to stringByAppendingPathComponent:filePath[index]];
        NSError *error;
        [[NSFileManager defaultManager] moveItemAtPath:fullPath toPath:toFullPath error:&error];
    });
}

3 GCD队列组的使用

// 队列组
- (void)group1 {
    dispatch_queue_t queue = dispatch_get_global_queue(0, 0);
    dispatch_group_t group = dispatch_group_create();
    dispatch_group_async(group, queue, ^{
        NSLog(@"download1-----");
    });
    dispatch_group_async(group, queue, ^{
        NSLog(@"download2-----");
    });
    dispatch_group_async(group, queue, ^{
        NSLog(@"download3-----");
    });
    // 拦截通知，当当队列里面的任务执行完毕后进入该方法，该方法不会阻塞
    dispatch_group_notify(group, queue, ^{
        NSLog(@"task is over");
    });
    
    // 该方法是阻塞的
    dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
    NSLog(@"---end---");
    
}

- (void)group2 {
    dispatch_queue_t queue = dispatch_get_global_queue(0, 0);
    dispatch_group_t group = dispatch_group_create();
    // 该方法后面的异步任务会被纳入到队列组的监听范围中
    dispatch_group_enter(group);
    dispatch_group_async(group, queue, ^{
        NSLog(@"download1-----");
        dispatch_group_leave(group);
    });
    
    dispatch_group_enter(group);
    dispatch_group_async(group, queue, ^{
        NSLog(@"download2-----");
        dispatch_group_leave(group);
    });
    
    dispatch_group_enter(group);
    dispatch_group_async(group, queue, ^{
        NSLog(@"download3-----");
        dispatch_group_leave(group);
    });
    // 拦截通知，当当队列里面的任务执行完毕后进入该方法
    dispatch_group_notify(group, queue, ^{
        NSLog(@"task is over");
    });
}

4 GCD异步函数方式2

- (void)asyncConcurrent {
    /*
     参数1：队列
     参数2：参数3函数的参数
     参数3：函数，用于封装任务
     */
    dispatch_async_f(dispatch_get_global_queue(0, 0), NULL, task);
    dispatch_async_f(dispatch_get_global_queue(0, 0), NULL, task);
    dispatch_async_f(dispatch_get_global_queue(0, 0), NULL, task);
}

void (task)(void *params) {
    NSLog(@"--%s--",__func__);
}

5 单例模式通用宏

#define SingleH(name) + (instancetype)share##name;

#if __has_feature(objc_arc) // ARC模式
#define SinglM(name) static id _instance;\
+ (instancetype)allocWithZone:(struct _NSZone *)zone { \
    static dispatch_once_t onceToken; \
    dispatch_once(&onceToken, ^{ \
        _instance = [super allocWithZone:zone]; \
    }); \
    return _instance; \
} \
\
+ (instancetype)share##name { \
    return [[self alloc] init]; \
} \
\
- (id)copyWithZone:(NSZone *)zone { \
    return _instance; \
} \
\
- (id)mutableCopyWithZone:(NSZone *)zone { \
    return _instance; \
} 
#else // MRC模式
#define SinglM(name) static id _instance;\
+ (instancetype)allocWithZone:(struct _NSZone *)zone { \
    static dispatch_once_t onceToken; \
    dispatch_once(&onceToken, ^{ \
        _instance = [super allocWithZone:zone]; \
    }); \
    return _instance; \
} \
\
+ (instancetype)share##name { \
    return [[self alloc] init]; \
} \
\
- (id)copyWithZone:(NSZone *)zone { \
    return _instance; \
} \
\
- (id)mutableCopyWithZone:(NSZone *)zone { \
    return _instance; \
} \
- (oneway void)release { \
    \
} \
\
- (instancetype)retain { \
    return _instance; \
} \
\
- (NSUInteger)retainCount { \
    return MAXFLOAT; \
}
#endif

6 NSOperation基本概念

6.1 简介

NSOperation的作用
配合使用NSOperation和NSOperationQueue也能实现多线程编程
NSOperation和NSOperationQueue实现多线程的具体步骤
1）先将需要执行的操作封装到一个NSOperation对象中
2）然后将NSOperation对象添加到NSOperationQueue中
3）系统会自动将NSOperationQueue中的NSOperation取出来
4）将取出的NSOperation封装的操作放到一条新的线程中执行

6.2 NSOperation的子类

NSOperation是个抽象类，并不具备封装操作的能力，必须要使用它的子类
使用NSOperation紫烈的方式有3种
1）NSInvocationOperation
2）NSBlockOperation
3）自定义子类集成NSOperation，实现内部相应的方法

- (void)invocationOperation { // 不会开启新的线程
    /*
     参数1：目标对象
     参数2：执行的操作方法
     参数3：方法的参数
     */
    NSInvocationOperation *op1 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(download1) object:nil];
    [op1 start];
    
    NSInvocationOperation *op2 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(download1) object:nil];
    [op2 start];
    
    
    NSInvocationOperation *op3 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(download1) object:nil];
    [op3 start];
}

- (void)download1 {
    NSLog(@"%s--%@",__func__,[NSThread currentThread]);
}

- (void)blockOperation {
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1--%@",[NSThread currentThread]);
    }];
    [op1 start];
    
    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1--%@",[NSThread currentThread]);
    }];
    [op2 start];
    
    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1--%@",[NSThread currentThread]);
    }];
    
    NSBlockOperation *op4 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1--%@",[NSThread currentThread]);
    }];
    [op4 start];
    
    NSBlockOperation *op5 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1--%@",[NSThread currentThread]);
    }];
    [op5 start];
    
    NSBlockOperation *op6 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1--%@",[NSThread currentThread]);
    }];
    [op6 start];
    
    // 如果block操作里面的任务超过1个，那么会开启多个线程，但不一定是子线程
    [op3 addExecutionBlock:^{
        NSLog(@"4--%@",[NSThread currentThread]);
    }];
    
    [op3 addExecutionBlock:^{
        NSLog(@"5--%@",[NSThread currentThread]);
    }];
    
    [op3 addExecutionBlock:^{
        NSLog(@"6--%@",[NSThread currentThread]);
    }];
    
    [op3 start];
}

7 NSOperationQueue的基本使用

- (void)blockOperationWithQueue {
    // 1 创建操作
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1--%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"2--%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"3--%@",[NSThread currentThread]);
    }];
    
    // 2 创建队列
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    
    // 3 将操作添加到队列
    [queue addOperation:op1];
    [queue addOperation:op2];
    [queue addOperation:op3];
    
    // 简便方法
    [queue addOperationWithBlock:^{
        NSLog(@"4--%@",[NSThread currentThread]);
    }];
}

- (void)invocationOperationWithQueue {
    // 1 创建操作
    NSInvocationOperation *op1 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(download1) object:nil];
    NSInvocationOperation *op2 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(download1) object:nil];
    NSInvocationOperation *op3 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(download1) object:nil];
    
    // 2 创建队列
    /*
     NSOperationQueue
     主队列：和GCD主队列一样，也是串行队列 [NSOperationQueue mainQueue]
     非主队列：[[NSOperationQueue alloc] init]
     非主队列非常特殊，又分为串行队列和并发队列，默认是并发队列
     */
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    
    // 3 添加操作到队列中执行
    [queue addOperation:op1]; // 内部已经调用的start方法
    [queue addOperation:op2];
    [queue addOperation:op3];
}

8 自定义NSOperation

- (void)customOperationWithQueue {
    // 创建操作
    ZYXOperation *op1 = [[ZYXOperation alloc] init];
    // 创建队列
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    // 添加操作到队列
    [queue addOperation:op1];
}

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface ZYXOperation : NSOperation

@end

NS_ASSUME_NONNULL_END

#import "ZYXOperation.h"

@implementation ZYXOperation
- (void)main { // 自定义操作需要实现该方法，明确要执行什么操作
    NSLog(@"main---%@",[NSThread currentThread]);
}
@end

9 NSOperation的其他用法

9.1 如何设置串行队列

- (void)test {
    // 1 创建队列
    NSOperationQueue *queue = [[NSOperationQueue alloc] init]; // 默认是并发队列
    // maxConcurrentOperationCount 最大执行并发操作数量
    // maxConcurrentOperationCount默认值为-1 表示不受限制
    // maxConcurrentOperationCount = 0 不会执行操作
    // maxConcurrentOperationCount = 1 串行队列
    // maxConcurrentOperationCount >= 2 并发队列
    queue.maxConcurrentOperationCount = 1;
    // 2 创建操作
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1--%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"2--%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"3--%@",[NSThread currentThread]);
    }];
    // 添加操作到队列
    [queue addOperation:op1];
    [queue addOperation:op2];
    [queue addOperation:op3];
}

9.2 队列任务的开始、暂停、继续以及取消操作

- (IBAction)startOperation:(UIButton *)sender {
    [self test];
}

// 暂停任务
- (IBAction)pauseOperation:(UIButton *)sender {
    // 暂停是可以恢复的
    // 队列中的任务也是有状态的：已执行、正在执行、未执行
    // 不能取消队列里面正在执行的任务
    [self.queue setSuspended:YES];
}

// 继续任务
- (IBAction)restartOperation:(UIButton *)sender {
    [self.queue setSuspended:NO];
}

// 取消任务
- (IBAction)cancelOperation:(UIButton *)sender {
    // 取消是不可以恢复的
    [self.queue cancelAllOperations];
}

- (void)test {
    // 1 创建队列
    self.queue = [[NSOperationQueue alloc] init]; // 默认是并发队列
    // maxConcurrentOperationCount 最大执行并发操作数量
    // maxConcurrentOperationCount默认值为-1 表示不受限制
    // maxConcurrentOperationCount = 0 不会执行操作
    // maxConcurrentOperationCount = 1 串行队列
    // maxConcurrentOperationCount >= 2 并发队列
    self.queue.maxConcurrentOperationCount = 1;
    // 2 创建操作
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        for (int i = 0; i < 10000; i++) {
            NSLog(@"1--%d--%@",i,[NSThread currentThread]);
        }
    }];
    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        for (int i = 0; i < 10000; i++) {
            NSLog(@"2--%d--%@",i,[NSThread currentThread]);
        }
    }];
    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        for (int i = 0; i < 10000; i++) {
            NSLog(@"3--%d--%@",i,[NSThread currentThread]);
        }
    }];
    // 添加操作到队列
    [self.queue addOperation:op1];
    [self.queue addOperation:op2];
    [self.queue addOperation:op3];
}

9.3 自定义NSOperation的取消操作

- (IBAction)startOperation:(UIButton *)sender {
    // 1 创建自定义操作
    ZYXOperation *op1 = [[ZYXOperation alloc] init];
    // 2 创建队列
    self.queue = [[NSOperationQueue alloc] init];
    // 3 添加操作到队列
    [self.queue addOperation:op1];
}

// 暂停任务
- (IBAction)pauseOperation:(UIButton *)sender {
    // 暂停是可以恢复的
    // 队列中的任务也是有状态的：已执行、正在执行、未执行
    // 不能取消队列里面正在执行的任务
    [self.queue setSuspended:YES];
}

// 继续任务
- (IBAction)restartOperation:(UIButton *)sender {
    [self.queue setSuspended:NO];
}

// 取消任务
- (IBAction)cancelOperation:(UIButton *)sender {
    // 取消是不可以恢复的
    [self.queue cancelAllOperations];
}

- (void)main {
    for (int i = 0; i < 10000; i++) {
        NSLog(@"1--%d---%@",i,[NSThread currentThread]);
    }
    
    // 官方推荐方式，也可以放在循环里面，但这样会消耗性能
    if (self.isCancelled) {
        return;
    }
    
    for (int i = 0; i < 10000; i++) {
        NSLog(@"2--%d---%@",i,[NSThread currentThread]);
    }
    
    if (self.isCancelled) {
        return;
    }
    
    for (int i = 0; i < 10000; i++) {
        NSLog(@"3--%d---%@",i,[NSThread currentThread]);
    }
}

10 NSOperation操作依赖和监听

10.1 操作依赖和监听

- (void)operationDepency {
    // 1 创建队列
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    NSOperationQueue *queue2 = [[NSOperationQueue alloc] init];
    // 2 创建操作
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1--%@",[NSThread currentThread]);
    }];
    
    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
         NSLog(@"2--%@",[NSThread currentThread]);
    }];
    
    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
         NSLog(@"3--%@",[NSThread currentThread]);
    }];
    
    
    // 操作依赖
    op3.completionBlock = ^{
        NSLog(@"task is over--%@",[NSThread currentThread]);
    };
    // 添加操作依赖  不仅同一个队列可以，而且不同队列之间亦可以
    // 注意：不能添加循环依赖，这样会导致不会执行任何操作 依赖可以跨队列
    [op1 addDependency:op2];
    [op2 addDependency:op3];
    
    // 添加操作到队列
    [queue addOperation:op1];
    [queue addOperation:op2];
    [queue2 addOperation:op3];
}

11 NSOperation实现线程间通信

11.1 下载图片demo

- (void)downloadImage {
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        NSString *str = @"http://cdn.duitang.com/uploads/item/201504/19/20150419H4413_XdNfU.thumb.700_0.png";
        NSURL *url = [NSURL URLWithString:str];
        NSData *data = [[NSData alloc] initWithContentsOfURL:url];
        UIImage *image = [UIImage imageWithData:data];
        //更新UI
        [[NSOperationQueue mainQueue] addOperationWithBlock:^{
            self.imageView.image = image;
        }];
    }];
    [queue addOperation:op1];
}

11.2 下载并合成图片

- (void)downloadCombineImage {
    // 创建队列
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    
    __block UIImage *image1;
    __block UIImage *image2;
    // 下载图片1
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        NSString *str = @"http://cdn.duitang.com/uploads/item/201504/19/20150419H4413_XdNfU.thumb.700_0.png";
        NSURL *url = [NSURL URLWithString:str];
        NSData *data = [[NSData alloc] initWithContentsOfURL:url];
        image1 = [UIImage imageWithData:data];
    }];
    
    // 下载图片2
    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        NSString *str = @"http://5b0988e595225.cdn.sohucs.com/images/20171210/362dcd1c009842ff99b33f5d51bbfb80.jpeg";
        NSURL *url = [NSURL URLWithString:str];
        NSData *data = [[NSData alloc] initWithContentsOfURL:url];
        image2 = [UIImage imageWithData:data];
        
    }];
    
    // 合成图片
    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        // 获取上下文
        UIGraphicsBeginImageContext(CGSizeMake(200, 200));
        // 画image1
        [image1 drawInRect:CGRectMake(0, 0, 100, 200)];
        // 画image2
        [image2 drawInRect:CGRectMake(100, 0, 100, 200)];
        // 获取图片
        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
        // 关闭上下文
        UIGraphicsEndImageContext();
        //更新UI
        [[NSOperationQueue mainQueue] addOperationWithBlock:^{
            self.imageView.image = image;
        }];
    }];
    
    // 添加依赖
    [op3 addDependency:op1];
    [op3 addDependency:op2];
    
    // 添加操作到队列
    [queue addOperation:op1];
    [queue addOperation:op2];
    [queue addOperation:op3];
}

12 多线程补充

12.1 在使用NSOperation和NSOperationQueue时，将操作添加到队列时，会自动条用operation的start方法。而在调用start方法时，会去调用main方法。
12.2 在使用NSThread时，初始化时，可以直接使用init进行初始化，然后再其main方法里面添加任务。

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [self customThread2];
}

- (void)customThread {
    ZYXOperation *op1 = [[ZYXOperation alloc] init];
    NSOperationQueue *queue = [[NSOperationQueue alloc] init];
    [queue addOperation:op1];
}

- (void)customThread2 {
    ZYXThread *op1 = [[ZYXThread alloc] init];
    [op1 start];
}

#import "ZYXOperation.h"

@implementation ZYXOperation
- (void)start {
    NSLog(@"start--start");
    [super start];
    NSLog(@"start--end");
}

- (void)main {
    NSLog(@"main--start");
    [super main];
    NSLog(@"main--end");
}
@end

#import "ZYXThread.h"

@implementation ZYXThread
- (void)main {
    NSLog(@"%s---%@",__func__,[NSThread currentThread]);
}
@end

多线程网络02

1 GCD栅栏函数

2 GCD快速迭代

3 GCD队列组的使用

4 GCD异步函数方式2

5 单例模式通用宏

6 NSOperation基本概念

7 NSOperationQueue的基本使用

8 自定义NSOperation

9 NSOperation的其他用法

10 NSOperation操作依赖和监听

11 NSOperation实现线程间通信

12 多线程补充

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