自己总结NSOperation

func loadWithUrlStr(urlStr:String){
    let queue = OperationQueue()
    
    
    
    print("111")
    let blockQueue1 = BlockOperation {
        for _ in 1 ..< 500000 {
            
        }
        
        print("blockQueue1%@",Thread.current)
    }
    let blockQueue2 = BlockOperation {
        for _ in 1 ..< 500000 {
            
        }
        print("blockQueue2%@",Thread.current)
    }
    
    let blockQueue3 = BlockOperation {
        for _ in 1 ..< 500000 {
            
        }
        print("blockQueue3%@",Thread.current)
    }
    let blockQueue4 = BlockOperation {
        for _ in 1 ..< 500000 {
            
        }
        print("blockQueue4%@",Thread.current)
    }
    let blockQueue5 = BlockOperation {
        for _ in 1 ..< 500000 {
            
        }
        print("blockQueue5%@",Thread.current)
    }
    let blockQueue6 = BlockOperation {
        for _ in 1 ..< 500000 {
            
        }
        print("blockQueue6%@",Thread.current)
    }
    
    let blockQueue7 = BlockOperation {
        for _ in 1 ..< 500000 {
            
        }
        print("blockQueue7%@",Thread.current)
    }
    let blockQueue8 = BlockOperation {
        for _ in 1 ..< 500000 {
            
        }
        print("blockQueue8%@",Thread.current)
    }
    print("2222")
    blockQueue7.addDependency(blockQueue5)
    blockQueue5.addDependency(blockQueue2)

    blockQueue2.queuePriority = .high
    blockQueue5.queuePriority = .high
    blockQueue7.queuePriority = .veryHigh

    queue.addOperations([blockQueue1,blockQueue2,blockQueue3,blockQueue4,blockQueue5,blockQueue6,blockQueue7,blockQueue8], waitUntilFinished: true)
    // 注意一点，添加了依赖关系的会被放到后面执行。
    // 没有依赖和优先级：执行的顺序不确定
    // 只有依赖：执行的顺序不确定，有依赖的那个最后执行,只能确定依赖的先后顺序，不能确定其他的顺序
    // 只有优先级：执行优先级高的，其他顺序不确定
    // 有依赖和优先级：先执行依赖，然后执行优先级
    
}