pipe

题目描述 Farmer John always wants his cows to have enough water and thus has made a map of the N (1 <= N <= 700) water pipes on the farm that connect the well to the barn. He was surprised to find a wild mess of different size pipes connected in an apparently haphazard way. He wants to calculate the flow through the pipes. Two pipes connected in a row allow water flow that is the minimum of the values of the two pipe's flow values. The example of a pipe with flow capacity 5 connecting to a pipe of flow capacity 3 can be reduced logically to a single pipe of flow capacity 3: +---5---+---3---+ -> +-

题目描述 Farmer John always wants his cows to have enough water and thus has made a map of the N (1 <= N <= 700) water pipes on the farm that connect the well to the barn. He was surprised to find a wild mess of different size pipes connected in an apparently haphazard way. He wants to calculate the flow through the pipes. Two pipes connected in a row allow water flow that is the minimum of the values of the two pipe's flow values. The example of a pipe with flow capacity 5 connecting to a pipe of flow capacity 3 can be reduced logically to a single pipe of flow capacity 3: +---5---+---3---+ -> +-

Java NIO 管道是2个线程之间的单向数据连接。Pipe有一个source通道和一个sink通道。数据会被写到sink通道，从source通道读取。 @Test public void test1() throws IOException{ //1. 获取管道 Pipe pipe = Pipe.open(); //2. 将缓冲区中的数据写入管道 ByteBuffer buf = ByteBuffer.allocate(1024); Pipe.SinkChannel sinkChannel = pipe.sink(); buf.put("通过单向管道发送数据".getBytes()); buf.flip(); sinkChannel.write(buf); //3. 读取缓冲区中的数据 Pipe.SourceChannel sourceChannel = pipe.source(); buf.flip(); int len = sourceChannel.read(buf); System.out.println(new String(buf.array(), 0, len)); sourceChannel.close(); sinkChannel.close(); } 来源： CSDN 作者： 存在,及合理 链接： https://blog.csdn.net/qq

3. 与python交互 安装包 到 中文官网 查找客户端代码 联网安装 sudo pip install redis 使用源码安装 unzip redis-py-master.zip cd redis-py-master sudo python setup.py install 交互代码 引入模块 import redis 连接 try: r=redis.StrictRedis(host='localhost',port=6379) except Exception,e: print e.message 方式一：根据数据类型的不同，调用相应的方法，完成读写 更多方法同前面学的命令 r.set('name','hello') r.get('name') 方式二：pipline 缓冲多条命令，然后一次性执行，减少服务器-客户端之间TCP数据库包，从而提高效率 pipe = r.pipeline() pipe.set('name', 'world') pipe.get('name') pipe.execute() 封装 连接redis服务器部分是一致的 这里将string类型的读写进行封装 import redis class RedisHelper(object): def __init__(self, host='localhost', port=6379): self._

【进程间通信】 进程间由于空间独立，资源互相无法直接获取 此时在不同的进程间传递数据就需要专门的进程间通信方法 和磁盘交互： 使用中间文件，但是不安全，速度慢 进程间通信方法(IPC): 管道、消息队列、共享内存、信号、信号量、套接字 【管道通信Pipe】 1.原理: 在内存中开辟一块空间，形成管道结构，管道对多个进程可见，进程可以通过对管道的读写操作进行通信 2.[multiprocessing.Pipe] 1.fd1,fd2 = Pipe(duplex=True) 功能：创建一个管道 参数： duplex默认为True 表示双向管道 设置为False 表示单项管道 返回值： 返回两个管道流对象，表示管道两端 如果是双向管道，则都可以读写 如果是单向管道，则fd1只读　fd2只写 2.fd1.recv() 功能：从管道内读取信息 参数：无 返回值：读到的内容 注意：当管道内无内容的时候会阻塞 3.fd2.send(data) 功能：向管道写入内容 参数：要写的内容 注意：可以发送几乎python的任意数据类型 3.示例（双向管道）： from multiprocessing import Process,Pipe import os,time # 创建管道 fd1,fd2 = Pipe() def fun(name): time.sleep(3) # 向管道内写入内容 fd2