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Python全栈 Web(JavaScript 运算符、流程控制)

运算符: 赋值运算符:= 算术运算符:+ - * / % 自增自减:++ -- 自增自减在单独使用时放前放后没区别 如果参与其他运算时分前缀和后缀 ++ 在后 先使用后自增 ++ 在前 先自增后使用 关系运算符 >、 >=、 <、 <=、 ==、 != ===全等/恒等 !==不全等/不恒等 关系运算符的结果都为boolean类型 数字与字符串进行比较: 实现自动转换数据类型在比较 如果转换成功 按照数字比较 失败会变成NaN与数字比较 永远都是false 字符串之间的比较: 每个字符分别按照Unicode编码比较大小 如果当前字符相同进行后移 不相同直接出结果 == != 先进行数据转换后进行比较 只进行值得比较 === !== 直接进行数据比较 进行数据转换 同时判断数据类型和值是否完全相等 逻辑运算符: !非 对现有条件进行取反 非真

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线程的控制之守护线程_坦克大战帮助理解

后台线程 public final void setDaemon(boolean on) 将该线程标记为守护线程或用户线程 对象名.setDaemon(true); // 设置守护线程 当正在运行的线程都是守护线程时,Java虚拟机退出。该方法必须在启动线程前调用。 坦克大战帮助理解守护线程,如下图所示: 示例代码如下: 1 package cn.itcast_04; 2 3 /* 4 * 后台线程 5 * public final void setDaemon(boolean on) 将该线程标记为守护线程或用户线程。 6 * 当正在运行的线程都是守护线程时,Java虚拟机退出。 该方法必须在启动线程前调用。 7 * 8 * 帮助理解的守护线程的案例 9 * 游戏:坦克大战。 10 */ 11 public class ThreadDaemonDemo { 12 public static void main(String[] args) { 13 ThreadDaemon td1 = new ThreadDaemon(); 14 ThreadDaemon td2 = new ThreadDaemon(); 15 16 td1.setName("关羽"); 17 td2.setName("张飞"); 18 19 // 设置守护线程,在启动线程前 20 td1.setDaemon(true); 21 td2.setDaemon(true); 22 23 td1.start(); 24 td2.start(); 25 26 Thread.currentThread().setName("刘备"); 27 for (int x = 0; x < 5; x++) { 28 System.out.println(Thread.currentThread().getName() + ":" + x); 29 } 30 } 31 } 1 package cn.itcast_04; 2 3 public class ThreadDaemon extends Thread { 4 @Override 5 public void run() { 6 for (int x = 0; x < 100; x++) { 7 System.out.println(getName() + ":" + x); 8 } 9 } 10 } 程序运行的结果为: (一种运行情况) 刘备:0 刘备:1 刘备:2 刘备:3 刘备:4 张飞:0 张飞:1 张飞:2 张飞:3 张飞:4 张飞:5 张飞:6 张飞:7 张飞:8解释:刘备这个线程结束了(刘备阵亡了),关羽和张飞的线程也会立马结束,但是就算立马结束也需要一些时间缓冲!(即关羽和张飞抹脖子后也得抽搐几下才真正死了啊) 我的GitHub地址: https://github.com/heizemingjun 我的博客园地址: http://www.cnblogs.com/chenmingjun 我的蚂蚁笔记博客地址: http://blog.leanote.com/chenmingjun Copyright ©2018 黑泽明军 【转载文章务必保留出处和署名,谢谢!】

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openstack 调用API 实现云主机的IO 控制,CGroup 策略

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 # vim: tabstop= 4 shiftwidth= 4 softtabstop= 4 # Copyright (c) 2011 X.commerce, a business unit of eBay Inc. # Copyright 2010 United States Government as represented by the # Administrator of the National Aeronautics and Space Administration. # All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License" ); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http: //www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. # Single virtual machine io limit , reader 70 /MB , writer 50 /MB "" " curl -d '{"auth": {"tenantName": "admin", "passwordCredentials": {"username": "admin", "password": "admin"}}}' -H "Content-type: application/json" http: //127.0.0.1:35357/v2.0/tokens | python -m json.tool curl -v -d '{"ioctlAction": {"instance_name":"instance-0000000c","limit_reader":"40MB","limit_writer":"60MB"}}' -i http: //127.0.0.1:8774/v2/ba5a6a86a8224a70ba0ffde747d8a724/servers/e6b9cae7-8732-405d-9aaf-575643b4bbef/action -X POST -H "X-Auth-Project-Id: ba5a6a86a8224a70ba0ffde747d8a724" -H "Accept: application/json" -H "X-Auth-Token: 6f0c37595f384fd4a18766825cf49013" -H "Content-Type: application/json" "" " import time,sys,os,libvirt, trace back,re,subprocess,json from nova import log as logging from nova import flags from nova.periodic.blkio import config from nova import utils from nova.periodic.blkio import utils as blkio_utils FLAGS = flags.FLAGS LOG = logging.getLogger(__name__) class ActionIoctl(object): def __init__(self,instance_name,limit_reader,limit_writer): self.conn = libvirt.open(None) self.limitReader = int (limit_reader[ 0 :- 2 ]) self.limitWriter = int (limit_writer[ 0 :- 2 ]) self.name = instance_name self.path = FLAGS.instances_path def diskDeviceNum(self,disk): "" " Func info: Returns the number of hard disk,other is 8:0 " "" if disk == '/dev/sda1' or disk == '/dev/hda1' or disk[:- 1 ] == '/dev/sda' or disk[:- 1 ] == '/dev/hda' : return '8:0' elif disk == '/dev/sdb1' or disk == '/dev/hdb1' or disk[:- 1 ] == '/dev/sdb' or disk[:- 1 ] == '/dev/hdb' : return '8:16' elif disk == '/dev/sdc1' or disk == '/dev/hdc1' or disk[:- 1 ] == '/dev/sdc' or disk[:- 1 ] == '/dev/hdc' : return '8:32' elif disk == '/dev/sdd1' or disk == '/dev/hdd1' or disk[:- 1 ] == '/dev/sdd' or disk[:- 1 ] == '/dev/hdd' : return '8:48' else : return '8:16' def vmsPIDall(self): "" " Getting all vm port, return to " "" pid = list() try : cmds = "" "ps -ef |grep uuid|grep -v grep |awk '{print $2}'" "" pid=os.popen(cmds).readlines() return pid except Exception,e: LOG.error(_( '[-william-] Error %s' %e)) return def cgroupPath(self): '' ' Func info : Return Cgroup path ,Because the system is not the same, the Cgroup path is different also. By default , have RedHat, Centos, Ubuntu linux ... osType : The current system version , And return to ... Cpath : Cgroup path '' ' osType = open( '/etc/issue' ).readlines() for i in osType: if re.match( 'Ubuntu' ,i): Cpath = '/sys/fs/cgroup/' return Cpath elif re.match( 'CentOS' ,i): Cpath = '/cgroup/' return Cpath elif re.match( 'Red Hat' ,i): Cpath = '/cgroup/' return Cpath else : return '/sys/fs/cgroup/' def exeCmd(self,cmds): '' ' Perform system command ' '' LOG.info(_( 'exeCmd %s' %cmds)) try : exec_process = subprocess.Popen(cmds, stdin = subprocess.PIPE, stdout = subprocess.PIPE, stderr = subprocess.PIPE, shell = True) exec_process.wait() rest = exec_process.stdout.read() err = exec_process.stderr.read() if err == '' : return rest else : LOG.error(_( '[-william-] return values is null' )) except Exception,e: LOG.error(_( '[-william-] Error %s' ) %e) return '' ' Geting vmName name and pid ' '' def get_vm_pid(self,name): pid = self.conn.listDomainsID() try : pid = os.popen( "" "ps -ef |grep %s |grep -v grep |awk '{print $2}'" "" %name).readlines() return int (pid[ 0 ]) except: LOG.error(_( '[-william-] Error %s' \ % trace back.format_exc())) return def _vm_pids(self): try : return os.popen( 'pidof kvm' ).read().split() except: return def work(self): "" " Func info : working func ................ Cpath : is _Cpath function return values ... path : The current virtual machine IMG file path vm_count: All of the current node number of virtual machines size : Limit size mountInfo : mounting point "" " Cpath = self.cgroupPath() vm_pid = self.get_vm_pid(self.name) LOG.info(_( '[- william -] %s , %s' %(self.name,vm_pid))) r_size = self.limitReader * 1000 * 1000 w_size = self.limitWriter * 1000 * 1000 device = blkio_utils.instance_path(self.path) diskDeviceNum = self.diskDeviceNum(device) vmTaskPath = "%s/blkio/%s" %(Cpath,self.name) utils.execute( "mkdir" , "-p" ,vmTaskPath,run_as_root=True) utils.execute( "tee" , "%s/blkio.throttle.read_bps_device" %vmTaskPath,\ process_input = "%s %s" %(diskDeviceNum,r_size),\ run_as_root=True) utils.execute( "tee" , "%s/blkio.throttle.write_bps_device" %vmTaskPath, \ process_input = "%s %s" %(diskDeviceNum,w_size) ,\ run_as_root=True) LOG.info(_( "" " [-william-] echo '%s, %s, %s , %s , %s ' write oK " "" %(self.path , device, diskDeviceNum, w_size, r_size))) utils.execute( 'tee' , '%s/tasks' %vmTaskPath,\ process_input= str(vm_pid) ,\ run_as_root=True) LOG.info(_( '[- william-] append pid %s in task' %vm_pid)) if __name__ == "__main__" : sc = ActionIoctl( 'instance-0000000c' , '40MB' , '30MB' ) sc.work() 本文转自 swq499809608 51CTO博客,原文链接:http://blog.51cto.com/swq499809608/1412022

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Spring

Spring

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Rocky Linux

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Rocky Linux(中文名:洛基)是由Gregory Kurtzer于2020年12月发起的企业级Linux发行版,作为CentOS稳定版停止维护后与RHEL(Red Hat Enterprise Linux)完全兼容的开源替代方案,由社区拥有并管理,支持x86_64、aarch64等架构。其通过重新编译RHEL源代码提供长期稳定性,采用模块化包装和SELinux安全架构,默认包含GNOME桌面环境及XFS文件系统,支持十年生命周期更新。

WebStorm

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