aws fundamentals

"Web crawler Primer 02" HTTP Client library requests fundamentals and basic applicationsGuangdong Vocational and Technical College Aohaoyuan1. IntroductionThe first step in implementing a web crawler is to establish a network connection and initiate requests to network resources such as servers or Web pages. Urllib is currently the most common practice, but requests is more convenient than urlib, allowing people to access network resources in a simple

Linux Fundamentals:1, composed of small programs with a single purpose, the combination of small procedures to complete complex tasks;2, all documents;3, try to avoid capturing the user interface;4. Save the configuration file in plain text formatGUI interfaceGnomeKdeXfaceCLI interfaceBashCshZshKshTcshCommand prompt: Prompt#:root Administrator Prompt$: Normal user promptCommand format:Command optionsShort options:-Multiple options can be combined-a-b=

Linux Advanced Programming --BSD Socket of network programmingPurpose: The learning of technology is limited, the spirit of sharing is unlimited.a Fundamentals of network communicationTCP/IP Protocol Cluster Foundation: TCP/IP is a protocol cluster, because TCP-IP includes TCP, IPS, UDP, ICMP and many other protocols. Is the comparison between the OSI model and the TCP/IP model. TCP/IP divides the network into 4-tier models: The application layer, th

Linux System Fundamentals (ii)First, the Linux system structure1.Linux system structure is inverted tree type2./bin # #二进制可执行文件也就是系统命令/sbin # #系统管理命令存放位置/ Boot # #启动分区, responsible for system startup/ Dev # #设备管理文件/ etc # #大多数系统管理文件 /Home # #普通用户的家目录/lib # #32位系统库文件存放位置/lib64 # #64位系统库文件存放位置/media # #系统临时设备挂载点/mnt # #系统临时设备挂载点/run # #系统临时设备挂载点/opt # #第三方软件安装位置/proc # #系统信息/root # #超级用户家目录/srv,/var # #系统数据/sys # #系统管理, mostly about the kernel/ tmp # #系

Connect to a Java fundamentals---I/O technology (ii)Serialization and deserialization of Java objects What is called serialization and deserialization of objectsTo complete an object's input or output, you must also rely on the object output stream (ObjectOutputStream) and the object input stream (ObjectInputStream). The steps to output a serialized object using an object output stream are sometimes serialized, while the process of using an object inp

:not Found, the server could not find the requested Web page405:bad method, the server prohibits this request500: Server Internal Error2) Response header information, here are only a few common.Content-type: Specifies what type of data is returned.Set-cookie: Set a cookie to tell the browser to place this content in a cookie and request it next time.Content-encoding: Specifies the encoding of the response content.3) Response body: Usually the data that the server returns to us, such as the sourc

property and function of hidden objects, only public access is provided externally, encapsulation can improve security, reusability and so on.constructor functionThe constructor initializes the object with no specific return value, the return type, the function name and the class name.this keywordthisRepresents a reference to an object of this class.StaticUse static the modified member variable as a static variable;With a static decorated class, as a static class,Used to modify the method, it i

Source: https://www.scarydba.com/2017/06/20/database-fundamentals-3-whats-database/Grant FritcheyTranslation: Shesheni Liu Jongmao Xu Yali Lai HuifangPresidentIt is important to note that many people do not need to create their own databases. You may also not create your own tables or other data structures. You may also need to run backups, re-store and secure the operating system so that the application installs as you create the database. This is fu

Oracle- related Fundamentals relational database and non-relational database Relational database is a database based on the relational model, and the relational model is a two-dimensional table to represent and store the data;non-relational database (NoSQL) is a key-value pair that stores data in a way that Key-value . RedisDatabase and instance A database is a heap of files, a physical concept; a bunch of files inside a database file are loaded into

2017-2018-1 20155222 "Fundamentals of Information Security system Design" 10th week IPC mechanism under Linux The communication mechanism between multiple processes under Linux is called IPC (inter-process Communication), which is a way of communicating with each other across multiple processes. There are several ways of interprocess communication under Linux: Half-duplex pipes, Named pipes, message queues, signals, semaphores, shared memory,

Introduction: TitleImportJava.io.FileInputStream;ImportJava.io.FileOutputStream;/** * @authorCzchina **/ Public classTeststream { Public Static voidMain (string[] args) {FileInputStream FLs=NULL; FileOutputStream Fos=NULL; Try{FLS=NewFileInputStream ("E:/android/androidstudioprojects/text.txt"); FOS=NewFileOutputStream ("E:/android/androidstudioprojects/store.txt"); //generating a byte array byte[] buffer=New byte[500]; intnum = 0; intTMP = 0; intTMP1 = 0; for(inti=0;i) {tmp= Fls.rea

Introduction: Title ImportJava.io.FileInputStream;/** * @authorCzchina **/ Public classTeststream { Public Static voidMain (string[] args) {//TODO auto-generated Method Stub//declaring a reference to an input streamFileInputStream FLS =NULL; //declaring a reference to the output streamFileOutputStream fos =NULL; Try{ //first, generate an object representing the input streamFLS =NewFileInputStream ("E:/android/androidstudioprojects/text.txt"); //generating a byte array byte[

selector (Event- driven ) and the non-blocking feature of socket channel, it can effectively solve the situation that the high concurrency environment consumes a lot of thread resources for client request processing. (1) Traditional synchronous blocking IO (network socket programming socket): Each request for the client connection, need to allocate a separate thread for processing, because at any time to monitor whether it has data read and write, and in the data read and write operation, becau

Countdown shutdown command Tsshutdn ——-60-second Countdown shutdown command TOURSTART--XP profile (roaming XP programs that appear after installation is complete) taskmgr--– Task Manager EVENTVWR ——-Event Viewer Eudcedit ——-Character-font procedure Explorer ——-Open Resource Manager Packager ——-Object Wrapping Program perfmon.msc--Computer Performance Monitoring Program progman--– Program Manager regedit.exe--Registration Form Rsop.msc ——-Group Policy result set Regedt32

[One Moss per day]-Fundamentals of the Large Pool the following describes the 'large Pool 'introduced from Oracle 8 '. What is Large Pool ")? A large pool is an area in SGA similar to a shared pool, but its usage is strictly limited. Only a few types and sizes of memory can be allocated in this pool. The memory of the large pool is not from the shared pool, but directly from the SGA. Therefore, you need to increase the shared memory capacity when the

) { new Test02 (); T.test (); System.out.println (s);//Error }publicvoid Test () { System.out.println (s) ;}}unresolved compilation problem: static reference to the non-static field sIt is still reported that a static method cannot invoke a non-static variable.Although, the object of this class is initialized in a static method.The reason for the moment is unclear, Java, new an object and class static domain, is not in memory is not a place, have seen a video be

collections class cannot instantiate.Multithreading1, the difference between threads and processes4 states of a thread: run, ready, suspend, end.A process can have multiple threads, sharing the program's memory space between threads (code snippets, data, heap space, and some process-level resources, such as open files), but each thread has its own stack space.1) Use multithreading to reduce the response time of the program.2) threads are less expensive to create and switch than processes, makin

the upper layer into the packet segment to the lower layer. At the receiving end, the TCP protocol is responsible for reorganizing the received messages to the upper layer. The TCP protocol also handles end-to-end traffic control to avoid slow receivers not having enough buffers to receive large amounts of data sent by the sender. The UDP protocol is an unreliable, non-connected protocol .IP address: IP URL and IP host address. The IP URL represents the address of the network, and the IP host a

them in bulk and reclaim the memory at the right time (for example, by pressing the pause key or the level switch). Mono's memory recovery is done automatically in the background, and the system chooses the right time for garbage collection. At the right time, you can also manually call System.GC.Collect () to suggest that the system do a garbage collection.It is important to note that the call here is really just a suggestion, that the system may be recycled after a period of time, or it may b

; //newobj.i = this.i; //return NEWOBJ; //implementing Deep Replication-Mode 2: Serialization/deserializationBinaryFormatter BF =NewBinaryFormatter (); MemoryStream Ms=NewMemoryStream (); Bf. Serialize (MS, This); Ms. Position=0; returnBF. Deserialize (MS); } ...... } [Serializable] Public classA { Public stringMessage ="I am the original a"; }View Code PS: generally inheritable types should avoid implementing the ICloneable interface , because doing so would force a