common knowledge book

One, theFS (file system) file Operationvar fs=require ("FS") A, create the file, and write the data Fs.writefile ("Demo.txt", "hello,world!", function (Err,data) { if (err) Console.log (ERR) Console.log ("Create File Success")})b Rename the file or move the fileFs.rename ("Demo.txt", "Demo1.txt", function (Err) {Rename the Demo.txt to Demo1.txt if (err) console.log (err); Console.log ("Rename Success")})Fs.rename ("Demo.txt", "Demo/demo.txt", function (Err) {Move the Demo.txt to the

gesturesUipangesturerecognizer *pan = [[Uipangesturerecognizer alloc] Initwithtarget: Self action:@selector (panaction:)];[ImageView Addgesturerecognizer:pan];[self. View Addsubview:imageview];}Drag events for panning gestures-(void) Panaction: (Uipangesturerecognizer *) pan{Cgpoint point=[pan Translationinview:self. view];Pan.view.center=cgpointmake (Pan.view.center.x+point.x, PAN.VIEW.CENTER.Y+POINT.Y);[Pan Settranslation:cgpointzero InView:self. view];}11. Pictures can respond to events, suc

=" +val.value; Parameters passed into the background Ajaxrequest (Url,data,responsecustomer); //Real Ajax functions to invoke } Second, the implementation of Jquery Ajax[JavaScript]View Plaincopy function Getwhmans (obj) { var url="Bbtj.do?method=getwhman"; URL to request background $ ("#whman"). empty (); //Pre-empty $ ("#whman"). Append ($ (' Plus--Please select--Options if ($ (obj). val () = ="") Return //No value, return url+="areaid=" +$ (obj). val (); URL P

First, the three main characteristics of object-oriented reply: encapsulation: Masking internal details, calling external interface to implement corresponding function (function call) Inheritance: Subclass inherits attributes and methods in parent class polymorphism (no polymorphic concept in JS) Ii. inheritance suggestion reply: Inherit: Subclass inherits properties and methods from parent class, these properties and methods do not need to implement the kind of process inheritance in subclasses

1. Get the Project path: Request.getcontextpath ();2. Get the requested parameter: Request.getquerystring ();3. Specify the character encoding format for the request: Urlencoder.encode (text, "UTF-8");Configure the servlet parameter in 4.web.xml,To read this parameter in the servlet, override the Init method5.${} represents a JSP built-in object6.7.java.lang.threadlocal.get () method returns the value in the current thread copy of this thread's local variable8. Determine if a string array contai

; top:0; Bottom; Opacity:1 background-color: #111;} This way, when you bring a search box to the top of some browsers, swiping down will quickly appear blank (the height of the search box at the top of the browser) all high highs can solve these bugs25.meta Label1.13.data URI scheme is defined in the RFC2397The data URI scheme is defined in RFC2397 to embed some small data directly into a Web page, eliminating the need to load it from an external file. Currently, the data URI scheme

determine when the method is called.(5) Equals methodUsed to compare the equality of two objects(6) Hashcode methodFor hash lookups, overriding the Equals method generally overrides the Hashcode method.(7) Wait methodCauses the current thread to wait for the lock on the object, and the current thread must be the owner of the object, which is the lock that owns the object. The wait () method waits until the lock is acquired or interrupted.(8) Notify methodWakes a thread waiting on the object.(9)

password usage timeB: Password optimization: Through the Pam_crack module to set the password complexity requirements, record the number of historical password; Set user lock policy through Pam_tally24. Historical order1) History # #查看历史命令History–w # #将历史命令写入到文件中History–c # #清除内存中历史命令Use history command: Up button,!! Part of the history commandBy default: History commands are recorded in the/.bash_history file, only2) The history command is written to the file when exiting or using "history-w"3

modifying the CREATESTRUCT CS Cs.style = ~ (LONG) fws_addtotitle;if (! CMDIChildWndEx::P Recreatewindow (CS)) return False;return TRUE;}void Cscale3dcscaleweightview::oninitialupdate () {cformview::oninitialupdate (); CMDIChildWndEx * pframe = (cmdichildwndex*) this->getparentframe ();Cscale3dcchildframe * Pmidframe = (cscale3dcchildframe*) pframe;pmidframe->setwindowtext (_T ("Weighing data area"));//TODO: Add private code here and/or call base class}6. Change the background color of the viewB

configuration when all users log on/etc/login.defsAdditional parameter settings for kernel modules/etc/modprobe.confLog settings file/etc/syslog.confLog file/varVarious logs/var/logMajor system logs/var/log/messageSystem login log ssh POP3 telnet ftp/var/log/secureLogin information/var/log/wtmpViewLast-10Scheduled Tasks/var/spool/var/spool/cronSystem User mail Storage directory/var/spool/mailTemporary Mail directory/var/spool/clientmqueueMapping of virtual directory memory/procKernel version/pr

UTF8 and Unicode (International GB) GBK (Chinese translation)Text Programmer: Edit text into ASCLLNano Text Editor Nano Yue Create file name Yue and can edit text inside (press Ctrl+x to exit input y save =ctrl+o Input n Direct exit Ctrl + C cancel return)File detection file type Yue (display UTF8) detection yue file is UTF8RM Delete a file or directoryCP Copy (default copy file if copy directory is required to add-R) CP source file Destination fileClear clears the Command window recordLinux

1, MyBatis ID write-back: There is a business in the development process, the business object itself is a table, business object extension information is another table, here in the new when the business object table to insert a piece of data, and then the Business Object Extension table to insert the extension information, which is used here ID write-Back in MybaitisLiezi:Session.insert ("mm.xxx", map);//Insert business object information corresponding SqlSummary of

1. The constant representation of each type in JS: Number:number string:string Object:objec2. Use of the TypeOf operator in JS: Used to determine what type an object is, and the return value is a string (the string form of constants of various types)var message = "some string";Alert ((typeof message) = = String){Alert ("OK");}--Result: false, OKAlert (typeof message = = "string"); -true3, typeof can not accurately represent the type of the class (for example, the following example: Method studen

basis of Common machine learning Data mining knowledge points SSE (Sum of squared error, squared error and) SSE=∑I=1N (Xi−x⎯⎯⎯) 2 sse=\sum_{i=1}^{n} (x_i-\overline{x}) ^2 SAE (sum of Absolute error, absolute error and) sae=∑i=1n| xi−x⎯⎯⎯| sae=\sum_{i=1}^{n}| x_i-\overline{x}| SRE (Sum of Relative error, relative error and) Sre=∑i=1nxi−x⎯⎯⎯x⎯⎯⎯sre=\sum_{i=1}^{n}{\frac{x_i-\overline{x}}{\overline{x}}} MSE (M

;# Delete: syntax: ALTER TABLE tablename drop column colummname;ALTER TABLE pet drop column des;To rename a table:Syntax: Rename table tablename1 to tablename2;Rename table pet to animals;Add ID FieldYou can do the following:# add ID field, including primary keyALTER TABLE pet Add ID int not NULL primary key auto_increment first;To set the index:to set a foreign key, in the reference table (referencing table, i.e. Pc tables ) and referenced tables (referencedtable, i.e. parts tables ) , the corr

Label:1. When using the set in (X,x ... The parameters can be single or multiple when they are single: Findbyids (list Select From Jria where ID inOpen= "(" separator= "," close= ")" >#{item} collection= "Array" when an array is set 2 When there are multiple parameters for a query, such as Findbyids (String name, long[] IDs) This situation requires special attention, when passing parameters, be sure to use the map mode, so that the collection property can specify the name Here is an example map

set to True, the cache will be emptied every time the statement is called. The SELECT statement is set to False by default True/false False UseCache If set to true, the result set of the statement is cached. The SELECT statement is set to False by default True/false False Timeout Sets the maximum time that a drive waits for a response before throwing an exception, with no value set by default and determined by the drive itself Posit

Nls_lang format:Nls_lang = Language_territory.charsetThere are three components (language, geography, and character set), each of which controls the characteristics of the NLS subset. whichlanguage specifies the language of the server message.territory specifies the date and number format for the server.CharSet specifying a character setFor example:American_america. Us7sciiAMERICAN _ AMERICA. Zhs16gbkOnly language information is displayed because the locale and character set of the OS are used b

People who have played Linux will know that there are really a lot of commands in Linux, but people who have played Linux have never bothered by the fact that Linux commands are so many, because we only need to master the commands we use most often. Of course you can also use to find the man, he will help you solve a lot of problems. However, everyone's purpose of playing Linux is different, so the commands they often use are very big, and I mainly use Linux for C + + and shell programs, so

-only mode (host-only)In this mode, the VMware virtual machine communicates with the host via the fake Nic VMnet1, but the virtual machine and the real network are isolated.4. Linux Management ToolsThere are many remote management tools available in Linux, and the following are some of the tools used in learning.(1) SecureCRTSECURECRT can be implemented under Windows to the UNIX or Linux server host, only need to simply configure. Specific configuration and use of the method, you can refer to: 7