difference between ndf and forward

_ New _ init _ difference, __new ___ init _ difference 1 class A(object):2 def __init__(self,*args, **kwargs):3 print "init A"4 def __new__(cls,*args, **kwargs):5 print "new A %s"%cls6 　　　　 #return super(A, cls).__new__(cls, *args, **kwargs)7 return object.__new__(cls, *args, **kwargs) Description 1. Only new classes inherited from objects have _ new __ 2. _ new _ must have a

Other" is: "+two.down); + -System.out.println ("Tixing's Down is:" +tixing.down); + } A}View Code Instance methods and class methods access to instance variables and class variablesAn instance method can manipulate instance variables of the current object, or it can manipulate class variables. An instance method is called by an instance object. Class methods cannot access instance variables, only class variables. A class method is called by a class name or an instance object.

Difference between http Get and Post, difference between getpost1. Get is a request to request data from the server, and Post is a request to submit data to the server;2. get is to add the parameter data queue to the URL referred to by the action attribute of the submission form. The values correspond to each field in the form one by one and can be seen in the address bar. Post is implemented through the HT

Lazy loading is the default way of associating objects in Hibernate, and lazy loading will first query the object and get the object's ID.SQL statements are actually written when they are actually being used for data.Lazy loading is a valid load period when the session is opened, so we must keep the session open when we want to use lazy loading.Urgent loading is the direct use of SQL statements to access the database, but speed relative to lazy loading faster.The Get () method emits an SQL state

* Lazy loading when loading an entity, it is not immediately loaded from the database, that is, loaded into memory from the database. When loading an entity, the load is immediately queried from the database, and the class associated with it is queried at the same time.The rush load will be quick, because it has been loaded for us at the first load. Lazy loading is relatively slow, because it does not perform SQL operations until we need to query the door.The advantage of lazy loading is that th

) nsarray *2.weak: Various UI controls (but not absolute, there are controls to use the strong property, but weak must be used in Xib, because the control is strong decorated when dragged into xib)@property (nonatomic,weak) UIButton *button;Basic data types such as 3.assign:cgfloat,nsinteger, enumerations, structs (non-OC objects)@property (nonatomic,assign) CGFloat 4.copy:• @property the selection of memory management policies1. Non-arc1> copy: only for Nsstring\block2> retain: OC object except

Often see the plug-in inside the function call only write a function name, do not write function parameters, and even parentheses do not write, for example, said:1 DOCTYPE HTML>2 HTML>3 Head>4 MetaCharSet= "Utf-8" />5 title>title>6 Scripttype= "Text/javascript">7 functionA1 () {8 Alert ('a');9 return '1';Ten }; One A - window.onload=function(){ - the //no parentheses represent all p

* from a LEFT join B on aid= bid and aid>3, return　　　　If a select * from a LEFT join B on aid= bid where aid>3　　　　Because a temporary table is generated when executing such a statement, the condition in the on in this temporary table is not necessarily true, because it is possible that the field value is null.When a temporary table is generated, it is filtered according to the Where condition, so the condition of where in the returned result must be true.　　　　　　　　　　Sql:left join, right join, INN

Question: The difference between | and the difference between and. 2. What types of data are involved in Java? What are the basic data types ?, Differences | And the difference between and. | Or is the logic or operation. | Short circuit or only logical judgment. If the left side is true, the judgment will not continue. Operator judgment is logical and F

Difference between vector and set, difference between vectorset Note: The content in this article is excerpted from the network and the accuracy needs to be verified. At this stage, it is only for your reference. Respect the work of the author, the original link: http://blog.csdn.net/wxdcxp/article/details/5279618 First,VectorIs a sequential container andSetIs an associated container.SetContains 0 or more

Difference between Servlet and JSP: difference between ServletJSP1. Basic Concepts 1.1 Servlet Servlet is a server-side Java application that has the characteristics of being independent from the platform and protocol and can generate dynamic Web pages. It serves as the intermediate layer between customer requests (Web browsers or other HTTP client programs) and server responses (databases or applications o

The difference between zepto and jquery: The difference between zepto and zepto uses 8 Summary, zeptojquery When talking about the cause of a strange event, we naturally think of the difference between the two. The first is the effect: In jquery, there are two effects: fadeIn and fadeOut, which are used to achieve the effect of fade-out. This is naturally a commo

, depending on the check.So, you come across this workaround: Replace the attr () method with the prop () method1 /**2 * UPDATEPRODUCT.HTMLS Update product Information3 */4$ (document). On ("click", ". table-bordered tbody tr a[class= ' up ']",function(){5Product = $.parsejson ($ ( This). Parents (' tr '). Find ("input"). EQ (1). Val ());6$( This). Parents (' tr '). Find ("input[type= ' checkbox ']"). Prop ("Checked",true);//after clicking on the Update button, tick the checkbox correspon

This function realizes the difference between two Unix timestamps, and returns two timestamps of days, hours, minutes, seconds, precision to seconds, and two parameters as timestamps, although the code is simple but useful. function Timediff ($begin _time, $end _time) { if ($begin _time Calculates the two time difference and returns the difference in days, min

The difference between print and echo in php and the difference between "" and ''can be output in the echo function at the same time, while in the print function, only one string can be output at the same time. At the same time, the echo function does not need parentheses, so the echo function is more like a statement than a function. Lt ;? Differences between print and echo in php and the

[Mysql] What is the difference between mysql and mariadb? What is the difference between mysqlmariadb? After leaving Sun, Mr. Widenius, the father of MySQL, thought that relying on Sun/Oracle to develop MySQL was very unreliable, so he decided to open another branch named MariaDB.MariaDB is compatible with MySQL in the vast majority of aspects. For developers, there is almost no

Get the difference of date in java, java get the difference of date Reprinted please indicate the source, thank you http://blog.csdn.net/harryweasley/article/details/42121485 When we want to calculate the difference value, we must think of "2014.12.14"-"2014.12.20" = 4. This method, but java does not directly give us this method, so what I want is to convert th

hyper-global variables commonly used in PHP$_get----->get Transfer Mode$_post----->post Transfer Mode$_request-----> can receive values for get and post two ways$GLOBALS-----> All the variables are in there.$_files-----> Upload files using$_server-----> System Environment variables$_session-----> Session control will be used.$_cookie-----> Session control will be used.differences in how get and post submissions are in a formGet is the URL where the parameter data queue is added to the Action pro

This article starting blog garden: http://jscode.cnblogs.com, reprint please indicate the source.The difference between element and node, Cilldren and childnodes Many friends do not know, this article tries to let you understand the differences between the concepts.node is a common name for any type of object in the DOM hierarchy, and node has many types, such as element nodes, attribute nodes, text nodes, annotation nodes, etc., which are distinguish

Webservice and MQ (MessageQueue) are common means of solving cross-platform communication, what are the differences between them?personally, the most essential difference is that webservice near real-time communication, while MQ is usually delayed communication. What do you mean? Because WebService is actually the local server program calls the method on the remote server, the interaction between the two, the request needs to wait for the requested se