solid principles java

I. Introduction of annotations (annotation)Java introduces the annotation mechanism of source code in JDK5.1. What is an annotation?Annotations Add metadata to the code, which is descriptive information about the organization, data fields, and relationships of the data.More generally, annotations add more visual descriptions to program elements that are not related to the business logic of the program and are intended for use by specific tools or fram

Principles that Java method invocation procedures follow 1 First Java class files, calls to all methods are recorded through symbolic constants. The relevant content can be obtained through the analysis of class file 2 Find the corresponding method in the corresponding class according to the static type of the variables and the static types of the parameters.

be executed sequentially.3. Code Snippet 4 Results:For code block synchronization, you essentially need to get the monitor of the object in parentheses after the Synchronized keyword, because the contents of the parentheses in this code are this, and method1 and METHOD2 are called by the same object. So you need to compete for locks on the same object before entering the synchronization block, so you can only execute the synchronization blocks sequentially.Iv. SummarySynchronized is the most co

, how do you directly access the non-static members of the static inner class?New Outer.Inner (). function ();In other external classes, how do you directly access static members of static internal classes?Uter. Inner.function ();Note: When a static member is defined in an inner class, the inner class must be static.When a static method in an external class accesses an inner class, the inner class must also be static.When describing things, there is something inside the thing, which is described

invocationtargetexception * @throws illegalargumentexception * @throws illegalaccessexception * @throws Instantiationexception * @throws SecurityException * @throws nosuchmethodexception * @throws classnotfoundexception * /public static void Main (string[] args) throws ClassNotFoundException, Nosuchmethodexception, SecurityException, Instantiationexception, Illegalaccessexception, IllegalArgumentException, invocationtargetexception {method1 (); Method2 (); Method3 ();} Call static method public

methodaccept-language:zh-cn,zh;q=0.8//supported languages on the browser sideBlank line This empty line must have to be used to distinguish the request header from the request bodyRequest Body ...Specific implementation code:1PackageWebprogramingdemo;23ImportJava.io.IOException;4ImportJava.io.InputStream;5ImportJava.io.PrintWriter;6ImportJava.net.ServerSocket;7ImportJava.net.Socket;89PublicClassMytomcat {1011/**12*@paramArgs13*@throwsIOException14*/15//All content sent by the browser is printed

load the data into the client for parsing.Below is the core part of the SONP client implementation , through the JS assembly // provide the URL address of the JSONP service (regardless of the type of address, the resulting return value is a piece of JavaScript code) var url = "Http://localhost:8080/hello?callback=flightHandler"; // Create a script tag, set its properties var script = document.createelement (' script '); Script.setattribute (' src ',

General Usage principles of Java IO: Principle 1: Data Sources (destinations: 1. File: (byte stream) fileinputstream, fileoutputstream; (Character) filereader, filewriter 2. byte []: bytearrayinputstream, bytearrayoutputstream (byte stream) 3. Char []: chararrayreader, chararraywriter (character stream) 4. String: (byte stream) stringbufferinputstream, stringbufferouputstream (Batch stream) stringreader, st

in an ordered table AA[J+1] =A[j]; atj--;//element Move back - if(j) - { - Break; - } - } inA[J+1] = temp;//Insert to correct position - } toPrintLine (A,i);//Print the results of each trip sort + } - } the //Print the sort results each time * Static voidPrintLine (int[] arr,inti) $ {Panax NotoginsengSystem.out.println (i+ ":"); - intArrlength=a

case that you can understand.5. To learn theory with practice (to achieve the most urgent needs around you, such as a recipe, a random daily order)6. Don't be fooled by the new technology.7. Everyone can not learn all the technology.8. Find your own features.9. Be good at walking alone in the dark.10. Give yourself a reason to fully convince yourself (for example, I want to leave my parents, I want to prove to my lover, I want to do what I like, I can do challenging work, I want to go to Beijin

(not to be continued)A. CookiesCookies are used to record a user's behavior over time, and it has two versions: version 0 and version 1, respectively, corresponding to the two response headers Set-cookie and Set-cookie2, but the Servlet specification does not support the Set-cookie2 response header, The actual properties of Set-cookie2 can be set in Set-cookie.The properties of Version 0 are as followsThe properties of Version 1 are as follows1 How cookies are used[

class, but interacting with the upper interface of a specific class.5. Interface Isolation principle (Interface segregation Principle)It is better to use multiple-specificity interfaces than to use a total interface, but not to transition;An interface cannot be too bloated;High cohesionWhen the functionality of a software system expands, the pressure of the changes will not affect other objects that go;UML instances:Model can become a model as long as it meets the condition of good stature, and

Java exception handling involves the program flow of the jump, so the virtual machine needs to save the program's execution process, so that the exception occurs when the correct jump, which also causes the use of exceptions will incur additional overhead, so be careful to use the exception.There are several principles for using exceptions:1, as far as possible to avoid the use of exceptions, the anomaly de

the Map interface have a predictable sequence of iterations. The difference between this implementation and HASHMAP is that Linkedhashmap maintains a two-way loop linked list. This list defines the order of the iterations, which is usually the order in which the elements will be held.It is important to note that if you re-deposit the key in the map, the position of the key will not change, just replace the value.Summarize:The difference between HashMap and Linkedhashmap is that HashMap is unord

intuitively without confusion.You should not declare a data field from another data domain.5. Use the class name to refer to static variables and methods.6. Do not initialize the static data field directly from the constructor by passing parameters. It is best to use static set methods to change the static data field.7, class modifier private(can only be accessed in this class),default (can only be accessed in the same package), protected(could be accessed by classes and subclasses in the same

category in the urban area distributed deployment capabilities, once encountering performance bottlenecks, and then want to implement distributed deployment is impossible, this method is not feasible.5, instanceof' A ' instanceof Character: compilation does not pass, because instance can only be used for object judgments and cannot be used for basic types of judgments.Null instanceof String: The return value is false, and if the left operand is null, the result returns false directly and no lon

Opening and closing principle OCP (Open for extension,closed for modification). The core idea of open and close principle is that an object is opened to expansion and closed to modification. In fact, the opening and closing principle means that changes to the class are made by adding code rather than altering the existing code. In other words, once the software developer writes out the code that can be run, it should not change it, but to ensure that it can continue to run, how to do this? Th

Niurou y = new Malaniurou (guodi);/to a spicy beef maodu x = new Maodu (y);//on the basis of spicy beef and then a big knife belly System.out.println ("A total point" + X.name () + ", Total consumption" +s.cost ()); } Output results: 11 A total of the Tai long 燚 hotpot flavor pot of the original pot + spicy beef + broadsword belly, a total consumption of 135 The above is a small set to introduce the Java decorator Model (from the re