<java-Object Oriented (b) >

 Packagethis_demo01;/** * Student class Template: * keywords in java: * This: * Call properties: * this.  Property Name: * The authority variable is the same as the member variable name, and the This keyword is used to represent the member variable * if the local variable and member variable names are different, this can be omitted * Call Method: * this. method ();     * This * call constructor can be omitted in this class: * this ();  Call the parameterless construct * This ("Kid", 2);   Call a parameter construct * This statement must be in the constructor first sentence * Static can be decorated: * "1" Property--static variable /class variable--defined in class * "2" Method--static method/class method--defined in class * "3" code block-static code block                     * "4" inner class--Static inner class * * Static modifier properties, methods, etc. are loaded into memory when the class is loaded * How to use: * The class name. Property name/Method name () * Object name. Attribute name/Method name () * Note: * Static method can only use or invoke static decorated variable or call Stati The C method * Cannot use a property that is not static decorated (member genus* While the static method is generated when the class is loaded, there are no objects in the shared zone * loaded into memory in the static method, so you cannot use a non-static method to not only invoke non-static properties and methods but also You can call static methods and properties * because the resulting can be called first.  *      *@authorWeguikin **/ Public classStudent {//Writing Properties    Private intIdnum;//School Number    PrivateString name;//name    Private CharGender//Sex//private String City; //location     Public StaticString City;//Location--//non-parametric construction     PublicStudent () {}//with a reference structure     PublicStudent (intIdnum,string name,Chargender,string City) {         This("Zhenjiang", ' Male '); //This (); //Call no parameter         This. Idnum =Idnum;  This. Name =name;  This. Gender =gender;  This. City =City ; }     PublicStudent (String name,Chargender) {         This. Name =name;  This. Gender =gender; }            //the public value assignment//School Number     Public intGetidnum () {returnIdnum; }     Public voidSetidnum (intidnum) {         This. Idnum =Idnum; }    //name     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }    //Sex     Public CharGetgender () {returngender; }     Public voidSetgender (Chargender) {         This. Gender =gender; }    //City     PublicString getcity () {returnCity ; }     Public voidsetcity (String city) { This. City =City ; }        //Method     Public voidInit () {System.out.println ("I am study number for:" +getidnum () + "" +getname () + ", Gender:" +getgender () + ", From:" +getcity ()); }}

 Packagethis_demo01;/*** Test class *@authorWeguikin **/ Public classTest { Public Static voidMain (string[] args) {//Creating ObjectsStudent su =NewStudent (123421, "West gram", ' Male ', "Africa"); Su.        Init ();   System.out.println (SU); //output is: memory addresssu.city= "Shanghai";//The object name. Propertiesstudent.city = "Beijing";//class name. PropertiesSystem.out.println (student.city);//             }}

04. Code BLOCK:

Package the_code_block_demo01;/** code BLOCK: * Concept: Use {} A section of code * classification: * Common code block code defined directly in a method or statement Block * Constructs code block directly written in class code block * Static code block using static declaration of code block * Same as Step code block multi-threaded object when speaking * * Execution Flow: * Static code blocks--load once * construct code blocks--Each creation of an object executes a Times * Construction method once per creation of an object * @author Weguikin **/ Public classDemoblock {Static intCity ;  PublicDemoblock () {System. out. println ("========== I am the construction method ========="); }    //"2" Construction code block{System. out. println ("============ I'm building a code block ============="); }        //"3" Static code block    Static{ City= A; System. out. println ("============ I am a static code block ==============="); }     Public Static voidMain (string[] args) {//Creating ObjectsDemoblock sum =NewDemoblock (); //"1" Ordinary code block        {            //code defined in a method            intAge = -; System. out. println (age); }         for(inti =1; I <Ten; i++) {            {                intAge = -; System. out. println (age); }        }    }}

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