JavaBean constructor method This static keyword

Features of JavaBean:
? Private member properties
? Public Member Method
? There are get/set methods for assigning/taking values to member variables
? Empty construction Method
JavaBean that meet these conditions are called standard.

Construction Method
[modifier] Constructor Method name (formal parameter list) {
//0 to multiple executable statements to form the execution body of the construction method
}
class student{
Public Student () {
System.out.println ("This is the method of constructing the students ' class of NULL parameters");
}
}
class person{
private int id;
Public Person () {}//Null parameter construction method
Public person (int a) {///overloaded constructor method, with an int type argument
id = A;//assign a value to an instance variable in a construction method
System.out.println ("This is a construction method with parameters");
}
Public person (int a, int b) {
System.out.println ("This is a construction method with two parameters");
}
}
Considerations When constructing method definitions:
1. The construction method must have the same name as the class
2. The constructor does not return a value or void, and once the return value or void is added, the method is a member method, not a constructor.
class demo{
//public Demo () {} If no construction method is defined, the system automatically adds a non-parametric construction method
Public Void Show () {
System.out.println ("Hello World");
}
}
class demo{
Public Demo (int id) {
System.out.println ("This is a construction method with parameters");
}
}
//Define an employee class, analyze several members yourself, and then give member variables, construction methods, GetXxx ()/setxxx () methods,
//And a method for displaying all member information. and tested.
class employee{
private String name;
private String employeeId;
private int age;
//Construction method
Public Employee () {}
//getxxx ()/setxxx () method
Public String Getemployeeid () {
return Empoloyeeid;
}
Public void Setemployeeid (String employeeId) {
This.employeeid=empoloyeeid;
}
Public String GetName () {
return getName;
}
Public void SetName (String name) {
this.setname= name;
}
public int Getage () {
return age;
}
Public void Setage (int.) {
this.age = age;
}
Public Void Show () {
System.out.println ("Employee code is:" +getemployeeid + "name is:" +getname+ "Age is:" +getage ");
}
}
class employeetest{
Public static void Main (string[] args) {
//Create Objects
Employee E = new Employee ();
//Assign a value to a member variable
E.steemployeeid ("1234");
e.stename ("John Doe");
E.setage (+);
e.show ();
}
}
//define an arithmetic class MyMath, provide basic subtraction functionality, and then test.
Import java.util.scanner{
class mymath{
public int Add (int a, int b) {
return a+b;
}
Public int sub (int a, int b) {
return a-B;
}
public int num (int a, int b) {
return a*b;
}
public int div (int a, int b) {
return a/b;
}
}
//Test class
class mymathtest{
Scanner s = new Scanner (system.in);
System.out.println ("Enter the first number");
int a = S.nestint ();
System.out.println ("Enter a second number");
int b = S.testint ();
mymath mm = new MyMath ();
System.out.println (Mm.add (A, b));
System.out.println (Mm.sub (A, b));
System.out.println (Mm.mul (A, b));
System.out.println (Mm.div (A, b));
}
}

class person{
Public Person () {}
Public void Sayhai () {
System.out.println ("Hello");
}
Public void Speak (String content) {
//person P = new person ();
//P.sayhi ();
This.syahi ();//sayhi ();//Another method that calls this object can omit the This keyword
System.out.println ("I Want to say:" +content);
}
}

Class persontext{
public static void Main (string[] args) {
Person pp = new person ();
Pp.speak ();
}
}

//this keyword in the constructor method, initializes the member variable
class person{
private String name;
private int id;
private String gender;
Public Person () {}//NULL parameter construction method
//constructor with three parameters, because the parameter and member variable have the same name, the This keyword distinguishes
Public person (String name, int id,string gender) {
This.name=name;
this.id = ID;
this.gender = gander;
}
Public person (String name,int id) {
this.name = name;
this.id = ID;
}
}
The //this keyword is used to refer to the current object, and the This keyword can be used in construction methods
//*********************************************
member variable/member method with static modifier, called class variable/class method,
member variable/member method without static modifier is called instance variable/instance method

>>>>>>>>>>> static only access to static
class teacher{
public int num=10;
public static int num2 =;
Public Void Show () {
System.out.println (num);//implicitly tells you to access a member variable
System.out.println (This.num)//explicitly tells you that access is a member variable
}
}

static methods can be accessed by:
1. Static member Variables
2. Static member Methods
non-static methods can be accessed by:
1. Static/non-static member variables
2. Static/non-static member methods
to summarize, simply remember:
Static only access static, non-static two can access

The object initialization process consists of two aspects:
Construction of code block execution + construction method execution

Constructing blocks of code: Extracting common statements from the construction method and executing them before the construction method executes
Static code block: executed once at class load to initialize class (member variable)

JavaBean constructor method This static keyword