Java Object-oriented notation (1)

1. Create a class person

To create a memory partition diagram of an object:

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Assigning values to attributes, acting as

Object. property = Assignment.

Class person{string name;int age;public void Tell () {System.out.println ("name:" + name+ "+" Age: "+age);}} public class MethodDemo01 {public static void main (string[] args) {person per = Null;per = new Person ();p er.name = "Thystar "; Assignment per.age = 22;per.tell ();}}

After assignment, add data to the heap memory space

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2. Object-Oriented Programming

Encapsulation of the class:

To avoid arbitrary changes to properties in the class, define the property as private, called with Getter and setter methods: Right--->source-->Generate Getters and Setters

Class Person{private string name;private int age;public string getName () {return name;} public void SetName (String name) {this.name = name;} public int getage () {return age;} public void Setage (int.) {this.age = age;} public void Tell () {System.out.println ("name:" + getName () + "" + "Age:" +getage ());}} public class MethodDemo01 {public static void main (string[] args) {person per = Null;per = new Person ();p er.setname ("Thysta R ");p Er.setage;p Er.tell ();}}

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Anonymous objects

Class student{public void Tell () {System.out.println ("Hello thystar!");}}  public class Demo01 {/** * @param args */public static void main (string[] args) {//TODO auto-generated method stubstudent   Stu = new Student (); Stu.tell ();//Anonymous Object New Student (). tell (); Can only be used once}}

Construction method

Class Student{public Student () {System.out.println ("Hello Thystar");}}  public class Demo01 {/** * @param args */public static void main (string[] args) {//TODO auto-generated method stubstudent Stu = new Student ();}}

The construction method name is the same as the class name, and the tangent has no return value, but the parameter can be passed.

Class student{string Name;int age;public Student (String name, int age) {System.out.println ("name:" + name+ "" + "Age:" +age) ;}}  public class Demo01 {/** * @param args */public static void main (string[] args) {//TODO auto-generated method stubstudent Stu = new Student ("Thystar", 22);}}

The construction method is automatically defined by the system and its methods can be overloaded.

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Reference delivery

Class Ref1{int temp = 10;}  public class Demo02 {/** * @param args */public static void main (string[] args) {//TODO auto-generated method stubRef1 R1 = new Ref1 (); r1.temp=20; System.out.println (r1.temp); tell (R1); System.out.println (r1.temp);} public static void-Tell (Ref1 r2) {r2.temp = 30;}}

Output Result:

10

20

30

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public class Demo3 {/** * @param args */public static void main (string[] args) {//TODO auto-generated method stubstring s TR1 = "Hello"; System.out.println (STR1); tell (STR1); System.out.println (STR1);} public static void-tell (String str) {str = "Thystar";}}

Output Result:

Hello

Hello

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this keyword

How to use

• Represents a property in a class and calls a method

• Represents a construction method in this class

• Represents the current object

Class person{private string name;private int age;public person (String n,  int a) {        this ();  //calls the constructor method in this class this.name =  n;//represents the attribute This.age = a;} Public person () {System.out.println ("xxxxxxxxxxxxxx");} Public string getname ()  {return name;} Public void setname (String name)  {this.name = name;} Public int getage ()  {return age;} Public void setage (Int age)  {this.age = age;} Public void tell () {System.out.println ("Name:" + this.getname () + " " + "Age:" +this.getage ());// Calling methods}}public class thisdemo01 {/** *  @param  args */public static  Void main (String[] args)  {// todo auto-generated method stubperson p  = new person ("Thystar",  22);p. Tell ();}}

Static keyword

1. Use the static Declaration property--"Static Declaration global property

2. Using the static declaration method--called directly through the class name

3. Note: When using the static method, you can access only the properties and methods of the static declaration, not the properties and methods of the static declaration.

Static properties and methods are called directly with the class name.

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Java Object-oriented notation (1)