概念

使用

案例

public class PersonText {public static void main(String[] args) {Person person = new Person();person.name = "dq";person.age = 11;person.eat("番茄炒蛋");}
}class Person {/*** 姓名*/String name;/*** 年齡*/Integer age;/*** 方法-吃飯*/void eat(String lunch) {System.out.println(age + "歲的" + name + "吃" + lunch);}
}

對象的內存解析1

案例1

public class PersonText {public static void main(String[] args) {Person person1 = new Person();person1.name = "dq";person1.age = 11;person1.eat("番茄炒蛋");Person person2 = new Person();person2.name = "dq2";person2.age = 112;person2.eat("番茄炒蛋2");Person person3=person1;person3.eat("3");}
}class Person {/*** 姓名*/String name;/*** 年齡*/Integer age;/*** 方法-吃飯*/void eat(String lunch) {System.out.println(age + "歲的" + name + "吃" + lunch);}
}

對象的內存解析2

案例

成員變量和局部變量

案例

詳細

方法概念

分類

說明

return后面不寫東西

方法注意點

案例1

package lesson.l10_oop;/*** Illustration** @author DengQing* @version 1.0* @datetime 2022/7/1 9:02* @function*/
public class PersonDemo {public static void main(String[] args) {PersonObject person1 = new PersonObject();person1.name="tt";person1.age=30;person1.sex=1;person1.study();person1.addAge(2);person1.showAge();PersonObject person2 = new PersonObject();person2.name="oo";person2.age=18;person2.sex=2;person2.study();person2.addAge(2);person2.showAge();}
}class PersonObject {String name;int age;/***1是男性* 2是女性*/int sex;public void study() {System.out.println("studying");}public void showAge() {System.out.println("age:" + age);}public int addAge(int i) {this.age += i;return this.age;}
}

案例2

package lesson.l10_oop;/*** Illustration** @author DengQing* @version 1.0* @datetime 2022/7/1 9:16* @function 計算圓的面積*/
public class CircleText {public static void main(String[] args) {Circle circle = new Circle();circle.r = 0.5;System.out.println("圓的面積為" + circle.countArea());}
}class Circle {double r;public double countArea() {return Math.pow(r, 2) * 3.14;}
}

案例3

package lesson.l10_oop;/*** Illustration** @author DengQing* @version 1.0* @datetime 2022/7/1 9:46* @function*/
public class Method {public static void main(String[] args) {Method m=new Method();System.out.println("矩形的面積為："+m.method(10,8));}public int method(int m,int n){
//        寬for (int i = 0; i < n; i++) {
//            長for (int j = 0; j < m; j++) {System.out.print("*\t");}System.out.println();}return m*n;}
}