public class Person {
public String name;
public int age;
public void eat(String dx) {
System.out.println("我在吃" + dx);
}
}
2-3、类的实例化
类的实例化
类名 对象名 = new 类名();
访问类的属性:对象名.属性名;
访问类的方法:对象名.方法名(形参列表);
public class Test {
public static void main(String[] args) {
// 类的实例化 对象
Person person = new Person();
// 访问对象的属性
String name = person.name;
int age = person.age;
System.out.println(name);// null
System.out.println(age);// 0
// 给对象的属性赋值
person.name = "jack";
person.age = 12;
System.out.println(person.name); // jack
System.out.println(person.age); // 12
// 调用对象的方法
person.eat("苹果");// 我在吃苹果
}
}
public class Person {
public String name;
public int age;
public Person(){
System.out.println("默认无参构造方法");
}
public Person(int age){
System.out.println("有参构造方法: "+age);
this.age = age;
}
public Person(String a, int age){
System.out.println("有参构造方法: "+age+","+a);
this.name = a;
this.age = age;
}
public void eat(String dx) {
System.out.println("我在吃" + dx);
}
}
public class Main {
public static void main(String[] aaa) {
Person p2 = new Person(12);
System.out.println(p2.age);
Person p3 = new Person("tom",12);
System.out.println(p3.name+", "+p3.age);
}
}
public class Person {
public String name;
public int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public Person(String name) {
this.name = name;
}
public Person(int age) {
this.age = age;
}
public Person() {
}
public void move(){
String name = "Jack";
// 此处使用的name是局部变量 Jack
System.out.println(name+"开始走路");
// this使用的name是成员变量
System.out.println(this.name+"开始走路");
}
}
public class Person {
public String name;
public int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
System.out.println("Person(String name, int age)");
}
public Person() {
// System.out.println("aaa");
this("tom",12);
System.out.println("Person()");
}
public void eat(){
System.out.println("eat");
this.sleep();
sleep();
System.out.println(this.name);
System.out.println(name);
}
public void sleep(){
System.out.println("sleep");
}
}
public class Person {
public String name;
public int age;
public void move(){
}
public void move(String name, int age){
}
public void move(int age, String name){
}
}