Java中超详细this与super的概念和用法

class Student extends Person{

 public Student(String name, int age, String nation) {
  super(name);
 }
}

public class Person{
 private String name;
 private int age;
 private static String nation = "chinese";

 public Person(String name) {
  this.name = name;
 }

 public Person(String name, int age) {
  //初始化方法必须放到第一行
  this(name);
  this.age = age;
 }

 //局部变量name和age屏蔽了name和age属性,用this进行标识
 public Person(String name, int age,String nation) {
  this.name = name;
  this.age = age;
  //this可以调用到静态属性
  this.nation = nation;
 }


 public void test(){
  System.out.println("测试");
 }

 public static void test2(){
  //静态方法内不能出现this或super
  System.out.println("测试");
 }

 public void print(){
  //调用类内部的方法(toString已重写)加不加this都行
  this.toString();
 }

 @Override
 public String toString() {
  return "Person{" +
    "name='" + name + '\'' +
    ", age=" + age +
    '}';
 }

 public static void main(String[] args) {
  //这个this代表的student对象
  Student student = new Student("wzh",20,"chinese2");
  System.out.println(student.toString());
  //这个this代表的是person对象
  Person person = new Person("wzh2",20,"chinese3");
  System.out.println(student.toString());
  //扩展，全局变量nation的值最后是chinese3
  System.out.println(Person.nation);
 }
}

class Student extends Person{
 //这是默认的构造器内容，写出来是为了帮大家理解
 public Student(){
  super();
 }
}

public class Person{
 private String name;
 private int age;
}

class Student extends Person{

 public Student(String name, int age) {
  //任选一个父类有参构造
  //super(name, age);
  super(name);
 }
}

public class Person{
 private String name;
 private int age;

 public Person(String name, int age) {
  this.name = name;
  this.age = age;
 }

 public Person(String name) {
  this.name = name;
 }
}

class Student extends Person {
 private String name = "wzh2";

 @Override
 public String getName() {
  return "子类" + name;
 }

 public String getParentName(){
  //调用父类的方法
  return super.getName();
 }

 public static void main(String[] args) {
  Student student = new Student();
  System.out.println(student.getName());
  System.out.println(student.getParentName());
 }
}

public class Person{
 //protected意味着子类和同一包中可以访问
 protected String name = "wzh"; 
 protected int age = 20;

 public String getName() {
  return "父类" +name;
 }
}

class Student extends Person{

 public void parentDisplay(){
  System.out.println(super.age + super.name);
 }

 public static void main(String[] args) {
  new Student().parentDisplay(); //输出结果:20wzh
 }
}

public class Person{
 //protected意味着子类和同一包中可以访问
 protected String name = "wzh";
 protected int age = 20;
} 

public class Person{
 private String name;
 private int age;

 public void display(){
  //通过this或super调用到了Object的toString();
  System.out.println(super.toString());
 }

 public static void main(String[] args) {
  new Person().display(); //输出为Person@452b3a41
 }

}