重写 overwrite或者override: 相同的方法名称, 参数列表和返回类型
重载overload: 方法有相同的名字, 但是参数不同 (参数个数不同, 参数类型不同, 其中一个不同即可),
重写的方法的访问权限不能比父类的方法权限更严格.
比如父类的方法是protected, 那么子类覆写的方法的权限是protected或者public
overwrite:
class Person {
private String name;
private int age;
public void setName(String name){this.name=name;}
public void setAge(int age) {this.age=age;}
public String getName(){return name;}
public int getAge(){return age;}
public String getInfo() {
return "Name: "+ name + "\n" +"age: "+ age;
}
}
class Student extends Person {
private String school;
public String getSchool() {return school;}
public void setSchool(String school)
{this.school =school;}
public String getInfo() {
return "Name: "+ getName() + "\nage: "+ getAge()
+ "\nschool: "+ school;
}
}
public class TestOverWrite {
public static void main(String arg[]){
Student student = new Student();
Person person = new Person();
person.setName("none");
person.setAge(1000);
student.setName("John");
student.setAge(18);
student.setSchool("SCH");
System.out.println(person.getInfo());
System.out.println(student.getInfo());
}
}
overload:
public class Test {
void max(int a , int b) {
System.out.println( a > b ? a : b );
}
void max(short a , short b) {
System.out.println("short");
System.out.println( a > b ? a : b );
}
void max(float a, float b) {
System.out.println( a > b ? a : b );
}
public static void main(String[] args) {
Test t = new Test();
t.max(3, 4);
short a = 3;
short b = 4;
t.max(a, b);
}
}